Add backlight idle script

.gitignore

@@ -13,4 +13,3 @@ home-assistant.log*
 zigbee.db*
 *__pycache__*
 .ha_run.lock
-

esphome/archive/owon-b35t-m5stack-core1.yaml

@@ -0,0 +1,293 @@
+substitutions:
+  name: "owon-b35t"
+  friendly_name: "OWON B35T Multimeter"
+  device_description: "M5Stack Core 1 BLE client for OWON B35T/B35T+ multimeter with local graphical display"
+  owon_mac_address: !secret owon_b35t_mac_address
+
+esphome:
+  name: ${name}
+  friendly_name: ${friendly_name}
+  comment: ${device_description}
+  min_version: 2024.6.0
+  includes:
+    - owon_b35t-m5stack-core1.h
+  project:
+    name: "custom.owon-b35t-m5stack"
+    version: "1.0"
+
+esp32:
+  board: m5stack-core-esp32
+  framework:
+    type: esp-idf
+    advanced:
+      minimum_chip_revision: "3.1"
+
+logger:
+  level: INFO
+
+api:
+  encryption:
+    key: !secret apikey
+
+ota:
+  platform: esphome
+  password: !secret ota
+
+wifi:
+  ssid: "Voltage-legacy"
+  password: !secret voltage_legacy_psk
+  #use_address: ${name}.home
+  power_save_mode: none
+  fast_connect: on
+  min_auth_mode: WPA2
+  ap:
+    ssid: "OWON B35T Fallback Hotspot"
+    password: !secret fallback_psk
+
+# Disabled to save RAM on the M5Stack Core 1. Re-enable temporarily if Wi-Fi recovery is needed.
+# captive_portal:
+
+interval:
+  - interval: 10s
+    then:
+      - lambda: |-
+          ESP_LOGI("mem", "heap free=%u min_free=%u internal_free=%u internal_largest=%u dma_free=%u dma_largest=%u",
+                   static_cast<unsigned>(esp_get_free_heap_size()),
+                   static_cast<unsigned>(esp_get_minimum_free_heap_size()),
+                   static_cast<unsigned>(heap_caps_get_free_size(MALLOC_CAP_INTERNAL)),
+                   static_cast<unsigned>(heap_caps_get_largest_free_block(MALLOC_CAP_INTERNAL)),
+                   static_cast<unsigned>(heap_caps_get_free_size(MALLOC_CAP_DMA)),
+                   static_cast<unsigned>(heap_caps_get_largest_free_block(MALLOC_CAP_DMA)));
+
+esp32_ble_tracker:
+  scan_parameters:
+    active: true
+    continuous: true
+
+ble_client:
+  - mac_address: ${owon_mac_address}
+    id: owon_ble_client
+    on_connect:
+      then:
+        - lambda: |-
+            owon_meter.on_connect();
+    on_disconnect:
+      then:
+        - lambda: |-
+            owon_meter.on_disconnect();
+        - logger.log:
+            level: WARN
+            format: "OWON BLE meter disconnected; restarting M5Stack to reclaim heap"
+        - delay: 1s
+        - lambda: |-
+            esp_restart();
+
+spi:
+  clk_pin: GPIO18
+  mosi_pin: GPIO23
+  miso_pin: GPIO19
+
+output:
+  - platform: ledc
+    pin: GPIO32
+    id: lcd_backlight
+
+light:
+  - platform: monochromatic
+    output: lcd_backlight
+    name: "${friendly_name} Backlight"
+    id: backlight
+    restore_mode: ALWAYS_ON
+
+font:
+  - file: "fonts/Roboto-Regular.ttf"
+    id: meter_font
+    size: 15
+    glyphs:
+      [
+        " ",
+        "!",
+        "%",
+        "+",
+        "-",
+        ".",
+        "/",
+        "0",
+        "1",
+        "2",
+        "3",
+        "4",
+        "5",
+        "6",
+        "7",
+        "8",
+        "9",
+        "<",
+        ">",
+        "A",
+        "B",
+        "C",
+        "D",
+        "E",
+        "F",
+        "G",
+        "H",
+        "I",
+        "L",
+        "M",
+        "N",
+        "O",
+        "P",
+        "R",
+        "S",
+        "T",
+        "U",
+        "V",
+        "W",
+        "X",
+        "Y",
+        "Z",
+        "a",
+        "c",
+        "d",
+        "e",
+        "f",
+        "g",
+        "h",
+        "i",
+        "k",
+        "m",
+        "n",
+        "o",
+        "r",
+        "s",
+        "t",
+        "u",
+        "v",
+        "w",
+        "y",
+        "z",
+        "°",
+        "µ",
+        "Ω",
+      ]
+
+display:
+  - platform: ili9xxx
+    id: lcd
+    model: M5STACK
+    cs_pin: GPIO14
+    dc_pin: GPIO27
+    reset_pin: GPIO33
+    invert_colors: true
+    color_palette: 8BIT
+    rotation: 0
+    update_interval: 500ms
+    lambda: |-
+      owon_meter.render(it, id(meter_font));
+
+binary_sensor:
+  - platform: gpio
+    id: button_a
+    pin:
+      number: GPIO39
+      inverted: true
+    internal: true
+    on_press:
+      then:
+        - lambda: |-
+            owon_meter.previous_button();
+  - platform: gpio
+    id: button_b
+    pin:
+      number: GPIO38
+      inverted: true
+    internal: true
+    on_click:
+      - min_length: 50ms
+        max_length: 1500ms
+        then:
+          - logger.log:
+              level: INFO
+              format: "OWON short press: %s"
+              args: ["owon_meter.selected_button_name()"]
+          - ble_client.ble_write:
+              id: owon_ble_client
+              service_uuid: "0000fff0-0000-1000-8000-00805f9b34fb"
+              characteristic_uuid: "0000fff3-0000-1000-8000-00805f9b34fb"
+              value: !lambda |-
+                std::vector<uint8_t> data = {owon_meter.selected_button, 0x01};
+                return data;
+      - min_length: 1500ms
+        max_length: 5000ms
+        then:
+          - logger.log:
+              level: INFO
+              format: "OWON long press: %s"
+              args: ["owon_meter.selected_button_name()"]
+          - ble_client.ble_write:
+              id: owon_ble_client
+              service_uuid: "0000fff0-0000-1000-8000-00805f9b34fb"
+              characteristic_uuid: "0000fff3-0000-1000-8000-00805f9b34fb"
+              value: !lambda |-
+                uint8_t press_type = (owon_meter.selected_button == 1 || owon_meter.selected_button == 5) ? 0x01 : 0x00;
+                std::vector<uint8_t> data = {owon_meter.selected_button, press_type};
+                return data;
+  - platform: gpio
+    id: button_c
+    pin:
+      number: GPIO37
+      inverted: true
+    internal: true
+    on_press:
+      then:
+        - lambda: |-
+            owon_meter.next_button();
+
+  - platform: template
+    name: "${friendly_name} Connected"
+    lambda: |-
+      return owon_meter.connected;
+  - platform: template
+    name: "${friendly_name} Overload"
+    lambda: |-
+      return owon_meter.overload;
+  - platform: template
+    name: "${friendly_name} Low Battery"
+    lambda: |-
+      return owon_meter.low_battery;
+
+sensor:
+  - platform: ble_client
+    type: characteristic
+    ble_client_id: owon_ble_client
+    id: owon_notify_source
+    internal: true
+    service_uuid: "0000fff0-0000-1000-8000-00805f9b34fb"
+    characteristic_uuid: "0000fff4-0000-1000-8000-00805f9b34fb"
+    notify: true
+    update_interval: never
+    lambda: |-
+      owon_meter.handle_notify(x);
+      return owon_meter.value();
+
+  - platform: wifi_signal
+    name: "${friendly_name} WiFi Signal"
+    update_interval: 60s
+
+text_sensor:
+  - platform: template
+    name: "${friendly_name} Reading"
+    update_interval: 2s
+    lambda: |-
+      return owon_meter.reading_text();
+  - platform: template
+    name: "${friendly_name} Unit"
+    update_interval: 2s
+    lambda: |-
+      return std::string(owon_meter.scale()) + owon_meter.unit();
+  - platform: template
+    name: "${friendly_name} Mode"
+    update_interval: 2s
+    lambda: |-
+      return owon_meter.mode_text();

esphome/archive/owon-b35t-m5stack-core2.h

@@ -0,0 +1,658 @@
+/*
+ * ESPHome helper for OWON B35T/B35T+ BLE meter on M5Stack Core 1.
+ * Parser is based on the standalone Arduino sketch by Reaper7
+ * (Beerware license, Revision 42) and Dean Cording's owonb35 notes.
+ */
+#pragma once
+
+#include <cmath>
+#include <cstdint>
+#include <cstring>
+#include <string>
+#include <vector>
+#include "esp_heap_caps.h"
+#include "esp_system.h"
+#include "esphome/core/helpers.h"
+#include "esphome/components/i2c/i2c.h"
+#include "esphome/core/log.h"
+#include "esphome/components/display/display.h"
+
+namespace owon_b35t {
+
+using esphome::Color;
+using esphome::display::Display;
+
+static const char *const TAG = "owon_b35t";
+static const char *const POWER_TAG = "core2_power";
+static constexpr uint8_t AXP192_ADDR = 0x34;
+static esphome::i2c::I2CDevice axp192;
+static bool axp192_ready = false;
+
+static bool axp_write(uint8_t reg, uint8_t value) {
+  if (!axp192_ready) return false;
+  bool ok = axp192.write_byte(reg, value);
+  if (!ok) ESP_LOGW(POWER_TAG, "AXP192 write reg 0x%02X failed", reg);
+  return ok;
+}
+
+static bool axp_read(uint8_t reg, uint8_t *value) {
+  if (!axp192_ready) return false;
+  bool ok = axp192.read_byte(reg, value);
+  if (!ok) ESP_LOGW(POWER_TAG, "AXP192 read reg 0x%02X failed", reg);
+  return ok;
+}
+
+static void axp_update(uint8_t reg, uint8_t clear_mask, uint8_t set_mask) {
+  uint8_t value = 0;
+  if (!axp_read(reg, &value)) return;
+  value = (value & ~clear_mask) | set_mask;
+  axp_write(reg, value);
+}
+
+static uint8_t axp_dc_voltage_data(uint16_t millivolts) {
+  if (millivolts < 700) millivolts = 700;
+  if (millivolts > 3500) millivolts = 3500;
+  return static_cast<uint8_t>((millivolts - 700) / 25) & 0x7F;
+}
+
+static uint8_t axp_ldo_voltage_data(uint16_t millivolts) {
+  if (millivolts < 1800) millivolts = 1800;
+  if (millivolts > 3300) millivolts = 3300;
+  return static_cast<uint8_t>((millivolts - 1800) / 100) & 0x0F;
+}
+
+static void core2_axp192_set_lcd_voltage(uint16_t millivolts) {
+  uint8_t value = 0;
+  axp_read(0x27, &value);
+  axp_write(0x27, (value & 0x80) | axp_dc_voltage_data(millivolts));  // DCDC3, LCD backlight
+}
+
+static void core2_axp192_set_backlight(float brightness) {
+  if (brightness <= 0.0f) {
+    axp_update(0x12, 0x02, 0x00);  // DCDC3 off
+    return;
+  }
+  if (brightness > 1.0f) brightness = 1.0f;
+  uint16_t millivolts = static_cast<uint16_t>(2400 + brightness * 900);
+  core2_axp192_set_lcd_voltage(millivolts);
+  axp_update(0x12, 0x00, 0x02);  // DCDC3 on
+}
+
+static void core2_axp192_init(esphome::i2c::I2CBus *bus) {
+  axp192.set_i2c_bus(bus);
+  axp192.set_i2c_address(AXP192_ADDR);
+  axp192_ready = true;
+  ESP_LOGI(POWER_TAG, "Initializing M5Stack Core2 AXP192 LCD power");
+  axp_update(0x30, 0xF9, 0x02);  // Disable VBUS current limit, preserve bit 2.
+  axp_update(0x92, 0x07, 0x00);  // GPIO1 open-drain output.
+  axp_update(0x93, 0x07, 0x00);  // GPIO2 open-drain output.
+  axp_write(0x35, 0xA2);         // RTC battery charging.
+
+  uint8_t value = 0;
+  axp_read(0x26, &value);
+  axp_write(0x26, (value & 0x80) | axp_dc_voltage_data(3350));  // DCDC1 ESP32 VDD.
+  core2_axp192_set_lcd_voltage(2800);
+
+  uint8_t ldo2 = axp_ldo_voltage_data(3300);
+  uint8_t ldo3 = axp_ldo_voltage_data(2000);
+  axp_write(0x28, (ldo2 << 4) | ldo3);  // LDO2 LCD logic/SD, LDO3 vibrator.
+  axp_update(0x12, 0x00, 0x07);         // Enable DCDC1, DCDC3, LDO2.
+  axp_write(0x82, 0xFF);                // ADCs on.
+  axp_update(0x95, 0x8D, 0x84);         // GPIO4 setup, as M5Core2 library does.
+  axp_write(0x36, 0x4C);                // Power key timing.
+
+  // LCD reset through AXP192 GPIO4.
+  axp_update(0x96, 0x02, 0x00);
+  delay(100);
+  axp_update(0x96, 0x00, 0x02);
+  delay(100);
+
+  core2_axp192_set_backlight(1.0f);
+}
+
+static const uint8_t ACCU_BMP[32] = {
+    0b00000000, 0b00000000,
+    0b00000000, 0b00000000,
+    0b00000000, 0b00000000,
+    0b11111111, 0b11111110,
+    0b10000000, 0b00000010,
+    0b10000000, 0b00000011,
+    0b10000000, 0b00000011,
+    0b10000000, 0b00000011,
+    0b10000000, 0b00000011,
+    0b10000000, 0b00000011,
+    0b10000000, 0b00000011,
+    0b10000000, 0b00000010,
+    0b11111111, 0b11111110,
+    0b00000000, 0b00000000,
+    0b00000000, 0b00000000,
+    0b00000000, 0b00000000,
+};
+
+static const uint8_t BLE_BMP[32] = {
+    0b00000001, 0b10000000,
+    0b00000001, 0b11000000,
+    0b00010001, 0b01100000,
+    0b00011001, 0b00110000,
+    0b00001101, 0b00011000,
+    0b00000111, 0b00110000,
+    0b00000011, 0b01100000,
+    0b00000001, 0b11000000,
+    0b00000001, 0b11000000,
+    0b00000011, 0b01100000,
+    0b00000111, 0b00110000,
+    0b00001101, 0b00011000,
+    0b00011001, 0b00110000,
+    0b00010001, 0b01100000,
+    0b00000001, 0b11000000,
+    0b00000001, 0b10000000,
+};
+
+static const uint8_t DIODE_BMP[32] = {
+    0b00001000, 0b00011000,
+    0b00001100, 0b00011000,
+    0b00001110, 0b00011000,
+    0b00001111, 0b00011000,
+    0b00001111, 0b10011000,
+    0b00001111, 0b11011000,
+    0b00001111, 0b11111000,
+    0b11111111, 0b11111111,
+    0b11111111, 0b11111111,
+    0b00001111, 0b11111000,
+    0b00001111, 0b11011000,
+    0b00001111, 0b10011000,
+    0b00001111, 0b00011000,
+    0b00001110, 0b00011000,
+    0b00001100, 0b00011000,
+    0b00001000, 0b00011000,
+};
+
+static const uint8_t BUZZ_BMP[32] = {
+    0b00000000, 0b11000000,
+    0b00000001, 0b11000000,
+    0b00000011, 0b11000001,
+    0b00000111, 0b11000001,
+    0b00001111, 0b11000101,
+    0b11111111, 0b11000101,
+    0b11111111, 0b11010101,
+    0b11111111, 0b11010101,
+    0b11111111, 0b11010101,
+    0b11111111, 0b11010101,
+    0b11111111, 0b11000101,
+    0b00001111, 0b11000101,
+    0b00000111, 0b11000001,
+    0b00000011, 0b11000001,
+    0b00000001, 0b11000000,
+    0b00000000, 0b11000000,
+};
+
+class Meter {
+ public:
+  static constexpr uint8_t REGPLUSMINUS = 0x00;
+  static constexpr uint8_t FLAGPLUS = 0b00101011;
+  static constexpr uint8_t FLAGMINUS = 0b00101101;
+  static constexpr uint8_t REGDIG1 = 0x01;
+  static constexpr uint8_t REGDIG2 = 0x02;
+  static constexpr uint8_t REGDIG3 = 0x03;
+  static constexpr uint8_t REGDIG4 = 0x04;
+  static constexpr uint8_t REGPOINT = 0x06;
+  static constexpr uint8_t FLAGPOINT0 = 0b00110000;
+  static constexpr uint8_t FLAGPOINT1 = 0b00110001;
+  static constexpr uint8_t FLAGPOINT2 = 0b00110010;
+  static constexpr uint8_t FLAGPOINT3 = 0b00110100;
+  static constexpr uint8_t REGMODE = 0x07;
+  static constexpr uint8_t FLAGMODEHOLD = 0b00000010;
+  static constexpr uint8_t FLAGMODEREL = 0b00000100;
+  static constexpr uint8_t FLAGMODEAC = 0b00001000;
+  static constexpr uint8_t FLAGMODEDC = 0b00010000;
+  static constexpr uint8_t FLAGMODEAUTO = 0b00100000;
+  static constexpr uint8_t REGMINMAX = 0x08;
+  static constexpr uint8_t FLAGMIN = 0b00010000;
+  static constexpr uint8_t FLAGMAX = 0b00100000;
+  static constexpr uint8_t REGSCALE = 0x09;
+  static constexpr uint8_t FLAGSCALEDUTY = 0b00000010;
+  static constexpr uint8_t FLAGSCALEDIODE = 0b00000100;
+  static constexpr uint8_t FLAGSCALEBUZZ = 0b00001000;
+  static constexpr uint8_t FLAGSCALEMEGA = 0b00010000;
+  static constexpr uint8_t FLAGSCALEKILO = 0b00100000;
+  static constexpr uint8_t FLAGSCALEMILLI = 0b01000000;
+  static constexpr uint8_t FLAGSCALEMICRO = 0b10000000;
+  static constexpr uint8_t REGUNIT = 0x0a;
+  static constexpr uint8_t FLAGUNITFAHR = 0b00000001;
+  static constexpr uint8_t FLAGUNITGRAD = 0b00000010;
+  static constexpr uint8_t FLAGUNITNF = 0b00000100;
+  static constexpr uint8_t FLAGUNITHZ = 0b00001000;
+  static constexpr uint8_t FLAGUNITHFE = 0b00010000;
+  static constexpr uint8_t FLAGUNITOHM = 0b00100000;
+  static constexpr uint8_t FLAGUNITAMP = 0b01000000;
+  static constexpr uint8_t FLAGUNITVOLT = 0b10000000;
+
+  bool connected{false};
+  bool write_available{false};
+  bool is_plus{false};
+  bool low_battery{false};
+  bool overload{false};
+  bool has_reading{false};
+  uint8_t selected_button{1};
+  uint32_t last_notify_ms{0};
+
+  bool handle_notify(const std::vector<uint8_t> &data) {
+    if (data.size() > sizeof(this->raw_))
+      return false;
+    if (data.size() == 6 && data[1] >= 0xF0) {
+      memset(this->raw_, 0, sizeof(this->raw_));
+      memcpy(this->raw_, data.data(), data.size());
+      this->is_plus = true;
+      this->parse_plus_();
+    } else if (data.size() == 14 && data[12] == 0x0D && data[13] == 0x0A) {
+      memset(this->value_, 0, sizeof(this->value_));
+      memcpy(this->value_, data.data(), data.size());
+      this->is_plus = false;
+    } else {
+      ESP_LOGW(TAG, "Ignoring unexpected OWON frame length=%u", static_cast<unsigned>(data.size()));
+      return false;
+    }
+
+    this->overload = memcmp(this->value_, OVERLOAD_FRAME, sizeof(OVERLOAD_FRAME)) == 0;
+    this->display_value = this->calc_display_value_();
+    this->base_value = this->calc_base_value_();
+    this->has_reading = true;
+    this->last_notify_ms = millis();
+    return true;
+  }
+
+  void on_connect() {
+    this->connected = true;
+    this->write_available = true;
+  }
+
+  void on_disconnect() {
+    this->connected = false;
+    this->write_available = false;
+  }
+
+  float value() const { return this->display_value; }
+  float value_base() const { return this->base_value; }
+  bool negative() const { return (this->value_[REGPLUSMINUS] & FLAGMINUS) == FLAGMINUS; }
+  bool auto_range() const { return (this->value_[REGMODE] & FLAGMODEAUTO) == FLAGMODEAUTO; }
+  bool hold() const { return (this->value_[REGMODE] & FLAGMODEHOLD) == FLAGMODEHOLD; }
+  bool relative() const { return (this->value_[REGMODE] & FLAGMODEREL) == FLAGMODEREL; }
+  bool ac() const { return (this->value_[REGMODE] & FLAGMODEAC) == FLAGMODEAC; }
+  bool dc() const { return (this->value_[REGMODE] & FLAGMODEDC) == FLAGMODEDC; }
+  bool min_mode() const { return (this->value_[REGMINMAX] & FLAGMIN) == FLAGMIN; }
+  bool max_mode() const { return (this->value_[REGMINMAX] & FLAGMAX) == FLAGMAX; }
+  bool diode() const { return (this->value_[REGSCALE] & FLAGSCALEDIODE) == FLAGSCALEDIODE; }
+  bool continuity() const { return (this->value_[REGSCALE] & FLAGSCALEBUZZ) == FLAGSCALEBUZZ; }
+
+  const char *unit() const {
+    switch (this->value_[REGUNIT]) {
+      case FLAGUNITFAHR: return "°F";
+      case FLAGUNITGRAD: return "°C";
+      case FLAGUNITNF: return "nF";
+      case FLAGUNITHZ: return "Hz";
+      case FLAGUNITHFE: return "hFE";
+      case FLAGUNITOHM: return "Ω";
+      case FLAGUNITAMP: return "A";
+      case FLAGUNITVOLT: return "V";
+      default: return "";
+    }
+  }
+
+  const char *scale() const {
+    if ((this->value_[REGSCALE] & FLAGSCALEDUTY) == FLAGSCALEDUTY) return "%";
+    if ((this->value_[REGSCALE] & FLAGSCALEMEGA) == FLAGSCALEMEGA) return "M";
+    if ((this->value_[REGSCALE] & FLAGSCALEKILO) == FLAGSCALEKILO) return "k";
+    if ((this->value_[REGSCALE] & FLAGSCALEMILLI) == FLAGSCALEMILLI) return "m";
+    if ((this->value_[REGSCALE] & FLAGSCALEMICRO) == FLAGSCALEMICRO) return "µ";
+    return "";
+  }
+
+  std::string mode_text() const {
+    std::string out;
+    if (this->dc()) out += "DC ";
+    if (this->ac()) out += "AC ";
+    if (this->auto_range()) out += "AUTO ";
+    if (this->hold()) out += "HOLD ";
+    if (this->relative()) out += "REL ";
+    if (this->min_mode()) out += "MIN ";
+    if (this->max_mode()) out += "MAX ";
+    if (this->diode()) out += "DIODE ";
+    if (this->continuity()) out += "CONT ";
+    if (!out.empty()) out.pop_back();
+    return out;
+  }
+
+  std::string reading_text() const {
+    if (!this->connected) return "Disconnected";
+    if (!this->has_reading) return "Waiting for data";
+    if (this->overload) return "OL " + std::string(this->scale()) + this->unit();
+    char buf[48];
+    snprintf(buf, sizeof(buf), "%s%.4g %s%s", this->negative() ? "-" : "", std::fabs(this->display_value), this->scale(), this->unit());
+    return std::string(buf);
+  }
+
+  enum Kind { KIND_OTHER, KIND_VOLTAGE, KIND_CURRENT, KIND_RESISTANCE, KIND_FREQUENCY, KIND_CAPACITANCE, KIND_TEMP_C, KIND_TEMP_F, KIND_DUTY };
+  Kind kind() const {
+    if ((this->value_[REGSCALE] & FLAGSCALEDUTY) == FLAGSCALEDUTY) return KIND_DUTY;
+    switch (this->value_[REGUNIT]) {
+      case FLAGUNITVOLT: return KIND_VOLTAGE;
+      case FLAGUNITAMP: return KIND_CURRENT;
+      case FLAGUNITOHM: return KIND_RESISTANCE;
+      case FLAGUNITHZ: return KIND_FREQUENCY;
+      case FLAGUNITNF: return KIND_CAPACITANCE;
+      case FLAGUNITGRAD: return KIND_TEMP_C;
+      case FLAGUNITFAHR: return KIND_TEMP_F;
+      default: return KIND_OTHER;
+    }
+  }
+
+  const char *selected_button_name() const {
+    static const char *const names[] = {"SELECT", "RANGE", "HLD/LIG", "REL/BT", "HZ/DUTY", "MAX/MIN"};
+    uint8_t index = this->selected_button;
+    if (index < 1) index = 1;
+    if (index > 6) index = 6;
+    return names[index - 1];
+  }
+
+  void previous_button() {
+    if (this->selected_button > 1) this->selected_button--;
+  }
+  void next_button() {
+    if (this->selected_button < 6) this->selected_button++;
+  }
+
+  void render(Display &it, esphome::display::BaseFont *font) {
+    const Color bg(0, 0, 0);
+    const Color fg(210, 210, 210);
+    // Chosen to map to a neutral dark gray in the RGB332 8-bit display palette.
+    const Color inactive(80, 80, 80);
+    const Color yellow(255, 220, 0);
+    const Color blue(0, 80, 255);
+    const Color cyan(0, 255, 255);
+    const Color magenta(255, 0, 255);
+    const Color red(255, 0, 0);
+    const Color green(0, 220, 0);
+    const Color orange(255, 165, 0);
+
+    it.fill(bg);
+    bool status_active = this->connected && this->has_reading;
+    this->draw_icon_(it, 12, 8, 16, 16, ACCU_BMP, status_active ? (this->low_battery ? red : green) : inactive);
+    this->draw_icon_(it, 46, 8, 16, 16, BLE_BMP, this->connected ? blue : inactive);
+    this->label_(it, font, 86, 8, "AUTO", status_active && this->auto_range() ? fg : inactive);
+    this->label_(it, font, 138, 8, "MAX", status_active && this->max_mode() ? red : inactive);
+    this->label_(it, font, 178, 8, "MIN", status_active && this->min_mode() ? green : inactive);
+    this->label_(it, font, 218, 8, "HOLD", status_active && this->hold() ? blue : inactive);
+    this->label_(it, font, 270, 8, "REL", status_active && this->relative() ? Color(128, 128, 0) : inactive);
+
+    this->label_(it, font, 8, 66, "DC", status_active && this->dc() ? cyan : inactive);
+    this->label_(it, font, 8, 102, "AC", status_active && this->ac() ? magenta : inactive);
+
+    if (!this->connected) {
+      this->draw_digits_(it, "----", false, inactive);
+      it.print(160, 148, font, inactive, esphome::display::TextAlign::CENTER, "scan/connect");
+    } else if (!this->has_reading) {
+      this->draw_digits_(it, "8888", false, inactive);
+      it.print(160, 148, font, inactive, esphome::display::TextAlign::CENTER, "waiting");
+    } else if (this->overload) {
+      this->draw_digits_(it, " OL ", false, fg);
+    } else {
+      char d[5];
+      d[0] = this->digit_char_(REGDIG1);
+      d[1] = this->digit_char_(REGDIG2);
+      d[2] = this->digit_char_(REGDIG3);
+      d[3] = this->digit_char_(REGDIG4);
+      d[4] = 0;
+      this->draw_digits_(it, d, this->negative(), fg);
+      this->draw_decimal_points_(it, fg);
+    }
+
+    if (status_active) {
+      std::string unit_line = std::string(this->scale()) + this->unit();
+      it.print(270, 140, font, yellow, esphome::display::TextAlign::CENTER, unit_line.c_str());
+    }
+
+    bool bargraph_active = status_active && !this->overload;
+    this->draw_bargraph_(it, bargraph_active ? this->digits_from_buffer_() : 0, bargraph_active);
+    this->draw_icon_(it, 300, 148, 16, 16, DIODE_BMP, status_active && this->diode() ? magenta : inactive);
+    this->draw_icon_(it, 300, 174, 16, 16, BUZZ_BMP, status_active && this->continuity() ? orange : inactive);
+
+    it.filled_rectangle(34, 212, 40, 24, this->write_available ? fg : inactive);
+    it.filled_rectangle(108, 212, 100, 24, this->write_available ? fg : inactive);
+    it.filled_rectangle(242, 212, 40, 24, this->write_available ? fg : inactive);
+    it.print(54, 216, font, bg, esphome::display::TextAlign::TOP_CENTER, "<");
+    it.print(158, 216, font, bg, esphome::display::TextAlign::TOP_CENTER, this->selected_button_name());
+    it.print(262, 216, font, bg, esphome::display::TextAlign::TOP_CENTER, ">");
+  }
+
+ private:
+  uint8_t raw_[14]{};
+  uint8_t value_[14]{};
+  float display_value{NAN};
+  float base_value{NAN};
+  static constexpr uint8_t OVERLOAD_FRAME[5] = {0x2B, 0x3F, 0x30, 0x3A, 0x3F};
+
+  uint16_t digits_from_buffer_() const {
+    uint16_t out = 0;
+    if (this->value_[REGDIG1] >= '0' && this->value_[REGDIG1] <= '9') out += (this->value_[REGDIG1] - '0') * 1000;
+    if (this->value_[REGDIG2] >= '0' && this->value_[REGDIG2] <= '9') out += (this->value_[REGDIG2] - '0') * 100;
+    if (this->value_[REGDIG3] >= '0' && this->value_[REGDIG3] <= '9') out += (this->value_[REGDIG3] - '0') * 10;
+    if (this->value_[REGDIG4] >= '0' && this->value_[REGDIG4] <= '9') out += (this->value_[REGDIG4] - '0');
+    return out;
+  }
+
+  float calc_display_value_() const {
+    if (this->overload) return NAN;
+
+    if (this->is_plus) {
+      uint16_t pair1 = static_cast<uint16_t>(this->raw_[0]) | (static_cast<uint16_t>(this->raw_[1]) << 8);
+      uint8_t decimal = pair1 & 0x07;
+      if (decimal >= 7) return NAN;
+
+      uint16_t pair3 = static_cast<uint16_t>(this->raw_[4]) | (static_cast<uint16_t>(this->raw_[5]) << 8);
+      bool negative = pair3 >= 0x7FFF;
+      uint16_t digits = negative ? (pair3 & 0x7FFF) : pair3;
+      float v = static_cast<float>(digits) / std::pow(10.0f, decimal);
+      return negative ? -v : v;
+    }
+
+    uint8_t decimal = 0;
+    switch (this->value_[REGPOINT] & 0x07) {
+      case 0b001: decimal = 1; break;
+      case 0b010: decimal = 2; break;
+      case 0b100: decimal = 3; break;
+      default: break;
+    }
+    float v = static_cast<float>(this->digits_from_buffer_()) / std::pow(10.0f, decimal);
+    return this->negative() ? -v : v;
+  }
+
+  float calc_base_value_() const {
+    if (std::isnan(this->display_value)) return NAN;
+    if (this->value_[REGUNIT] == FLAGUNITNF) return this->display_value * 1e-9f;
+    if ((this->value_[REGSCALE] & FLAGSCALEMEGA) == FLAGSCALEMEGA) return this->display_value * 1e6f;
+    if ((this->value_[REGSCALE] & FLAGSCALEKILO) == FLAGSCALEKILO) return this->display_value * 1e3f;
+    if ((this->value_[REGSCALE] & FLAGSCALEMILLI) == FLAGSCALEMILLI) return this->display_value * 1e-3f;
+    if ((this->value_[REGSCALE] & FLAGSCALEMICRO) == FLAGSCALEMICRO) return this->display_value * 1e-6f;
+    return this->display_value;
+  }
+
+  void parse_plus_() {
+    memset(this->value_, 0, sizeof(this->value_));
+    this->value_[5] = 0x20;
+    this->value_[12] = 0x0D;
+    this->value_[13] = 0x0A;
+
+    uint16_t pair1 = static_cast<uint16_t>(this->raw_[0]) | (static_cast<uint16_t>(this->raw_[1]) << 8);
+    uint8_t function = (pair1 >> 6) & 0x0F;
+    uint8_t scale = (pair1 >> 3) & 0x07;
+    uint8_t decimal = pair1 & 0x07;
+
+    switch (decimal) {
+      case 0: this->value_[REGPOINT] = FLAGPOINT0; break;
+      case 1: this->value_[REGPOINT] = FLAGPOINT3; break;
+      case 2: this->value_[REGPOINT] = FLAGPOINT2; break;
+      case 3: this->value_[REGPOINT] = FLAGPOINT1; break;
+      default: break;
+    }
+
+    switch (function) {
+      case 0: this->value_[REGUNIT] |= FLAGUNITVOLT; this->value_[REGMODE] |= FLAGMODEDC; break;
+      case 1: this->value_[REGUNIT] |= FLAGUNITVOLT; this->value_[REGMODE] |= FLAGMODEAC; break;
+      case 2: this->value_[REGUNIT] |= FLAGUNITAMP; this->value_[REGMODE] |= FLAGMODEDC; break;
+      case 3: this->value_[REGUNIT] |= FLAGUNITAMP; this->value_[REGMODE] |= FLAGMODEAC; break;
+      case 4: this->value_[REGUNIT] |= FLAGUNITOHM; break;
+      case 5: this->value_[REGUNIT] |= FLAGUNITNF; break;
+      case 6: this->value_[REGUNIT] |= FLAGUNITHZ; break;
+      case 7: this->value_[REGSCALE] |= FLAGSCALEDUTY; break;
+      case 8: this->value_[REGUNIT] |= FLAGUNITGRAD; break;
+      case 9: this->value_[REGUNIT] |= FLAGUNITFAHR; break;
+      case 10: this->value_[REGSCALE] |= FLAGSCALEDIODE; break;
+      case 11: this->value_[REGSCALE] |= FLAGSCALEBUZZ; break;
+      case 12: this->value_[REGUNIT] |= FLAGUNITHFE; break;
+      default: break;
+    }
+
+    switch (scale) {
+      case 2: this->value_[REGSCALE] |= FLAGSCALEMICRO; break;
+      case 3: this->value_[REGSCALE] |= FLAGSCALEMILLI; break;
+      case 5: this->value_[REGSCALE] |= FLAGSCALEKILO; break;
+      case 6: this->value_[REGSCALE] |= FLAGSCALEMEGA; break;
+      default: break;
+    }
+
+    uint16_t pair2 = static_cast<uint16_t>(this->raw_[2]) | (static_cast<uint16_t>(this->raw_[3]) << 8);
+    if (pair2 & (1 << 0)) this->value_[REGMODE] |= FLAGMODEHOLD;
+    if (pair2 & (1 << 1)) this->value_[REGMODE] |= FLAGMODEREL;
+    if (pair2 & (1 << 2)) this->value_[REGMODE] |= FLAGMODEAUTO;
+    this->low_battery = (pair2 & (1 << 3)) != 0;
+    if (pair2 & (1 << 4)) this->value_[REGMINMAX] |= FLAGMIN;
+    if (pair2 & (1 << 5)) this->value_[REGMINMAX] |= FLAGMAX;
+
+    uint16_t pair3 = static_cast<uint16_t>(this->raw_[4]) | (static_cast<uint16_t>(this->raw_[5]) << 8);
+    if (decimal < 7) {
+      uint16_t digits = pair3;
+      if (pair3 < 0x7FFF) {
+        this->value_[REGPLUSMINUS] = FLAGPLUS;
+      } else {
+        this->value_[REGPLUSMINUS] = FLAGMINUS;
+        digits = pair3 & 0x7FFF;
+      }
+      this->value_[REGDIG1] = '0' + ((digits / 1000) % 10);
+      this->value_[REGDIG2] = '0' + ((digits / 100) % 10);
+      this->value_[REGDIG3] = '0' + ((digits / 10) % 10);
+      this->value_[REGDIG4] = '0' + (digits % 10);
+    } else {
+      memcpy(this->value_, OVERLOAD_FRAME, sizeof(OVERLOAD_FRAME));
+    }
+  }
+
+  char digit_char_(uint8_t reg) const {
+    uint8_t c = this->value_[reg];
+    return (c >= '0' && c <= '9') ? static_cast<char>(c) : ' ';
+  }
+
+  void label_(Display &it, esphome::display::BaseFont *font, int x, int y, const char *text, Color color) {
+    it.print(x, y, font, color, esphome::display::TextAlign::TOP_LEFT, text);
+  }
+
+  void draw_digits_(Display &it, const char *text, bool negative, Color color) {
+    if (negative) this->draw_segment_(it, 8, 88, 26, 9, true, color);
+    constexpr int digit_x = 40;
+    constexpr int digit_y = 35;
+    constexpr int digit_w = 50;
+    constexpr int digit_h = 88;
+    constexpr int digit_distance = 64;
+    for (int i = 0; i < 4; i++) {
+      this->draw_seven_segment_(it, digit_x + i * digit_distance, digit_y, digit_w, digit_h, text[i], color);
+    }
+  }
+
+  void draw_decimal_points_(Display &it, Color color) {
+    uint8_t p = this->value_[REGPOINT];
+    if ((p & FLAGPOINT1) == FLAGPOINT1) it.filled_rectangle(95, 117, 8, 10, color);
+    if ((p & FLAGPOINT2) == FLAGPOINT2) it.filled_rectangle(159, 117, 8, 10, color);
+    if ((p & FLAGPOINT3) == FLAGPOINT3) it.filled_rectangle(223, 117, 8, 10, color);
+  }
+
+  void draw_segment_(Display &it, int x, int y, int w, int h, bool horizontal, Color color) {
+    if (horizontal) {
+      int cap = h / 2;
+      it.filled_rectangle(x + cap, y, w - 2 * cap, h +1, color);
+      it.filled_triangle(x, y + cap, x + cap, y, x + cap, y + h, color);
+      it.filled_triangle(x + w, y + cap, x + w - cap, y, x + w - cap, y + h, color);
+    } else {
+      int cap = w / 2;
+      it.filled_rectangle(x, y + cap, w +1, h - 2 * cap, color);
+      it.filled_triangle(x + cap, y, x, y + cap, x + w, y + cap, color);
+      it.filled_triangle(x + cap, y + h, x, y + h - cap, x + w, y + h - cap, color);
+    }
+  }
+
+  void draw_icon_(Display &it, int x, int y, int w, int h, const uint8_t *data, Color color) {
+    for (int row = 0; row < h; row++) {
+      for (int col = 0; col < w; col++) {
+        uint8_t byte = data[row * ((w + 7) / 8) + (col / 8)];
+        if ((byte & (0x80 >> (col % 8))) != 0) {
+          it.draw_pixel_at(x + col, y + row, color);
+        }
+      }
+    }
+  }
+
+  void draw_seven_segment_(Display &it, int x, int y, int w, int h, char ch, Color color) {
+    bool a=false,b=false,c=false,d=false,e=false,f=false,g=false;
+    switch (ch) {
+      case '0': a=b=c=d=e=f=true; break;
+      case '1': b=c=true; break;
+      case '2': a=b=d=e=g=true; break;
+      case '3': a=b=c=d=g=true; break;
+      case '4': b=c=f=g=true; break;
+      case '5': a=c=d=f=g=true; break;
+      case '6': a=c=d=e=f=g=true; break;
+      case '7': a=b=c=true; break;
+      case '8': a=b=c=d=e=f=g=true; break;
+      case '9': a=b=c=d=f=g=true; break;
+      case 'O': a=b=c=d=e=f=true; break;
+      case 'L': d=e=f=true; break;
+      case '-': g=true; break;
+      default: break;
+    }
+    int t = 10;
+    int half = h / 2;
+    int gap = 1;
+
+    int top_y = y;
+    int mid_y = y + half - t / 2;
+    int bot_y = y + h - t;
+
+    int upper_v_y = top_y + t + gap;
+    int upper_v_h = mid_y - gap - upper_v_y;
+    int lower_v_y = mid_y + t + gap;
+    int lower_v_h = bot_y - gap - lower_v_y;
+
+    if (a) this->draw_segment_(it, x + t / 2, top_y, w - t, t, true, color);
+    if (b && upper_v_h > 0) this->draw_segment_(it, x + w - t, upper_v_y, t, upper_v_h, false, color);
+    if (c && lower_v_h > 0) this->draw_segment_(it, x + w - t, lower_v_y, t, lower_v_h, false, color);
+    if (d) this->draw_segment_(it, x + t / 2, bot_y, w - t, t, true, color);
+    if (e && lower_v_h > 0) this->draw_segment_(it, x, lower_v_y, t, lower_v_h, false, color);
+    if (f && upper_v_h > 0) this->draw_segment_(it, x, upper_v_y, t, upper_v_h, false, color);
+    if (g) this->draw_segment_(it, x + t / 2, mid_y, w - t, t, true, color);
+  }
+
+  void draw_bargraph_(Display &it, uint16_t digits, bool active) {
+    const Color fg(255, 255, 255);
+    const Color inactive(80, 80, 80);
+    uint16_t mapped = active ? static_cast<uint16_t>(digits * 240 / 6000) : 0;
+    if (mapped > 240) mapped = 240;
+    for (uint16_t i = 0; i <= 240; i += 4) {
+      Color col = (active && i <= mapped) ? fg : inactive;
+      int h = (i % 40 == 0) ? 20 : ((i % 20 == 0) ? 15 : 10);
+      it.vertical_line(40 + i, 185 - h, h, col);
+    }
+    it.horizontal_line(35, 185, 250, inactive);
+  }
+};
+
+}  // namespace owon_b35t
+
+static owon_b35t::Meter owon_meter;

esphome/archive/owon-b35t-m5stack-core2.yaml

@@ -0,0 +1,316 @@
+# Derived work based on https://github.com/reaper7/M5Stack_BLE_client_Owon_B35T by reaper7.
+# AI (ChatGPT) has been used to adopt the Arduino sketch to ESPHome.
+# Ported to M5Stack Core2 due to memory constraints.
+
+substitutions:
+  name: "owon-b35t-m5stack-core2"
+  friendly_name: "OWON B35T Multimeter Core2"
+  device_description: "M5Stack Core2 BLE client for OWON B35T/B35T+ multimeter with local graphical display"
+  owon_mac_address: !secret owon_b35t_mac_address
+
+esphome:
+  name: ${name}
+  friendly_name: ${friendly_name}
+  comment: ${device_description}
+  min_version: 2024.6.0
+  includes:
+    - owon-b35t-m5stack-core2.h
+  on_boot:
+    priority: 850
+    then:
+      - lambda: |-
+          owon_b35t::core2_axp192_init(id(core2_i2c));
+  project:
+    name: "custom.owon-b35t-m5stack-core2"
+    version: "1.0"
+
+esp32:
+  board: m5stack-core2
+  flash_size: 16MB
+  framework:
+    type: esp-idf
+    advanced:
+      minimum_chip_revision: "3.1"
+      sram1_as_iram: true
+
+psram:
+  mode: quad
+  speed: 80MHz
+
+logger:
+  level: INFO
+
+api:
+  encryption:
+    key: !secret apikey
+
+ota:
+  platform: esphome
+  password: !secret ota
+
+wifi:
+  ssid: "Voltage-legacy"
+  password: !secret voltage_legacy_psk
+  #use_address: ${name}.home
+  power_save_mode: none
+  fast_connect: on
+  min_auth_mode: WPA2
+  ap:
+    ssid: "OWON B35T Fallback Hotspot"
+    password: !secret fallback_psk
+
+captive_portal:
+
+interval:
+  - interval: 10s
+    then:
+      - lambda: |-
+          ESP_LOGI("mem", "heap free=%u min_free=%u internal_free=%u internal_largest=%u dma_free=%u dma_largest=%u psram_free=%u psram_largest=%u",
+                   static_cast<unsigned>(esp_get_free_heap_size()),
+                   static_cast<unsigned>(esp_get_minimum_free_heap_size()),
+                   static_cast<unsigned>(heap_caps_get_free_size(MALLOC_CAP_INTERNAL)),
+                   static_cast<unsigned>(heap_caps_get_largest_free_block(MALLOC_CAP_INTERNAL)),
+                   static_cast<unsigned>(heap_caps_get_free_size(MALLOC_CAP_DMA)),
+                   static_cast<unsigned>(heap_caps_get_largest_free_block(MALLOC_CAP_DMA)),
+                   static_cast<unsigned>(heap_caps_get_free_size(MALLOC_CAP_SPIRAM)),
+                   static_cast<unsigned>(heap_caps_get_largest_free_block(MALLOC_CAP_SPIRAM)));
+
+esp32_ble_tracker:
+  scan_parameters:
+    active: true
+    continuous: true
+
+ble_client:
+  - mac_address: ${owon_mac_address}
+    id: owon_ble_client
+    on_connect:
+      then:
+        - lambda: |-
+            owon_meter.on_connect();
+    on_disconnect:
+      then:
+        - lambda: |-
+            owon_meter.on_disconnect();
+
+spi:
+  clk_pin: GPIO18
+  mosi_pin: GPIO23
+
+i2c:
+  id: core2_i2c
+  sda: GPIO21
+  scl: GPIO22
+  scan: true
+
+output:
+  - platform: template
+    type: float
+    id: lcd_backlight
+    write_action:
+      - lambda: |-
+          owon_b35t::core2_axp192_set_backlight(state);
+
+light:
+  - platform: monochromatic
+    output: lcd_backlight
+    name: "${friendly_name} Backlight"
+    id: backlight
+    restore_mode: ALWAYS_ON
+
+font:
+  - file: "fonts/Roboto-Regular.ttf"
+    id: meter_font
+    size: 15
+    glyphs:
+      [
+        " ",
+        "!",
+        "%",
+        "+",
+        "-",
+        ".",
+        "/",
+        "0",
+        "1",
+        "2",
+        "3",
+        "4",
+        "5",
+        "6",
+        "7",
+        "8",
+        "9",
+        "<",
+        ">",
+        "A",
+        "B",
+        "C",
+        "D",
+        "E",
+        "F",
+        "G",
+        "H",
+        "I",
+        "L",
+        "M",
+        "N",
+        "O",
+        "P",
+        "R",
+        "S",
+        "T",
+        "U",
+        "V",
+        "W",
+        "X",
+        "Y",
+        "Z",
+        "a",
+        "c",
+        "d",
+        "e",
+        "f",
+        "g",
+        "h",
+        "i",
+        "k",
+        "m",
+        "n",
+        "o",
+        "r",
+        "s",
+        "t",
+        "u",
+        "v",
+        "w",
+        "y",
+        "z",
+        "°",
+        "µ",
+        "Ω",
+      ]
+
+display:
+  - platform: mipi_spi
+    id: lcd
+    model: M5CORE2
+    update_interval: 500ms
+    lambda: |-
+      owon_meter.render(it, id(meter_font));
+
+touchscreen:
+  - platform: ft63x6
+    id: touch
+    display: lcd
+
+binary_sensor:
+  - platform: touchscreen
+    id: button_a
+    touchscreen_id: touch
+    x_min: 34
+    x_max: 74
+    y_min: 212
+    y_max: 240
+    internal: true
+    on_press:
+      then:
+        - lambda: |-
+            owon_meter.previous_button();
+  - platform: touchscreen
+    id: button_b
+    touchscreen_id: touch
+    x_min: 108
+    x_max: 208
+    y_min: 212
+    y_max: 240
+    internal: true
+    on_click:
+      - min_length: 50ms
+        max_length: 1500ms
+        then:
+          - logger.log:
+              level: INFO
+              format: "OWON short press: %s"
+              args: ["owon_meter.selected_button_name()"]
+          - ble_client.ble_write:
+              id: owon_ble_client
+              service_uuid: "0000fff0-0000-1000-8000-00805f9b34fb"
+              characteristic_uuid: "0000fff3-0000-1000-8000-00805f9b34fb"
+              value: !lambda |-
+                std::vector<uint8_t> data = {owon_meter.selected_button, 0x01};
+                return data;
+      - min_length: 1500ms
+        max_length: 5000ms
+        then:
+          - logger.log:
+              level: INFO
+              format: "OWON long press: %s"
+              args: ["owon_meter.selected_button_name()"]
+          - ble_client.ble_write:
+              id: owon_ble_client
+              service_uuid: "0000fff0-0000-1000-8000-00805f9b34fb"
+              characteristic_uuid: "0000fff3-0000-1000-8000-00805f9b34fb"
+              value: !lambda |-
+                uint8_t press_type = (owon_meter.selected_button == 1 || owon_meter.selected_button == 5) ? 0x01 : 0x00;
+                std::vector<uint8_t> data = {owon_meter.selected_button, press_type};
+                return data;
+  - platform: touchscreen
+    id: button_c
+    touchscreen_id: touch
+    x_min: 242
+    x_max: 282
+    y_min: 212
+    y_max: 240
+    internal: true
+    on_press:
+      then:
+        - lambda: |-
+            owon_meter.next_button();
+
+  - platform: template
+    name: "${friendly_name} Connected"
+    lambda: |-
+      return owon_meter.connected;
+  - platform: template
+    name: "${friendly_name} Overload"
+    lambda: |-
+      return owon_meter.overload;
+  - platform: template
+    name: "${friendly_name} Low Battery"
+    lambda: |-
+      return owon_meter.low_battery;
+
+sensor:
+  - platform: ble_client
+    type: characteristic
+    ble_client_id: owon_ble_client
+    id: owon_notify_source
+    internal: true
+    service_uuid: "0000fff0-0000-1000-8000-00805f9b34fb"
+    characteristic_uuid: "0000fff4-0000-1000-8000-00805f9b34fb"
+    notify: true
+    update_interval: never
+    lambda: |-
+      owon_meter.handle_notify(x);
+      return owon_meter.value();
+
+  - platform: wifi_signal
+    name: "${friendly_name} WiFi Signal"
+    update_interval: 60s
+
+text_sensor:
+  - platform: template
+    name: "${friendly_name} Reading"
+    update_interval: 1s
+    lambda: |-
+      return owon_meter.reading_text();
+  - platform: template
+    name: "${friendly_name} Unit"
+    update_interval: 1s
+    lambda: |-
+      return std::string(owon_meter.scale()) + owon_meter.unit();
+  - platform: template
+    name: "${friendly_name} Mode"
+    update_interval: 1s
+    lambda: |-
+      return owon_meter.mode_text();

esphome/archive/owon_b35t-m5stack-core1.h

@@ -0,0 +1,567 @@
+/*
+ * ESPHome helper for OWON B35T/B35T+ BLE meter on M5Stack Core 1.
+ * Parser is based on the standalone Arduino sketch by Reaper7
+ * (Beerware license, Revision 42) and Dean Cording's owonb35 notes.
+ */
+#pragma once
+
+#include <cmath>
+#include <cstdint>
+#include <cstring>
+#include <string>
+#include <vector>
+#include "esp_heap_caps.h"
+#include "esp_system.h"
+#include "esphome/core/helpers.h"
+#include "esphome/core/log.h"
+#include "esphome/components/display/display.h"
+
+namespace owon_b35t {
+
+using esphome::Color;
+using esphome::display::Display;
+
+static const char *const TAG = "owon_b35t";
+
+static const uint8_t ACCU_BMP[32] = {
+    0b00000000, 0b00000000,
+    0b00000000, 0b00000000,
+    0b00000000, 0b00000000,
+    0b11111111, 0b11111110,
+    0b10000000, 0b00000010,
+    0b10000000, 0b00000011,
+    0b10000000, 0b00000011,
+    0b10000000, 0b00000011,
+    0b10000000, 0b00000011,
+    0b10000000, 0b00000011,
+    0b10000000, 0b00000011,
+    0b10000000, 0b00000010,
+    0b11111111, 0b11111110,
+    0b00000000, 0b00000000,
+    0b00000000, 0b00000000,
+    0b00000000, 0b00000000,
+};
+
+static const uint8_t BLE_BMP[32] = {
+    0b00000001, 0b10000000,
+    0b00000001, 0b11000000,
+    0b00010001, 0b01100000,
+    0b00011001, 0b00110000,
+    0b00001101, 0b00011000,
+    0b00000111, 0b00110000,
+    0b00000011, 0b01100000,
+    0b00000001, 0b11000000,
+    0b00000001, 0b11000000,
+    0b00000011, 0b01100000,
+    0b00000111, 0b00110000,
+    0b00001101, 0b00011000,
+    0b00011001, 0b00110000,
+    0b00010001, 0b01100000,
+    0b00000001, 0b11000000,
+    0b00000001, 0b10000000,
+};
+
+static const uint8_t DIODE_BMP[32] = {
+    0b00001000, 0b00011000,
+    0b00001100, 0b00011000,
+    0b00001110, 0b00011000,
+    0b00001111, 0b00011000,
+    0b00001111, 0b10011000,
+    0b00001111, 0b11011000,
+    0b00001111, 0b11111000,
+    0b11111111, 0b11111111,
+    0b11111111, 0b11111111,
+    0b00001111, 0b11111000,
+    0b00001111, 0b11011000,
+    0b00001111, 0b10011000,
+    0b00001111, 0b00011000,
+    0b00001110, 0b00011000,
+    0b00001100, 0b00011000,
+    0b00001000, 0b00011000,
+};
+
+static const uint8_t BUZZ_BMP[32] = {
+    0b00000000, 0b11000000,
+    0b00000001, 0b11000000,
+    0b00000011, 0b11000001,
+    0b00000111, 0b11000001,
+    0b00001111, 0b11000101,
+    0b11111111, 0b11000101,
+    0b11111111, 0b11010101,
+    0b11111111, 0b11010101,
+    0b11111111, 0b11010101,
+    0b11111111, 0b11010101,
+    0b11111111, 0b11000101,
+    0b00001111, 0b11000101,
+    0b00000111, 0b11000001,
+    0b00000011, 0b11000001,
+    0b00000001, 0b11000000,
+    0b00000000, 0b11000000,
+};
+
+class Meter {
+ public:
+  static constexpr uint8_t REGPLUSMINUS = 0x00;
+  static constexpr uint8_t FLAGPLUS = 0b00101011;
+  static constexpr uint8_t FLAGMINUS = 0b00101101;
+  static constexpr uint8_t REGDIG1 = 0x01;
+  static constexpr uint8_t REGDIG2 = 0x02;
+  static constexpr uint8_t REGDIG3 = 0x03;
+  static constexpr uint8_t REGDIG4 = 0x04;
+  static constexpr uint8_t REGPOINT = 0x06;
+  static constexpr uint8_t FLAGPOINT0 = 0b00110000;
+  static constexpr uint8_t FLAGPOINT1 = 0b00110001;
+  static constexpr uint8_t FLAGPOINT2 = 0b00110010;
+  static constexpr uint8_t FLAGPOINT3 = 0b00110100;
+  static constexpr uint8_t REGMODE = 0x07;
+  static constexpr uint8_t FLAGMODEHOLD = 0b00000010;
+  static constexpr uint8_t FLAGMODEREL = 0b00000100;
+  static constexpr uint8_t FLAGMODEAC = 0b00001000;
+  static constexpr uint8_t FLAGMODEDC = 0b00010000;
+  static constexpr uint8_t FLAGMODEAUTO = 0b00100000;
+  static constexpr uint8_t REGMINMAX = 0x08;
+  static constexpr uint8_t FLAGMIN = 0b00010000;
+  static constexpr uint8_t FLAGMAX = 0b00100000;
+  static constexpr uint8_t REGSCALE = 0x09;
+  static constexpr uint8_t FLAGSCALEDUTY = 0b00000010;
+  static constexpr uint8_t FLAGSCALEDIODE = 0b00000100;
+  static constexpr uint8_t FLAGSCALEBUZZ = 0b00001000;
+  static constexpr uint8_t FLAGSCALEMEGA = 0b00010000;
+  static constexpr uint8_t FLAGSCALEKILO = 0b00100000;
+  static constexpr uint8_t FLAGSCALEMILLI = 0b01000000;
+  static constexpr uint8_t FLAGSCALEMICRO = 0b10000000;
+  static constexpr uint8_t REGUNIT = 0x0a;
+  static constexpr uint8_t FLAGUNITFAHR = 0b00000001;
+  static constexpr uint8_t FLAGUNITGRAD = 0b00000010;
+  static constexpr uint8_t FLAGUNITNF = 0b00000100;
+  static constexpr uint8_t FLAGUNITHZ = 0b00001000;
+  static constexpr uint8_t FLAGUNITHFE = 0b00010000;
+  static constexpr uint8_t FLAGUNITOHM = 0b00100000;
+  static constexpr uint8_t FLAGUNITAMP = 0b01000000;
+  static constexpr uint8_t FLAGUNITVOLT = 0b10000000;
+
+  bool connected{false};
+  bool write_available{false};
+  bool is_plus{false};
+  bool low_battery{false};
+  bool overload{false};
+  bool has_reading{false};
+  uint8_t selected_button{1};
+  uint32_t last_notify_ms{0};
+
+  bool handle_notify(const std::vector<uint8_t> &data) {
+    if (data.size() > sizeof(this->raw_))
+      return false;
+    if (data.size() == 6 && data[1] >= 0xF0) {
+      memset(this->raw_, 0, sizeof(this->raw_));
+      memcpy(this->raw_, data.data(), data.size());
+      this->is_plus = true;
+      this->parse_plus_();
+    } else if (data.size() == 14 && data[12] == 0x0D && data[13] == 0x0A) {
+      memset(this->value_, 0, sizeof(this->value_));
+      memcpy(this->value_, data.data(), data.size());
+      this->is_plus = false;
+    } else {
+      ESP_LOGW(TAG, "Ignoring unexpected OWON frame length=%u", static_cast<unsigned>(data.size()));
+      return false;
+    }
+
+    this->overload = memcmp(this->value_, OVERLOAD_FRAME, sizeof(OVERLOAD_FRAME)) == 0;
+    this->display_value = this->calc_display_value_();
+    this->base_value = this->calc_base_value_();
+    this->has_reading = true;
+    this->last_notify_ms = millis();
+    return true;
+  }
+
+  void on_connect() {
+    this->connected = true;
+    this->write_available = true;
+  }
+
+  void on_disconnect() {
+    this->connected = false;
+    this->write_available = false;
+  }
+
+  float value() const { return this->display_value; }
+  float value_base() const { return this->base_value; }
+  bool negative() const { return (this->value_[REGPLUSMINUS] & FLAGMINUS) == FLAGMINUS; }
+  bool auto_range() const { return (this->value_[REGMODE] & FLAGMODEAUTO) == FLAGMODEAUTO; }
+  bool hold() const { return (this->value_[REGMODE] & FLAGMODEHOLD) == FLAGMODEHOLD; }
+  bool relative() const { return (this->value_[REGMODE] & FLAGMODEREL) == FLAGMODEREL; }
+  bool ac() const { return (this->value_[REGMODE] & FLAGMODEAC) == FLAGMODEAC; }
+  bool dc() const { return (this->value_[REGMODE] & FLAGMODEDC) == FLAGMODEDC; }
+  bool min_mode() const { return (this->value_[REGMINMAX] & FLAGMIN) == FLAGMIN; }
+  bool max_mode() const { return (this->value_[REGMINMAX] & FLAGMAX) == FLAGMAX; }
+  bool diode() const { return (this->value_[REGSCALE] & FLAGSCALEDIODE) == FLAGSCALEDIODE; }
+  bool continuity() const { return (this->value_[REGSCALE] & FLAGSCALEBUZZ) == FLAGSCALEBUZZ; }
+
+  const char *unit() const {
+    switch (this->value_[REGUNIT]) {
+      case FLAGUNITFAHR: return "°F";
+      case FLAGUNITGRAD: return "°C";
+      case FLAGUNITNF: return "nF";
+      case FLAGUNITHZ: return "Hz";
+      case FLAGUNITHFE: return "hFE";
+      case FLAGUNITOHM: return "Ω";
+      case FLAGUNITAMP: return "A";
+      case FLAGUNITVOLT: return "V";
+      default: return "";
+    }
+  }
+
+  const char *scale() const {
+    if ((this->value_[REGSCALE] & FLAGSCALEDUTY) == FLAGSCALEDUTY) return "%";
+    if ((this->value_[REGSCALE] & FLAGSCALEMEGA) == FLAGSCALEMEGA) return "M";
+    if ((this->value_[REGSCALE] & FLAGSCALEKILO) == FLAGSCALEKILO) return "k";
+    if ((this->value_[REGSCALE] & FLAGSCALEMILLI) == FLAGSCALEMILLI) return "m";
+    if ((this->value_[REGSCALE] & FLAGSCALEMICRO) == FLAGSCALEMICRO) return "µ";
+    return "";
+  }
+
+  std::string mode_text() const {
+    std::string out;
+    if (this->dc()) out += "DC ";
+    if (this->ac()) out += "AC ";
+    if (this->auto_range()) out += "AUTO ";
+    if (this->hold()) out += "HOLD ";
+    if (this->relative()) out += "REL ";
+    if (this->min_mode()) out += "MIN ";
+    if (this->max_mode()) out += "MAX ";
+    if (this->diode()) out += "DIODE ";
+    if (this->continuity()) out += "CONT ";
+    if (!out.empty()) out.pop_back();
+    return out;
+  }
+
+  std::string reading_text() const {
+    if (!this->connected) return "Disconnected";
+    if (!this->has_reading) return "Waiting for data";
+    if (this->overload) return "OL " + std::string(this->scale()) + this->unit();
+    char buf[48];
+    snprintf(buf, sizeof(buf), "%s%.4g %s%s", this->negative() ? "-" : "", std::fabs(this->display_value), this->scale(), this->unit());
+    return std::string(buf);
+  }
+
+  enum Kind { KIND_OTHER, KIND_VOLTAGE, KIND_CURRENT, KIND_RESISTANCE, KIND_FREQUENCY, KIND_CAPACITANCE, KIND_TEMP_C, KIND_TEMP_F, KIND_DUTY };
+  Kind kind() const {
+    if ((this->value_[REGSCALE] & FLAGSCALEDUTY) == FLAGSCALEDUTY) return KIND_DUTY;
+    switch (this->value_[REGUNIT]) {
+      case FLAGUNITVOLT: return KIND_VOLTAGE;
+      case FLAGUNITAMP: return KIND_CURRENT;
+      case FLAGUNITOHM: return KIND_RESISTANCE;
+      case FLAGUNITHZ: return KIND_FREQUENCY;
+      case FLAGUNITNF: return KIND_CAPACITANCE;
+      case FLAGUNITGRAD: return KIND_TEMP_C;
+      case FLAGUNITFAHR: return KIND_TEMP_F;
+      default: return KIND_OTHER;
+    }
+  }
+
+  const char *selected_button_name() const {
+    static const char *const names[] = {"SELECT", "RANGE", "HLD/LIG", "REL/BT", "HZ/DUTY", "MAX/MIN"};
+    uint8_t index = this->selected_button;
+    if (index < 1) index = 1;
+    if (index > 6) index = 6;
+    return names[index - 1];
+  }
+
+  void previous_button() {
+    if (this->selected_button > 1) this->selected_button--;
+  }
+  void next_button() {
+    if (this->selected_button < 6) this->selected_button++;
+  }
+
+  void render(Display &it, esphome::display::BaseFont *font) {
+    const Color bg(0, 0, 0);
+    const Color fg(210, 210, 210);
+    // Chosen to map to a neutral dark gray in the RGB332 8-bit display palette.
+    const Color inactive(80, 80, 80);
+    const Color yellow(255, 220, 0);
+    const Color blue(0, 80, 255);
+    const Color cyan(0, 255, 255);
+    const Color magenta(255, 0, 255);
+    const Color red(255, 0, 0);
+    const Color green(0, 220, 0);
+    const Color orange(255, 165, 0);
+
+    it.fill(bg);
+    this->draw_icon_(it, 12, 8, 16, 16, ACCU_BMP, this->low_battery ? red : green);
+    this->draw_icon_(it, 46, 8, 16, 16, BLE_BMP, this->connected ? blue : inactive);
+    this->label_(it, font, 86, 8, "AUTO", this->auto_range() ? fg : inactive);
+    this->label_(it, font, 138, 8, "MAX", this->max_mode() ? red : inactive);
+    this->label_(it, font, 178, 8, "MIN", this->min_mode() ? green : inactive);
+    this->label_(it, font, 218, 8, "HOLD", this->hold() ? blue : inactive);
+    this->label_(it, font, 270, 8, "REL", this->relative() ? Color(128, 128, 0) : inactive);
+
+    this->label_(it, font, 8, 66, "DC", this->dc() ? cyan : inactive);
+    this->label_(it, font, 8, 102, "AC", this->ac() ? magenta : inactive);
+
+    if (!this->connected) {
+      this->draw_digits_(it, "----", false, inactive);
+      it.print(160, 148, font, inactive, esphome::display::TextAlign::CENTER, "scan/connect");
+    } else if (!this->has_reading) {
+      this->draw_digits_(it, "8888", false, inactive);
+      it.print(160, 148, font, inactive, esphome::display::TextAlign::CENTER, "waiting");
+    } else if (this->overload) {
+      this->draw_digits_(it, " OL ", false, fg);
+    } else {
+      char d[5];
+      d[0] = this->digit_char_(REGDIG1);
+      d[1] = this->digit_char_(REGDIG2);
+      d[2] = this->digit_char_(REGDIG3);
+      d[3] = this->digit_char_(REGDIG4);
+      d[4] = 0;
+      this->draw_digits_(it, d, this->negative(), fg);
+      this->draw_decimal_points_(it, fg);
+    }
+
+    std::string unit_line = std::string(this->scale()) + this->unit();
+    it.print(270, 140, font, yellow, esphome::display::TextAlign::CENTER, unit_line.c_str());
+
+    this->draw_bargraph_(it, this->has_reading && !this->overload ? this->digits_from_buffer_() : 0, this->has_reading && !this->overload);
+    this->draw_icon_(it, 300, 148, 16, 16, DIODE_BMP, this->diode() ? magenta : inactive);
+    this->draw_icon_(it, 300, 174, 16, 16, BUZZ_BMP, this->continuity() ? orange : inactive);
+
+    it.filled_rectangle(34, 212, 40, 24, this->write_available ? fg : inactive);
+    it.filled_rectangle(108, 212, 100, 24, this->write_available ? fg : inactive);
+    it.filled_rectangle(242, 212, 40, 24, this->write_available ? fg : inactive);
+    it.print(54, 216, font, bg, esphome::display::TextAlign::TOP_CENTER, "<");
+    it.print(158, 216, font, bg, esphome::display::TextAlign::TOP_CENTER, this->selected_button_name());
+    it.print(262, 216, font, bg, esphome::display::TextAlign::TOP_CENTER, ">");
+  }
+
+ private:
+  uint8_t raw_[14]{};
+  uint8_t value_[14]{};
+  float display_value{NAN};
+  float base_value{NAN};
+  static constexpr uint8_t OVERLOAD_FRAME[5] = {0x2B, 0x3F, 0x30, 0x3A, 0x3F};
+
+  uint16_t digits_from_buffer_() const {
+    uint16_t out = 0;
+    if (this->value_[REGDIG1] >= '0' && this->value_[REGDIG1] <= '9') out += (this->value_[REGDIG1] - '0') * 1000;
+    if (this->value_[REGDIG2] >= '0' && this->value_[REGDIG2] <= '9') out += (this->value_[REGDIG2] - '0') * 100;
+    if (this->value_[REGDIG3] >= '0' && this->value_[REGDIG3] <= '9') out += (this->value_[REGDIG3] - '0') * 10;
+    if (this->value_[REGDIG4] >= '0' && this->value_[REGDIG4] <= '9') out += (this->value_[REGDIG4] - '0');
+    return out;
+  }
+
+  float calc_display_value_() const {
+    if (this->overload) return NAN;
+
+    if (this->is_plus) {
+      uint16_t pair1 = static_cast<uint16_t>(this->raw_[0]) | (static_cast<uint16_t>(this->raw_[1]) << 8);
+      uint8_t decimal = pair1 & 0x07;
+      if (decimal >= 7) return NAN;
+
+      uint16_t pair3 = static_cast<uint16_t>(this->raw_[4]) | (static_cast<uint16_t>(this->raw_[5]) << 8);
+      bool negative = pair3 >= 0x7FFF;
+      uint16_t digits = negative ? (pair3 & 0x7FFF) : pair3;
+      float v = static_cast<float>(digits) / std::pow(10.0f, decimal);
+      return negative ? -v : v;
+    }
+
+    uint8_t decimal = 0;
+    switch (this->value_[REGPOINT] & 0x07) {
+      case 0b001: decimal = 1; break;
+      case 0b010: decimal = 2; break;
+      case 0b100: decimal = 3; break;
+      default: break;
+    }
+    float v = static_cast<float>(this->digits_from_buffer_()) / std::pow(10.0f, decimal);
+    return this->negative() ? -v : v;
+  }
+
+  float calc_base_value_() const {
+    if (std::isnan(this->display_value)) return NAN;
+    if (this->value_[REGUNIT] == FLAGUNITNF) return this->display_value * 1e-9f;
+    if ((this->value_[REGSCALE] & FLAGSCALEMEGA) == FLAGSCALEMEGA) return this->display_value * 1e6f;
+    if ((this->value_[REGSCALE] & FLAGSCALEKILO) == FLAGSCALEKILO) return this->display_value * 1e3f;
+    if ((this->value_[REGSCALE] & FLAGSCALEMILLI) == FLAGSCALEMILLI) return this->display_value * 1e-3f;
+    if ((this->value_[REGSCALE] & FLAGSCALEMICRO) == FLAGSCALEMICRO) return this->display_value * 1e-6f;
+    return this->display_value;
+  }
+
+  void parse_plus_() {
+    memset(this->value_, 0, sizeof(this->value_));
+    this->value_[5] = 0x20;
+    this->value_[12] = 0x0D;
+    this->value_[13] = 0x0A;
+
+    uint16_t pair1 = static_cast<uint16_t>(this->raw_[0]) | (static_cast<uint16_t>(this->raw_[1]) << 8);
+    uint8_t function = (pair1 >> 6) & 0x0F;
+    uint8_t scale = (pair1 >> 3) & 0x07;
+    uint8_t decimal = pair1 & 0x07;
+
+    switch (decimal) {
+      case 0: this->value_[REGPOINT] = FLAGPOINT0; break;
+      case 1: this->value_[REGPOINT] = FLAGPOINT3; break;
+      case 2: this->value_[REGPOINT] = FLAGPOINT2; break;
+      case 3: this->value_[REGPOINT] = FLAGPOINT1; break;
+      default: break;
+    }
+
+    switch (function) {
+      case 0: this->value_[REGUNIT] |= FLAGUNITVOLT; this->value_[REGMODE] |= FLAGMODEDC; break;
+      case 1: this->value_[REGUNIT] |= FLAGUNITVOLT; this->value_[REGMODE] |= FLAGMODEAC; break;
+      case 2: this->value_[REGUNIT] |= FLAGUNITAMP; this->value_[REGMODE] |= FLAGMODEDC; break;
+      case 3: this->value_[REGUNIT] |= FLAGUNITAMP; this->value_[REGMODE] |= FLAGMODEAC; break;
+      case 4: this->value_[REGUNIT] |= FLAGUNITOHM; break;
+      case 5: this->value_[REGUNIT] |= FLAGUNITNF; break;
+      case 6: this->value_[REGUNIT] |= FLAGUNITHZ; break;
+      case 7: this->value_[REGSCALE] |= FLAGSCALEDUTY; break;
+      case 8: this->value_[REGUNIT] |= FLAGUNITGRAD; break;
+      case 9: this->value_[REGUNIT] |= FLAGUNITFAHR; break;
+      case 10: this->value_[REGSCALE] |= FLAGSCALEDIODE; break;
+      case 11: this->value_[REGSCALE] |= FLAGSCALEBUZZ; break;
+      case 12: this->value_[REGUNIT] |= FLAGUNITHFE; break;
+      default: break;
+    }
+
+    switch (scale) {
+      case 2: this->value_[REGSCALE] |= FLAGSCALEMICRO; break;
+      case 3: this->value_[REGSCALE] |= FLAGSCALEMILLI; break;
+      case 5: this->value_[REGSCALE] |= FLAGSCALEKILO; break;
+      case 6: this->value_[REGSCALE] |= FLAGSCALEMEGA; break;
+      default: break;
+    }
+
+    uint16_t pair2 = static_cast<uint16_t>(this->raw_[2]) | (static_cast<uint16_t>(this->raw_[3]) << 8);
+    if (pair2 & (1 << 0)) this->value_[REGMODE] |= FLAGMODEHOLD;
+    if (pair2 & (1 << 1)) this->value_[REGMODE] |= FLAGMODEREL;
+    if (pair2 & (1 << 2)) this->value_[REGMODE] |= FLAGMODEAUTO;
+    this->low_battery = (pair2 & (1 << 3)) != 0;
+    if (pair2 & (1 << 4)) this->value_[REGMINMAX] |= FLAGMIN;
+    if (pair2 & (1 << 5)) this->value_[REGMINMAX] |= FLAGMAX;
+
+    uint16_t pair3 = static_cast<uint16_t>(this->raw_[4]) | (static_cast<uint16_t>(this->raw_[5]) << 8);
+    if (decimal < 7) {
+      uint16_t digits = pair3;
+      if (pair3 < 0x7FFF) {
+        this->value_[REGPLUSMINUS] = FLAGPLUS;
+      } else {
+        this->value_[REGPLUSMINUS] = FLAGMINUS;
+        digits = pair3 & 0x7FFF;
+      }
+      this->value_[REGDIG1] = '0' + ((digits / 1000) % 10);
+      this->value_[REGDIG2] = '0' + ((digits / 100) % 10);
+      this->value_[REGDIG3] = '0' + ((digits / 10) % 10);
+      this->value_[REGDIG4] = '0' + (digits % 10);
+    } else {
+      memcpy(this->value_, OVERLOAD_FRAME, sizeof(OVERLOAD_FRAME));
+    }
+  }
+
+  char digit_char_(uint8_t reg) const {
+    uint8_t c = this->value_[reg];
+    return (c >= '0' && c <= '9') ? static_cast<char>(c) : ' ';
+  }
+
+  void label_(Display &it, esphome::display::BaseFont *font, int x, int y, const char *text, Color color) {
+    it.print(x, y, font, color, esphome::display::TextAlign::TOP_LEFT, text);
+  }
+
+  void draw_digits_(Display &it, const char *text, bool negative, Color color) {
+    if (negative) this->draw_segment_(it, 8, 88, 26, 9, true, color);
+    constexpr int digit_x = 40;
+    constexpr int digit_y = 35;
+    constexpr int digit_w = 50;
+    constexpr int digit_h = 88;
+    constexpr int digit_distance = 64;
+    for (int i = 0; i < 4; i++) {
+      this->draw_seven_segment_(it, digit_x + i * digit_distance, digit_y, digit_w, digit_h, text[i], color);
+    }
+  }
+
+  void draw_decimal_points_(Display &it, Color color) {
+    uint8_t p = this->value_[REGPOINT];
+    if ((p & FLAGPOINT1) == FLAGPOINT1) it.filled_rectangle(95, 117, 8, 10, color);
+    if ((p & FLAGPOINT2) == FLAGPOINT2) it.filled_rectangle(159, 117, 8, 10, color);
+    if ((p & FLAGPOINT3) == FLAGPOINT3) it.filled_rectangle(223, 117, 8, 10, color);
+  }
+
+  void draw_segment_(Display &it, int x, int y, int w, int h, bool horizontal, Color color) {
+    if (horizontal) {
+      int cap = h / 2;
+      it.filled_rectangle(x + cap, y, w - 2 * cap, h, color);
+      it.filled_triangle(x, y + cap, x + cap, y, x + cap, y + h, color);
+      it.filled_triangle(x + w, y + cap, x + w - cap, y, x + w - cap, y + h, color);
+    } else {
+      int cap = w / 2;
+      it.filled_rectangle(x, y + cap, w, h - 2 * cap, color);
+      it.filled_triangle(x + cap, y, x, y + cap, x + w, y + cap, color);
+      it.filled_triangle(x + cap, y + h, x, y + h - cap, x + w, y + h - cap, color);
+    }
+  }
+
+  void draw_icon_(Display &it, int x, int y, int w, int h, const uint8_t *data, Color color) {
+    for (int row = 0; row < h; row++) {
+      for (int col = 0; col < w; col++) {
+        uint8_t byte = data[row * ((w + 7) / 8) + (col / 8)];
+        if ((byte & (0x80 >> (col % 8))) != 0) {
+          it.draw_pixel_at(x + col, y + row, color);
+        }
+      }
+    }
+  }
+
+  void draw_seven_segment_(Display &it, int x, int y, int w, int h, char ch, Color color) {
+    bool a=false,b=false,c=false,d=false,e=false,f=false,g=false;
+    switch (ch) {
+      case '0': a=b=c=d=e=f=true; break;
+      case '1': b=c=true; break;
+      case '2': a=b=d=e=g=true; break;
+      case '3': a=b=c=d=g=true; break;
+      case '4': b=c=f=g=true; break;
+      case '5': a=c=d=f=g=true; break;
+      case '6': a=c=d=e=f=g=true; break;
+      case '7': a=b=c=true; break;
+      case '8': a=b=c=d=e=f=g=true; break;
+      case '9': a=b=c=d=f=g=true; break;
+      case 'O': a=b=c=d=e=f=true; break;
+      case 'L': d=e=f=true; break;
+      case '-': g=true; break;
+      default: break;
+    }
+    int t = 10;
+    int half = h / 2;
+    int gap = 1;
+
+    int top_y = y;
+    int mid_y = y + half - t / 2;
+    int bot_y = y + h - t;
+
+    int upper_v_y = top_y + t + gap;
+    int upper_v_h = mid_y - gap - upper_v_y;
+    int lower_v_y = mid_y + t + gap;
+    int lower_v_h = bot_y - gap - lower_v_y;
+
+    if (a) this->draw_segment_(it, x + t / 2, top_y, w - t, t, true, color);
+    if (b && upper_v_h > 0) this->draw_segment_(it, x + w - t, upper_v_y, t, upper_v_h, false, color);
+    if (c && lower_v_h > 0) this->draw_segment_(it, x + w - t, lower_v_y, t, lower_v_h, false, color);
+    if (d) this->draw_segment_(it, x + t / 2, bot_y, w - t, t, true, color);
+    if (e && lower_v_h > 0) this->draw_segment_(it, x, lower_v_y, t, lower_v_h, false, color);
+    if (f && upper_v_h > 0) this->draw_segment_(it, x, upper_v_y, t, upper_v_h, false, color);
+    if (g) this->draw_segment_(it, x + t / 2, mid_y, w - t, t, true, color);
+  }
+
+  void draw_bargraph_(Display &it, uint16_t digits, bool active) {
+    const Color fg(255, 255, 255);
+    const Color inactive(80, 80, 80);
+    uint16_t mapped = active ? static_cast<uint16_t>(digits * 240 / 6000) : 0;
+    if (mapped > 240) mapped = 240;
+    for (uint16_t i = 0; i <= 240; i += 4) {
+      Color col = (active && i <= mapped) ? fg : inactive;
+      int h = (i % 40 == 0) ? 20 : ((i % 20 == 0) ? 15 : 10);
+      it.vertical_line(40 + i, 185 - h, h, col);
+    }
+    it.horizontal_line(35, 185, 250, inactive);
+  }
+};
+
+}  // namespace owon_b35t
+
+static owon_b35t::Meter owon_meter;

esphome/lab-ble-proxy.h

@@ -0,0 +1,741 @@
+/*
+ * ESPHome helper for OWON B35T/B35T+ BLE meter on M5Stack Core 2.
+ * Parser is based on the standalone Arduino sketch by Reaper7
+ * (Beerware license, Revision 42) and Dean Cording's owonb35 notes.
+ */
+#pragma once
+
+#include <cmath>
+#include <cstdint>
+#include <cstring>
+#include <string>
+#include <vector>
+#include "esp_heap_caps.h"
+#include "esp_system.h"
+#include "esphome/core/helpers.h"
+#include "esphome/components/i2c/i2c.h"
+#include "esphome/core/log.h"
+#include "esphome/components/display/display.h"
+
+namespace owon_b35t {
+
+using esphome::Color;
+using esphome::display::Display;
+
+static const char *const TAG = "owon_b35t";
+static const char *const POWER_TAG = "core2_power";
+static constexpr uint8_t AXP192_ADDR = 0x34;
+static esphome::i2c::I2CDevice axp192;
+static bool axp192_ready = false;
+
+static bool axp_write(uint8_t reg, uint8_t value) {
+  if (!axp192_ready) return false;
+  bool ok = axp192.write_byte(reg, value);
+  if (!ok) ESP_LOGW(POWER_TAG, "AXP192 write reg 0x%02X failed", reg);
+  return ok;
+}
+
+static bool axp_read(uint8_t reg, uint8_t *value) {
+  if (!axp192_ready) return false;
+  bool ok = axp192.read_byte(reg, value);
+  if (!ok) ESP_LOGW(POWER_TAG, "AXP192 read reg 0x%02X failed", reg);
+  return ok;
+}
+
+static void axp_update(uint8_t reg, uint8_t clear_mask, uint8_t set_mask) {
+  uint8_t value = 0;
+  if (!axp_read(reg, &value)) return;
+  value = (value & ~clear_mask) | set_mask;
+  axp_write(reg, value);
+}
+
+static uint8_t axp_dc_voltage_data(uint16_t millivolts) {
+  if (millivolts < 700) millivolts = 700;
+  if (millivolts > 3500) millivolts = 3500;
+  return static_cast<uint8_t>((millivolts - 700) / 25) & 0x7F;
+}
+
+static uint8_t axp_ldo_voltage_data(uint16_t millivolts) {
+  if (millivolts < 1800) millivolts = 1800;
+  if (millivolts > 3300) millivolts = 3300;
+  return static_cast<uint8_t>((millivolts - 1800) / 100) & 0x0F;
+}
+
+static void core2_axp192_set_lcd_voltage(uint16_t millivolts) {
+  uint8_t value = 0;
+  axp_read(0x27, &value);
+  axp_write(0x27, (value & 0x80) | axp_dc_voltage_data(millivolts));  // DCDC3, LCD backlight
+}
+
+static void core2_axp192_set_backlight(float brightness) {
+  if (brightness <= 0.0f) {
+    axp_update(0x12, 0x02, 0x00);  // DCDC3 off
+    return;
+  }
+  if (brightness > 1.0f) brightness = 1.0f;
+  uint16_t millivolts = static_cast<uint16_t>(2400 + brightness * 900);
+  core2_axp192_set_lcd_voltage(millivolts);
+  axp_update(0x12, 0x00, 0x02);  // DCDC3 on
+}
+
+static void core2_axp192_init(esphome::i2c::I2CBus *bus) {
+  axp192.set_i2c_bus(bus);
+  axp192.set_i2c_address(AXP192_ADDR);
+  axp192_ready = true;
+  ESP_LOGI(POWER_TAG, "Initializing M5Stack Core2 AXP192 LCD power");
+  axp_update(0x30, 0xF9, 0x02);  // Disable VBUS current limit, preserve bit 2.
+  axp_update(0x92, 0x07, 0x00);  // GPIO1 open-drain output.
+  axp_update(0x93, 0x07, 0x00);  // GPIO2 open-drain output.
+  axp_write(0x35, 0xA2);         // RTC battery charging.
+
+  uint8_t value = 0;
+  axp_read(0x26, &value);
+  axp_write(0x26, (value & 0x80) | axp_dc_voltage_data(3350));  // DCDC1 ESP32 VDD.
+  core2_axp192_set_lcd_voltage(2800);
+
+  uint8_t ldo2 = axp_ldo_voltage_data(3300);
+  uint8_t ldo3 = axp_ldo_voltage_data(2000);
+  axp_write(0x28, (ldo2 << 4) | ldo3);  // LDO2 LCD logic/SD, LDO3 vibrator.
+  axp_update(0x12, 0x00, 0x07);         // Enable DCDC1, DCDC3, LDO2.
+  axp_write(0x82, 0xFF);                // ADCs on.
+  axp_update(0x95, 0x8D, 0x84);         // GPIO4 setup, as M5Core2 library does.
+  axp_write(0x36, 0x4C);                // Power key timing.
+
+  // LCD reset through AXP192 GPIO4.
+  axp_update(0x96, 0x02, 0x00);
+  delay(100);
+  axp_update(0x96, 0x00, 0x02);
+  delay(100);
+
+  core2_axp192_set_backlight(1.0f);
+}
+
+static const uint8_t ACCU_BMP[32] = {
+    0b00000000, 0b00000000,
+    0b00000000, 0b00000000,
+    0b00000000, 0b00000000,
+    0b11111111, 0b11111110,
+    0b10000000, 0b00000010,
+    0b10000000, 0b00000011,
+    0b10000000, 0b00000011,
+    0b10000000, 0b00000011,
+    0b10000000, 0b00000011,
+    0b10000000, 0b00000011,
+    0b10000000, 0b00000011,
+    0b10000000, 0b00000010,
+    0b11111111, 0b11111110,
+    0b00000000, 0b00000000,
+    0b00000000, 0b00000000,
+    0b00000000, 0b00000000,
+};
+
+static const uint8_t BLE_BMP[32] = {
+    0b00000001, 0b10000000,
+    0b00000001, 0b11000000,
+    0b00010001, 0b01100000,
+    0b00011001, 0b00110000,
+    0b00001101, 0b00011000,
+    0b00000111, 0b00110000,
+    0b00000011, 0b01100000,
+    0b00000001, 0b11000000,
+    0b00000001, 0b11000000,
+    0b00000011, 0b01100000,
+    0b00000111, 0b00110000,
+    0b00001101, 0b00011000,
+    0b00011001, 0b00110000,
+    0b00010001, 0b01100000,
+    0b00000001, 0b11000000,
+    0b00000001, 0b10000000,
+};
+
+static const uint8_t DIODE_BMP[32] = {
+    0b00001000, 0b00011000,
+    0b00001100, 0b00011000,
+    0b00001110, 0b00011000,
+    0b00001111, 0b00011000,
+    0b00001111, 0b10011000,
+    0b00001111, 0b11011000,
+    0b00001111, 0b11111000,
+    0b11111111, 0b11111111,
+    0b11111111, 0b11111111,
+    0b00001111, 0b11111000,
+    0b00001111, 0b11011000,
+    0b00001111, 0b10011000,
+    0b00001111, 0b00011000,
+    0b00001110, 0b00011000,
+    0b00001100, 0b00011000,
+    0b00001000, 0b00011000,
+};
+
+static const uint8_t BUZZ_BMP[32] = {
+    0b00000000, 0b11000000,
+    0b00000001, 0b11000000,
+    0b00000011, 0b11000001,
+    0b00000111, 0b11000001,
+    0b00001111, 0b11000101,
+    0b11111111, 0b11000101,
+    0b11111111, 0b11010101,
+    0b11111111, 0b11010101,
+    0b11111111, 0b11010101,
+    0b11111111, 0b11010101,
+    0b11111111, 0b11000101,
+    0b00001111, 0b11000101,
+    0b00000111, 0b11000001,
+    0b00000011, 0b11000001,
+    0b00000001, 0b11000000,
+    0b00000000, 0b11000000,
+};
+
+class Meter {
+ public:
+  static constexpr uint8_t REGPLUSMINUS = 0x00;
+  static constexpr uint8_t FLAGPLUS = 0b00101011;
+  static constexpr uint8_t FLAGMINUS = 0b00101101;
+  static constexpr uint8_t REGDIG1 = 0x01;
+  static constexpr uint8_t REGDIG2 = 0x02;
+  static constexpr uint8_t REGDIG3 = 0x03;
+  static constexpr uint8_t REGDIG4 = 0x04;
+  static constexpr uint8_t REGPOINT = 0x06;
+  static constexpr uint8_t FLAGPOINT0 = 0b00110000;
+  static constexpr uint8_t FLAGPOINT1 = 0b00110001;
+  static constexpr uint8_t FLAGPOINT2 = 0b00110010;
+  static constexpr uint8_t FLAGPOINT3 = 0b00110100;
+  static constexpr uint8_t REGMODE = 0x07;
+  static constexpr uint8_t FLAGMODEHOLD = 0b00000010;
+  static constexpr uint8_t FLAGMODEREL = 0b00000100;
+  static constexpr uint8_t FLAGMODEAC = 0b00001000;
+  static constexpr uint8_t FLAGMODEDC = 0b00010000;
+  static constexpr uint8_t FLAGMODEAUTO = 0b00100000;
+  static constexpr uint8_t REGMINMAX = 0x08;
+  static constexpr uint8_t FLAGMIN = 0b00010000;
+  static constexpr uint8_t FLAGMAX = 0b00100000;
+  static constexpr uint8_t REGSCALE = 0x09;
+  static constexpr uint8_t FLAGSCALEDUTY = 0b00000010;
+  static constexpr uint8_t FLAGSCALEDIODE = 0b00000100;
+  static constexpr uint8_t FLAGSCALEBUZZ = 0b00001000;
+  static constexpr uint8_t FLAGSCALEMEGA = 0b00010000;
+  static constexpr uint8_t FLAGSCALEKILO = 0b00100000;
+  static constexpr uint8_t FLAGSCALEMILLI = 0b01000000;
+  static constexpr uint8_t FLAGSCALEMICRO = 0b10000000;
+  static constexpr uint8_t REGUNIT = 0x0a;
+  static constexpr uint8_t FLAGUNITFAHR = 0b00000001;
+  static constexpr uint8_t FLAGUNITGRAD = 0b00000010;
+  static constexpr uint8_t FLAGUNITNF = 0b00000100;
+  static constexpr uint8_t FLAGUNITHZ = 0b00001000;
+  static constexpr uint8_t FLAGUNITHFE = 0b00010000;
+  static constexpr uint8_t FLAGUNITOHM = 0b00100000;
+  static constexpr uint8_t FLAGUNITAMP = 0b01000000;
+  static constexpr uint8_t FLAGUNITVOLT = 0b10000000;
+
+  bool connected{false};
+  bool write_available{false};
+  bool is_plus{false};
+  bool low_battery{false};
+  bool overload{false};
+  bool has_reading{false};
+  uint8_t selected_button{1};
+  uint32_t last_notify_ms{0};
+
+  bool handle_notify(const std::vector<uint8_t> &data) {
+    if (data.size() > sizeof(this->raw_))
+      return false;
+    if (data.size() == 6 && data[1] >= 0xF0) {
+      memset(this->raw_, 0, sizeof(this->raw_));
+      memcpy(this->raw_, data.data(), data.size());
+      this->is_plus = true;
+      this->parse_plus_();
+    } else if (data.size() == 14 && data[12] == 0x0D && data[13] == 0x0A) {
+      memset(this->value_, 0, sizeof(this->value_));
+      memcpy(this->value_, data.data(), data.size());
+      this->is_plus = false;
+    } else {
+      ESP_LOGW(TAG, "Ignoring unexpected OWON frame length=%u", static_cast<unsigned>(data.size()));
+      return false;
+    }
+
+    this->overload = memcmp(this->value_, OVERLOAD_FRAME, sizeof(OVERLOAD_FRAME)) == 0;
+    this->display_value = this->calc_display_value_();
+    this->base_value = this->calc_base_value_();
+    this->has_reading = true;
+    this->last_notify_ms = millis();
+    return true;
+  }
+
+  void on_connect() {
+    this->connected = true;
+    this->write_available = true;
+  }
+
+  void on_disconnect() {
+    this->connected = false;
+    this->write_available = false;
+  }
+
+  float value() const { return this->display_value; }
+  float value_base() const { return this->base_value; }
+  bool negative() const { return (this->value_[REGPLUSMINUS] & FLAGMINUS) == FLAGMINUS; }
+  bool auto_range() const { return (this->value_[REGMODE] & FLAGMODEAUTO) == FLAGMODEAUTO; }
+  bool hold() const { return (this->value_[REGMODE] & FLAGMODEHOLD) == FLAGMODEHOLD; }
+  bool relative() const { return (this->value_[REGMODE] & FLAGMODEREL) == FLAGMODEREL; }
+  bool ac() const { return (this->value_[REGMODE] & FLAGMODEAC) == FLAGMODEAC; }
+  bool dc() const { return (this->value_[REGMODE] & FLAGMODEDC) == FLAGMODEDC; }
+  bool min_mode() const { return (this->value_[REGMINMAX] & FLAGMIN) == FLAGMIN; }
+  bool max_mode() const { return (this->value_[REGMINMAX] & FLAGMAX) == FLAGMAX; }
+  bool diode() const { return (this->value_[REGSCALE] & FLAGSCALEDIODE) == FLAGSCALEDIODE; }
+  bool continuity() const { return (this->value_[REGSCALE] & FLAGSCALEBUZZ) == FLAGSCALEBUZZ; }
+
+  const char *unit() const {
+    switch (this->value_[REGUNIT]) {
+      case FLAGUNITFAHR: return "°F";
+      case FLAGUNITGRAD: return "°C";
+      case FLAGUNITNF: return "nF";
+      case FLAGUNITHZ: return "Hz";
+      case FLAGUNITHFE: return "hFE";
+      case FLAGUNITOHM: return "Ω";
+      case FLAGUNITAMP: return "A";
+      case FLAGUNITVOLT: return "V";
+      default: return "";
+    }
+  }
+
+  const char *scale() const {
+    if ((this->value_[REGSCALE] & FLAGSCALEDUTY) == FLAGSCALEDUTY) return "%";
+    if ((this->value_[REGSCALE] & FLAGSCALEMEGA) == FLAGSCALEMEGA) return "M";
+    if ((this->value_[REGSCALE] & FLAGSCALEKILO) == FLAGSCALEKILO) return "k";
+    if ((this->value_[REGSCALE] & FLAGSCALEMILLI) == FLAGSCALEMILLI) return "m";
+    if ((this->value_[REGSCALE] & FLAGSCALEMICRO) == FLAGSCALEMICRO) return "µ";
+    return "";
+  }
+
+  std::string mode_text() const {
+    std::string out;
+    if (this->dc()) out += "DC ";
+    if (this->ac()) out += "AC ";
+    if (this->auto_range()) out += "AUTO ";
+    if (this->hold()) out += "HOLD ";
+    if (this->relative()) out += "REL ";
+    if (this->min_mode()) out += "MIN ";
+    if (this->max_mode()) out += "MAX ";
+    if (this->diode()) out += "DIODE ";
+    if (this->continuity()) out += "CONT ";
+    if (!out.empty()) out.pop_back();
+    return out;
+  }
+
+  std::string reading_text() const {
+    if (!this->connected) return "Disconnected";
+    if (!this->has_reading) return "Waiting for data";
+    if (this->overload) return "OL " + std::string(this->scale()) + this->unit();
+    char buf[48];
+    snprintf(buf, sizeof(buf), "%s%.4g %s%s", this->negative() ? "-" : "", std::fabs(this->display_value), this->scale(), this->unit());
+    return std::string(buf);
+  }
+
+  enum Kind { KIND_OTHER, KIND_VOLTAGE, KIND_CURRENT, KIND_RESISTANCE, KIND_FREQUENCY, KIND_CAPACITANCE, KIND_TEMP_C, KIND_TEMP_F, KIND_DUTY };
+  Kind kind() const {
+    if ((this->value_[REGSCALE] & FLAGSCALEDUTY) == FLAGSCALEDUTY) return KIND_DUTY;
+    switch (this->value_[REGUNIT]) {
+      case FLAGUNITVOLT: return KIND_VOLTAGE;
+      case FLAGUNITAMP: return KIND_CURRENT;
+      case FLAGUNITOHM: return KIND_RESISTANCE;
+      case FLAGUNITHZ: return KIND_FREQUENCY;
+      case FLAGUNITNF: return KIND_CAPACITANCE;
+      case FLAGUNITGRAD: return KIND_TEMP_C;
+      case FLAGUNITFAHR: return KIND_TEMP_F;
+      default: return KIND_OTHER;
+    }
+  }
+
+  const char *selected_button_name() const {
+    static const char *const names[] = {"SELECT", "RANGE", "HLD/LIG", "REL/BT", "HZ/DUTY", "MAX/MIN"};
+    uint8_t index = this->selected_button;
+    if (index < 1) index = 1;
+    if (index > 6) index = 6;
+    return names[index - 1];
+  }
+
+  void previous_button() {
+    if (this->selected_button > 1) this->selected_button--;
+  }
+  void next_button() {
+    if (this->selected_button < 6) this->selected_button++;
+  }
+
+  void render(esphome::display::Display &it, esphome::display::BaseFont *font,
+              esphome::display::BaseFont *value_font, int display_page = 0,
+              bool atorch_connected = false,
+              float atorch_voltage = NAN, float atorch_current = NAN, float atorch_power = NAN,
+              float atorch_capacity = NAN, float atorch_temperature = NAN)  {
+    const Color bg(0, 0, 0);
+    const Color fg(210, 210, 210);
+    // Chosen to map to a neutral dark gray in the RGB332 8-bit display palette.
+    const Color inactive(80, 80, 80);
+    const Color yellow(255, 220, 0);
+    const Color blue(0, 80, 255);
+    const Color cyan(0, 255, 255);
+    const Color magenta(255, 0, 255);
+    const Color red(255, 0, 0);
+    const Color green(0, 220, 0);
+    const Color orange(255, 165, 0);
+
+    if (display_page == 0) {
+        // --- PAGE 1: OWON Multimeter ---
+        it.fill(bg);
+        bool status_active = this->connected && this->has_reading;
+        this->draw_icon_(it, 12, 8, 16, 16, ACCU_BMP, status_active ? (this->low_battery ? red : green) : inactive);
+        this->draw_icon_(it, 46, 8, 16, 16, BLE_BMP, this->connected ? blue : inactive);
+        this->label_(it, font, 86, 8, "AUTO", status_active && this->auto_range() ? fg : inactive);
+        this->label_(it, font, 138, 8, "MAX", status_active && this->max_mode() ? red : inactive);
+        this->label_(it, font, 178, 8, "MIN", status_active && this->min_mode() ? green : inactive);
+        this->label_(it, font, 218, 8, "HOLD", status_active && this->hold() ? blue : inactive);
+        this->label_(it, font, 270, 8, "REL", status_active && this->relative() ? Color(128, 128, 0) : inactive);
+
+        this->label_(it, font, 8, 66, "DC", status_active && this->dc() ? cyan : inactive);
+        this->label_(it, font, 8, 102, "AC", status_active && this->ac() ? magenta : inactive);
+
+        if (!this->connected) {
+        this->draw_digits_(it, "----", false, inactive);
+        it.print(160, 148, font, inactive, esphome::display::TextAlign::CENTER, "scan/connect");
+        } else if (!this->has_reading) {
+        this->draw_digits_(it, "8888", false, inactive);
+        it.print(160, 148, font, inactive, esphome::display::TextAlign::CENTER, "waiting");
+        } else if (this->overload) {
+        this->draw_digits_(it, " OL ", false, fg);
+        } else {
+        char d[5];
+        d[0] = this->digit_char_(REGDIG1);
+        d[1] = this->digit_char_(REGDIG2);
+        d[2] = this->digit_char_(REGDIG3);
+        d[3] = this->digit_char_(REGDIG4);
+        d[4] = 0;
+        this->draw_digits_(it, d, this->negative(), fg);
+        this->draw_decimal_points_(it, fg);
+        }
+
+        if (status_active) {
+        std::string unit_line = std::string(this->scale()) + this->unit();
+        it.print(270, 140, font, yellow, esphome::display::TextAlign::CENTER, unit_line.c_str());
+        }
+
+        bool bargraph_active = status_active && !this->overload;
+        this->draw_bargraph_(it, bargraph_active ? this->digits_from_buffer_() : 0, bargraph_active);
+        this->draw_icon_(it, 300, 148, 16, 16, DIODE_BMP, status_active && this->diode() ? magenta : inactive);
+        this->draw_icon_(it, 300, 174, 16, 16, BUZZ_BMP, status_active && this->continuity() ? orange : inactive);
+
+        it.filled_rectangle(34, 212, 40, 24, this->write_available ? fg : inactive);
+        it.filled_rectangle(108, 212, 100, 24, this->write_available ? fg : inactive);
+        it.filled_rectangle(242, 212, 40, 24, this->write_available ? fg : inactive);
+        it.print(54, 216, font, bg, esphome::display::TextAlign::TOP_CENTER, "<");
+        it.print(158, 216, font, bg, esphome::display::TextAlign::TOP_CENTER, this->selected_button_name());
+        it.print(262, 216, font, bg, esphome::display::TextAlign::TOP_CENTER, ">");
+    } else {
+        // --- PAGE 2: Atorch DL24 DC load ---
+        it.fill(bg);
+        const Color panel_active(18, 24, 32);
+        const Color panel_inactive(12, 12, 12);
+        const Color panel_dim(10, 14, 20);
+        const Color border_active(55, 70, 86);
+        const Color border_inactive(42, 42, 42);
+        const Color white(245, 245, 245);
+        const Color dim_value(110, 110, 110);
+        const Color dim_accent(65, 65, 65);
+        const Color panel = atorch_connected ? panel_active : panel_inactive;
+        const Color border = atorch_connected ? border_active : border_inactive;
+        const Color value_color = atorch_connected ? white : dim_value;
+        const Color voltage_color = atorch_connected ? cyan : dim_accent;
+        const Color current_color = atorch_connected ? orange : dim_accent;
+        const Color power_color = atorch_connected ? yellow : dim_accent;
+        const Color temp_color = atorch_connected ? magenta : dim_accent;
+        const Color header_color = atorch_connected ? cyan : dim_value;
+
+        char voltage_text[24];
+        char current_text[24];
+        char power_text[24];
+        char capacity_text[24];
+        char temperature_text[24];
+        this->format_metric_(voltage_text, sizeof(voltage_text), atorch_voltage, "V", 2);
+        this->format_metric_(current_text, sizeof(current_text), atorch_current, "A", 3);
+        this->format_metric_(power_text, sizeof(power_text), atorch_power, "W", 2);
+        this->format_metric_(capacity_text, sizeof(capacity_text), atorch_capacity, "Ah", 3);
+        this->format_metric_(temperature_text, sizeof(temperature_text), atorch_temperature, "°C", 1);
+
+        it.filled_rectangle(0, 0, 320, 30, atorch_connected ? panel_dim : panel_inactive);
+        it.print(10, 7, font, header_color, esphome::display::TextAlign::TOP_LEFT, "ATORCH DL24");
+        if (atorch_connected) {
+          this->draw_icon_(it, 152, 7, 16, 16, BLE_BMP, blue);
+        }
+        it.print(310, 7, font, inactive, esphome::display::TextAlign::TOP_RIGHT, "DC LOAD");
+
+        this->draw_metric_card_(it, font, value_font, 10, 42, 145, 76, "VOLTAGE", voltage_text, voltage_color, panel, border, value_color);
+        this->draw_metric_card_(it, font, value_font, 165, 42, 145, 76, "CURRENT", current_text, current_color, panel, border, value_color);
+        this->draw_metric_card_(it, font, value_font, 10, 128, 145, 76, "POWER", power_text, power_color, panel, border, value_color);
+        this->draw_metric_card_(it, font, value_font, 165, 128, 145, 76, "TEMP", temperature_text, temp_color, panel, border, value_color);
+
+        it.filled_rectangle(10, 212, 300, 22, atorch_connected ? panel_dim : panel_inactive);
+        it.filled_rectangle(10, 212, 300, 1, border);
+        it.filled_rectangle(10, 233, 300, 1, border);
+        it.filled_rectangle(10, 212, 1, 22, border);
+        it.filled_rectangle(309, 212, 1, 22, border);
+        it.print(24, 216, font, inactive, esphome::display::TextAlign::TOP_LEFT, "CAPACITY");
+        it.print(306, 212, value_font, value_color, esphome::display::TextAlign::TOP_RIGHT, capacity_text);
+    }
+  }
+
+ private:
+  uint8_t raw_[14]{};
+  uint8_t value_[14]{};
+  float display_value{NAN};
+  float base_value{NAN};
+  static constexpr uint8_t OVERLOAD_FRAME[5] = {0x2B, 0x3F, 0x30, 0x3A, 0x3F};
+
+  uint16_t digits_from_buffer_() const {
+    uint16_t out = 0;
+    if (this->value_[REGDIG1] >= '0' && this->value_[REGDIG1] <= '9') out += (this->value_[REGDIG1] - '0') * 1000;
+    if (this->value_[REGDIG2] >= '0' && this->value_[REGDIG2] <= '9') out += (this->value_[REGDIG2] - '0') * 100;
+    if (this->value_[REGDIG3] >= '0' && this->value_[REGDIG3] <= '9') out += (this->value_[REGDIG3] - '0') * 10;
+    if (this->value_[REGDIG4] >= '0' && this->value_[REGDIG4] <= '9') out += (this->value_[REGDIG4] - '0');
+    return out;
+  }
+
+  float calc_display_value_() const {
+    if (this->overload) return NAN;
+
+    if (this->is_plus) {
+      uint16_t pair1 = static_cast<uint16_t>(this->raw_[0]) | (static_cast<uint16_t>(this->raw_[1]) << 8);
+      uint8_t decimal = pair1 & 0x07;
+      if (decimal >= 7) return NAN;
+
+      uint16_t pair3 = static_cast<uint16_t>(this->raw_[4]) | (static_cast<uint16_t>(this->raw_[5]) << 8);
+      bool negative = pair3 >= 0x7FFF;
+      uint16_t digits = negative ? (pair3 & 0x7FFF) : pair3;
+      float v = static_cast<float>(digits) / std::pow(10.0f, decimal);
+      return negative ? -v : v;
+    }
+
+    uint8_t decimal = 0;
+    switch (this->value_[REGPOINT] & 0x07) {
+      case 0b001: decimal = 1; break;
+      case 0b010: decimal = 2; break;
+      case 0b100: decimal = 3; break;
+      default: break;
+    }
+    float v = static_cast<float>(this->digits_from_buffer_()) / std::pow(10.0f, decimal);
+    return this->negative() ? -v : v;
+  }
+
+  float calc_base_value_() const {
+    if (std::isnan(this->display_value)) return NAN;
+    if (this->value_[REGUNIT] == FLAGUNITNF) return this->display_value * 1e-9f;
+    if ((this->value_[REGSCALE] & FLAGSCALEMEGA) == FLAGSCALEMEGA) return this->display_value * 1e6f;
+    if ((this->value_[REGSCALE] & FLAGSCALEKILO) == FLAGSCALEKILO) return this->display_value * 1e3f;
+    if ((this->value_[REGSCALE] & FLAGSCALEMILLI) == FLAGSCALEMILLI) return this->display_value * 1e-3f;
+    if ((this->value_[REGSCALE] & FLAGSCALEMICRO) == FLAGSCALEMICRO) return this->display_value * 1e-6f;
+    return this->display_value;
+  }
+
+  void parse_plus_() {
+    memset(this->value_, 0, sizeof(this->value_));
+    this->value_[5] = 0x20;
+    this->value_[12] = 0x0D;
+    this->value_[13] = 0x0A;
+
+    uint16_t pair1 = static_cast<uint16_t>(this->raw_[0]) | (static_cast<uint16_t>(this->raw_[1]) << 8);
+    uint8_t function = (pair1 >> 6) & 0x0F;
+    uint8_t scale = (pair1 >> 3) & 0x07;
+    uint8_t decimal = pair1 & 0x07;
+
+    switch (decimal) {
+      case 0: this->value_[REGPOINT] = FLAGPOINT0; break;
+      case 1: this->value_[REGPOINT] = FLAGPOINT3; break;
+      case 2: this->value_[REGPOINT] = FLAGPOINT2; break;
+      case 3: this->value_[REGPOINT] = FLAGPOINT1; break;
+      default: break;
+    }
+
+    switch (function) {
+      case 0: this->value_[REGUNIT] |= FLAGUNITVOLT; this->value_[REGMODE] |= FLAGMODEDC; break;
+      case 1: this->value_[REGUNIT] |= FLAGUNITVOLT; this->value_[REGMODE] |= FLAGMODEAC; break;
+      case 2: this->value_[REGUNIT] |= FLAGUNITAMP; this->value_[REGMODE] |= FLAGMODEDC; break;
+      case 3: this->value_[REGUNIT] |= FLAGUNITAMP; this->value_[REGMODE] |= FLAGMODEAC; break;
+      case 4: this->value_[REGUNIT] |= FLAGUNITOHM; break;
+      case 5: this->value_[REGUNIT] |= FLAGUNITNF; break;
+      case 6: this->value_[REGUNIT] |= FLAGUNITHZ; break;
+      case 7: this->value_[REGSCALE] |= FLAGSCALEDUTY; break;
+      case 8: this->value_[REGUNIT] |= FLAGUNITGRAD; break;
+      case 9: this->value_[REGUNIT] |= FLAGUNITFAHR; break;
+      case 10: this->value_[REGSCALE] |= FLAGSCALEDIODE; break;
+      case 11: this->value_[REGSCALE] |= FLAGSCALEBUZZ; break;
+      case 12: this->value_[REGUNIT] |= FLAGUNITHFE; break;
+      default: break;
+    }
+
+    switch (scale) {
+      case 2: this->value_[REGSCALE] |= FLAGSCALEMICRO; break;
+      case 3: this->value_[REGSCALE] |= FLAGSCALEMILLI; break;
+      case 5: this->value_[REGSCALE] |= FLAGSCALEKILO; break;
+      case 6: this->value_[REGSCALE] |= FLAGSCALEMEGA; break;
+      default: break;
+    }
+
+    uint16_t pair2 = static_cast<uint16_t>(this->raw_[2]) | (static_cast<uint16_t>(this->raw_[3]) << 8);
+    if (pair2 & (1 << 0)) this->value_[REGMODE] |= FLAGMODEHOLD;
+    if (pair2 & (1 << 1)) this->value_[REGMODE] |= FLAGMODEREL;
+    if (pair2 & (1 << 2)) this->value_[REGMODE] |= FLAGMODEAUTO;
+    this->low_battery = (pair2 & (1 << 3)) != 0;
+    if (pair2 & (1 << 4)) this->value_[REGMINMAX] |= FLAGMIN;
+    if (pair2 & (1 << 5)) this->value_[REGMINMAX] |= FLAGMAX;
+
+    uint16_t pair3 = static_cast<uint16_t>(this->raw_[4]) | (static_cast<uint16_t>(this->raw_[5]) << 8);
+    if (decimal < 7) {
+      uint16_t digits = pair3;
+      if (pair3 < 0x7FFF) {
+        this->value_[REGPLUSMINUS] = FLAGPLUS;
+      } else {
+        this->value_[REGPLUSMINUS] = FLAGMINUS;
+        digits = pair3 & 0x7FFF;
+      }
+      this->value_[REGDIG1] = '0' + ((digits / 1000) % 10);
+      this->value_[REGDIG2] = '0' + ((digits / 100) % 10);
+      this->value_[REGDIG3] = '0' + ((digits / 10) % 10);
+      this->value_[REGDIG4] = '0' + (digits % 10);
+    } else {
+      memcpy(this->value_, OVERLOAD_FRAME, sizeof(OVERLOAD_FRAME));
+    }
+  }
+
+  char digit_char_(uint8_t reg) const {
+    uint8_t c = this->value_[reg];
+    return (c >= '0' && c <= '9') ? static_cast<char>(c) : ' ';
+  }
+
+  void format_metric_(char *buffer, size_t size, float value, const char *unit, uint8_t decimals) const {
+    if (!std::isfinite(value)) {
+      snprintf(buffer, size, "-- %s", unit);
+      return;
+    }
+    char format[12];
+    snprintf(format, sizeof(format), "%%.%uf %%s", decimals);
+    snprintf(buffer, size, format, value, unit);
+  }
+
+  void draw_metric_card_(Display &it, esphome::display::BaseFont *label_font, esphome::display::BaseFont *value_font,
+                         int x, int y, int w, int h, const char *title, const char *value,
+                         Color accent, Color fill, Color border, Color value_color) {
+    const Color bg(0, 0, 0);
+    const Color inactive(90, 100, 110);
+    it.filled_rectangle(x, y, w, h, fill);
+    it.filled_rectangle(x, y, w, 2, accent);
+    it.filled_rectangle(x, y + h - 1, w, 1, border);
+    it.filled_rectangle(x, y, 1, h, border);
+    it.filled_rectangle(x + w - 1, y, 1, h, border);
+    it.print(x + 10, y + 9, label_font, inactive, esphome::display::TextAlign::TOP_LEFT, title);
+    it.print(x + w / 2, y + 43, value_font, value_color, esphome::display::TextAlign::CENTER, value);
+    it.filled_rectangle(x + 10, y + h - 11, w - 20, 3, bg);
+    it.filled_rectangle(x + 10, y + h - 11, w - 20, 1, accent);
+  }
+
+  void label_(Display &it, esphome::display::BaseFont *font, int x, int y, const char *text, Color color) {
+    it.print(x, y, font, color, esphome::display::TextAlign::TOP_LEFT, text);
+  }
+
+  void draw_digits_(Display &it, const char *text, bool negative, Color color) {
+    if (negative) this->draw_segment_(it, 8, 88, 26, 9, true, color);
+    constexpr int digit_x = 40;
+    constexpr int digit_y = 35;
+    constexpr int digit_w = 50;
+    constexpr int digit_h = 88;
+    constexpr int digit_distance = 64;
+    for (int i = 0; i < 4; i++) {
+      this->draw_seven_segment_(it, digit_x + i * digit_distance, digit_y, digit_w, digit_h, text[i], color);
+    }
+  }
+
+  void draw_decimal_points_(Display &it, Color color) {
+    uint8_t p = this->value_[REGPOINT];
+    if ((p & FLAGPOINT1) == FLAGPOINT1) it.filled_rectangle(95, 117, 8, 10, color);
+    if ((p & FLAGPOINT2) == FLAGPOINT2) it.filled_rectangle(159, 117, 8, 10, color);
+    if ((p & FLAGPOINT3) == FLAGPOINT3) it.filled_rectangle(223, 117, 8, 10, color);
+  }
+
+  void draw_segment_(Display &it, int x, int y, int w, int h, bool horizontal, Color color) {
+    if (horizontal) {
+      int cap = h / 2;
+      it.filled_rectangle(x + cap, y, w - 2 * cap, h +1, color);
+      it.filled_triangle(x, y + cap, x + cap, y, x + cap, y + h, color);
+      it.filled_triangle(x + w, y + cap, x + w - cap, y, x + w - cap, y + h, color);
+    } else {
+      int cap = w / 2;
+      it.filled_rectangle(x, y + cap, w +1, h - 2 * cap, color);
+      it.filled_triangle(x + cap, y, x, y + cap, x + w, y + cap, color);
+      it.filled_triangle(x + cap, y + h, x, y + h - cap, x + w, y + h - cap, color);
+    }
+  }
+
+  void draw_icon_(Display &it, int x, int y, int w, int h, const uint8_t *data, Color color) {
+    for (int row = 0; row < h; row++) {
+      for (int col = 0; col < w; col++) {
+        uint8_t byte = data[row * ((w + 7) / 8) + (col / 8)];
+        if ((byte & (0x80 >> (col % 8))) != 0) {
+          it.draw_pixel_at(x + col, y + row, color);
+        }
+      }
+    }
+  }
+
+  void draw_seven_segment_(Display &it, int x, int y, int w, int h, char ch, Color color) {
+    bool a=false,b=false,c=false,d=false,e=false,f=false,g=false;
+    switch (ch) {
+      case '0': a=b=c=d=e=f=true; break;
+      case '1': b=c=true; break;
+      case '2': a=b=d=e=g=true; break;
+      case '3': a=b=c=d=g=true; break;
+      case '4': b=c=f=g=true; break;
+      case '5': a=c=d=f=g=true; break;
+      case '6': a=c=d=e=f=g=true; break;
+      case '7': a=b=c=true; break;
+      case '8': a=b=c=d=e=f=g=true; break;
+      case '9': a=b=c=d=f=g=true; break;
+      case 'O': a=b=c=d=e=f=true; break;
+      case 'L': d=e=f=true; break;
+      case '-': g=true; break;
+      default: break;
+    }
+    int t = 10;
+    int half = h / 2;
+    int gap = 1;
+
+    int top_y = y;
+    int mid_y = y + half - t / 2;
+    int bot_y = y + h - t;
+
+    int upper_v_y = top_y + t + gap;
+    int upper_v_h = mid_y - gap - upper_v_y;
+    int lower_v_y = mid_y + t + gap;
+    int lower_v_h = bot_y - gap - lower_v_y;
+
+    if (a) this->draw_segment_(it, x + t / 2, top_y, w - t, t, true, color);
+    if (b && upper_v_h > 0) this->draw_segment_(it, x + w - t, upper_v_y, t, upper_v_h, false, color);
+    if (c && lower_v_h > 0) this->draw_segment_(it, x + w - t, lower_v_y, t, lower_v_h, false, color);
+    if (d) this->draw_segment_(it, x + t / 2, bot_y, w - t, t, true, color);
+    if (e && lower_v_h > 0) this->draw_segment_(it, x, lower_v_y, t, lower_v_h, false, color);
+    if (f && upper_v_h > 0) this->draw_segment_(it, x, upper_v_y, t, upper_v_h, false, color);
+    if (g) this->draw_segment_(it, x + t / 2, mid_y, w - t, t, true, color);
+  }
+
+  void draw_bargraph_(Display &it, uint16_t digits, bool active) {
+    const Color fg(255, 255, 255);
+    const Color inactive(80, 80, 80);
+    uint16_t mapped = active ? static_cast<uint16_t>(digits * 240 / 6000) : 0;
+    if (mapped > 240) mapped = 240;
+    for (uint16_t i = 0; i <= 240; i += 4) {
+      Color col = (active && i <= mapped) ? fg : inactive;
+      int h = (i % 40 == 0) ? 20 : ((i % 20 == 0) ? 15 : 10);
+      it.vertical_line(40 + i, 185 - h, h, col);
+    }
+    it.horizontal_line(35, 185, 250, inactive);
+  }
+};
+
+}  // namespace owon_b35t
+
+static owon_b35t::Meter owon_meter;

esphome/lab-ble-proxy.yaml

@@ -0,0 +1,573 @@
+# Derived work based on https://github.com/reaper7/M5Stack_BLE_client_Owon_B35T by reaper7.
+# AI (ChatGPT (GPT5.5), Qwen3.6) has been used to adopt the Arduino sketch to ESPHome.
+# Ported to M5Stack Core2 due to memory constraints.
+# Integrated atorch ble proxy functionality from https://github.com/syssi/esphome-atorch-dl24 by syssi.
+
+substitutions:
+  name: "lab-ble-proxy"
+  friendly_name: "Lab BLE Proxy"
+  device_description: "M5Stack Core2 BLE client for OWON B35T/B35T+ multimeter and Atorch DL24 DC load"
+  owon_mac_address: !secret owon_b35t_mac_address
+  dl24_mac_address: !secret dl24_mac_address
+  external_components_source: github://syssi/esphome-atorch-dl24@main
+  atorch_project_version: "2.1.0"
+
+esphome:
+  name: ${name}
+  friendly_name: ${friendly_name}
+  comment: ${device_description}
+  min_version: 2024.6.0
+  includes:
+    - lab-ble-proxy.h
+  on_boot:
+    priority: 850
+    then:
+      - lambda: |-
+          owon_b35t::core2_axp192_init(id(core2_i2c));
+  project:
+    name: "custom.lab-ble-proxy-m5stack-core2"
+    version: "1.0"
+
+esp32:
+  board: m5stack-core2
+  flash_size: 16MB
+  framework:
+    type: esp-idf
+    advanced:
+      minimum_chip_revision: "3.1"
+      sram1_as_iram: true
+
+psram:
+  mode: quad
+  speed: 80MHz
+
+external_components:
+  - source: ${external_components_source}
+    refresh: 0s
+
+logger:
+  level: INFO
+
+api:
+  encryption:
+    key: !secret apikey
+
+ota:
+  platform: esphome
+  password: !secret ota
+
+wifi:
+  ssid: "Voltage-legacy"
+  password: !secret voltage_legacy_psk
+  #use_address: ${name}.home
+  power_save_mode: none
+  fast_connect: on
+  min_auth_mode: WPA2
+  ap:
+    ssid: "Lab BLE Proxy Fallback Hotspot"
+    password: !secret fallback_psk
+
+captive_portal:
+
+globals:
+  - id: display_page
+    type: int
+    initial_value: "0"
+    restore_value: no
+  - id: atorch_connected
+    type: bool
+    initial_value: "false"
+    restore_value: no
+
+script:
+  - id: wake_backlight
+    mode: restart
+    then:
+      - script.stop: backlight_idle
+      - light.turn_on:
+          id: backlight
+          brightness: 100%
+  - id: backlight_idle
+    mode: restart
+    then:
+      - delay: 2min
+      - if:
+          condition:
+            lambda: |-
+              return !owon_meter.connected && !id(atorch_connected);
+          then:
+            - light.turn_on:
+                id: backlight
+                brightness: 50%
+      - delay: 3min
+      - if:
+          condition:
+            lambda: |-
+              return !owon_meter.connected && !id(atorch_connected);
+          then:
+            - light.turn_off: backlight
+
+interval:
+  - interval: 10s
+    then:
+      - lambda: |-
+          ESP_LOGI("mem", "heap free=%u min_free=%u internal_free=%u internal_largest=%u dma_free=%u dma_largest=%u psram_free=%u psram_largest=%u",
+                   static_cast<unsigned>(esp_get_free_heap_size()),
+                   static_cast<unsigned>(esp_get_minimum_free_heap_size()),
+                   static_cast<unsigned>(heap_caps_get_free_size(MALLOC_CAP_INTERNAL)),
+                   static_cast<unsigned>(heap_caps_get_largest_free_block(MALLOC_CAP_INTERNAL)),
+                   static_cast<unsigned>(heap_caps_get_free_size(MALLOC_CAP_DMA)),
+                   static_cast<unsigned>(heap_caps_get_largest_free_block(MALLOC_CAP_DMA)),
+                   static_cast<unsigned>(heap_caps_get_free_size(MALLOC_CAP_SPIRAM)),
+                   static_cast<unsigned>(heap_caps_get_largest_free_block(MALLOC_CAP_SPIRAM)));
+
+esp32_ble_tracker:
+  scan_parameters:
+    active: true
+    continuous: true
+
+ble_client:
+  - mac_address: ${owon_mac_address}
+    id: owon_ble_client
+    on_connect:
+      then:
+        - script.execute: wake_backlight
+        - lambda: |-
+            owon_meter.on_connect();
+            id(display_page) = 0;
+            id(lcd).update();
+    on_disconnect:
+      then:
+        - lambda: |-
+            owon_meter.on_disconnect();
+            if (id(display_page) == 0 && id(atorch_connected)) {
+              id(display_page) = 1;
+            }
+            id(lcd).update();
+        - if:
+            condition:
+              lambda: |-
+                return !owon_meter.connected && !id(atorch_connected);
+            then:
+              - script.execute: backlight_idle
+
+  - mac_address: ${dl24_mac_address}
+    id: atorch_ble_client
+    on_connect:
+      then:
+        - script.execute: wake_backlight
+        - lambda: |-
+            id(atorch_connected) = true;
+            id(display_page) = 1;
+            id(lcd).update();
+    on_disconnect:
+      then:
+        - lambda: |-
+            id(atorch_connected) = false;
+            if (id(display_page) == 1 && owon_meter.connected) {
+              id(display_page) = 0;
+            }
+            id(lcd).update();
+        - if:
+            condition:
+              lambda: |-
+                return !owon_meter.connected && !id(atorch_connected);
+            then:
+              - script.execute: backlight_idle
+
+atorch_dl24:
+  - id: atorch0
+    ble_client_id: atorch_ble_client
+    check_crc: false
+    throttle: 0s
+
+spi:
+  clk_pin: GPIO18
+  mosi_pin: GPIO23
+
+i2c:
+  id: core2_i2c
+  sda: GPIO21
+  scl: GPIO22
+  scan: true
+
+output:
+  - platform: template
+    type: float
+    id: lcd_backlight
+    write_action:
+      - lambda: |-
+          owon_b35t::core2_axp192_set_backlight(state);
+
+light:
+  - platform: monochromatic
+    output: lcd_backlight
+    name: "${friendly_name} Backlight"
+    id: backlight
+    restore_mode: ALWAYS_ON
+
+font:
+  - file: "fonts/Roboto-Regular.ttf"
+    id: meter_font
+    size: 15
+    glyphs:
+      [
+        " ",
+        "!",
+        "%",
+        "+",
+        "-",
+        ".",
+        "/",
+        ":",
+        "0",
+        "1",
+        "2",
+        "3",
+        "4",
+        "5",
+        "6",
+        "7",
+        "8",
+        "9",
+        "<",
+        ">",
+        "A",
+        "B",
+        "C",
+        "D",
+        "E",
+        "F",
+        "G",
+        "H",
+        "I",
+        "L",
+        "M",
+        "N",
+        "O",
+        "P",
+        "R",
+        "S",
+        "T",
+        "U",
+        "V",
+        "W",
+        "X",
+        "Y",
+        "Z",
+        "a",
+        "b",
+        "c",
+        "d",
+        "e",
+        "f",
+        "g",
+        "h",
+        "i",
+        "k",
+        "l",
+        "m",
+        "n",
+        "o",
+        "p",
+        "r",
+        "s",
+        "t",
+        "u",
+        "v",
+        "w",
+        "y",
+        "z",
+        "°",
+        "µ",
+        "Ω",
+      ]
+
+  - file: "fonts/Roboto-Medium.ttf"
+    id: atorch_value_font
+    size: 22
+    glyphs:
+      [
+        " ",
+        "+",
+        "-",
+        ".",
+        "0",
+        "1",
+        "2",
+        "3",
+        "4",
+        "5",
+        "6",
+        "7",
+        "8",
+        "9",
+        "A",
+        "C",
+        "V",
+        "W",
+        "h",
+        "°",
+      ]
+
+display:
+  - platform: mipi_spi
+    id: lcd
+    model: M5CORE2
+    update_interval: 500ms
+    lambda: |-
+      owon_meter.render(
+        it,
+        id(meter_font),
+        id(atorch_value_font),
+        id(display_page),
+        id(atorch_connected),
+        id(atorch_voltage).has_state() ? id(atorch_voltage).state : NAN,
+        id(atorch_current).has_state() ? id(atorch_current).state : NAN,
+        id(atorch_power).has_state() ? id(atorch_power).state : NAN,
+        id(atorch_capacity).has_state() ? id(atorch_capacity).state : NAN,
+        id(atorch_temperature).has_state() ? id(atorch_temperature).state : NAN
+      );
+
+touchscreen:
+  - platform: ft63x6
+    id: touch
+    display: lcd
+    on_touch:
+      then:
+        - script.execute: wake_backlight
+        - if:
+            condition:
+              lambda: |-
+                return !owon_meter.connected && !id(atorch_connected);
+            then:
+              - script.execute: backlight_idle
+
+binary_sensor:
+  - platform: touchscreen
+    touchscreen_id: touch
+    id: btn_toggle_page
+    x_min: 70
+    x_max: 250
+    y_min: 45
+    y_max: 195
+    on_press:
+      then:
+        - lambda: |-
+            id(display_page) = 1 - id(display_page);
+            id(lcd).update();
+  - platform: touchscreen
+    id: button_a
+    touchscreen_id: touch
+    x_min: 34
+    x_max: 74
+    y_min: 212
+    y_max: 240
+    internal: true
+    on_press:
+      then:
+        - lambda: |-
+            owon_meter.previous_button();
+  - platform: touchscreen
+    id: button_b
+    touchscreen_id: touch
+    x_min: 108
+    x_max: 208
+    y_min: 212
+    y_max: 240
+    internal: true
+    on_click:
+      - min_length: 50ms
+        max_length: 1500ms
+        then:
+          - logger.log:
+              level: INFO
+              format: "OWON short press: %s"
+              args: ["owon_meter.selected_button_name()"]
+          - ble_client.ble_write:
+              id: owon_ble_client
+              service_uuid: "0000fff0-0000-1000-8000-00805f9b34fb"
+              characteristic_uuid: "0000fff3-0000-1000-8000-00805f9b34fb"
+              value: !lambda |-
+                std::vector<uint8_t> data = {owon_meter.selected_button, 0x01};
+                return data;
+      - min_length: 1500ms
+        max_length: 5000ms
+        then:
+          - logger.log:
+              level: INFO
+              format: "OWON long press: %s"
+              args: ["owon_meter.selected_button_name()"]
+          - ble_client.ble_write:
+              id: owon_ble_client
+              service_uuid: "0000fff0-0000-1000-8000-00805f9b34fb"
+              characteristic_uuid: "0000fff3-0000-1000-8000-00805f9b34fb"
+              value: !lambda |-
+                uint8_t press_type = (owon_meter.selected_button == 1 || owon_meter.selected_button == 5) ? 0x01 : 0x00;
+                std::vector<uint8_t> data = {owon_meter.selected_button, press_type};
+                return data;
+  - platform: touchscreen
+    id: button_c
+    touchscreen_id: touch
+    x_min: 242
+    x_max: 282
+    y_min: 212
+    y_max: 240
+    internal: true
+    on_press:
+      then:
+        - lambda: |-
+            owon_meter.next_button();
+
+  - platform: template
+    name: "${friendly_name} OWON Connected"
+    lambda: |-
+      return owon_meter.connected;
+  - platform: template
+    name: "${friendly_name} OWON Overload"
+    lambda: |-
+      return owon_meter.overload;
+  - platform: template
+    name: "${friendly_name} OWON Low Battery"
+    lambda: |-
+      return owon_meter.low_battery;
+  - platform: template
+    name: "${friendly_name} Atorch Connected"
+    device_class: connectivity
+    lambda: |-
+      return id(atorch_connected);
+
+sensor:
+  - platform: ble_client
+    type: characteristic
+    ble_client_id: owon_ble_client
+    id: owon_notify_source
+    internal: true
+    service_uuid: "0000fff0-0000-1000-8000-00805f9b34fb"
+    characteristic_uuid: "0000fff4-0000-1000-8000-00805f9b34fb"
+    notify: true
+    update_interval: never
+    lambda: |-
+      owon_meter.handle_notify(x);
+      return owon_meter.value();
+
+  - platform: wifi_signal
+    name: "${friendly_name} WiFi Signal"
+    update_interval: 60s
+
+  - platform: atorch_dl24
+    atorch_dl24_id: atorch0
+    voltage:
+      name: "${friendly_name} Atorch Voltage"
+      id: atorch_voltage
+    current:
+      name: "${friendly_name} Atorch Current"
+      id: atorch_current
+    power:
+      name: "${friendly_name} Atorch Power"
+      id: atorch_power
+    capacity:
+      name: "${friendly_name} Atorch Capacity"
+      id: atorch_capacity
+    temperature:
+      name: "${friendly_name} Atorch Temperature"
+      id: atorch_temperature
+    dim_backlight:
+      name: "${friendly_name} Atorch Dim Backlight"
+      id: atorch_dim_backlight
+
+text_sensor:
+  - platform: template
+    name: "${friendly_name} OWON Reading"
+    update_interval: 1s
+    lambda: |-
+      return owon_meter.reading_text();
+  - platform: template
+    name: "${friendly_name} OWON Unit"
+    update_interval: 1s
+    lambda: |-
+      return std::string(owon_meter.scale()) + owon_meter.unit();
+  - platform: template
+    name: "${friendly_name} OWON Mode"
+    update_interval: 1s
+    lambda: |-
+      return owon_meter.mode_text();
+
+button:
+  - platform: atorch_dl24
+    atorch_dl24_id: atorch0
+    reset_energy:
+      name: "${friendly_name} Atorch Reset Energy"
+    reset_capacity:
+      name: "${friendly_name} Atorch Reset Capacity"
+    reset_runtime:
+      name: "${friendly_name} Atorch Reset Runtime"
+    reset_all:
+      name: "${friendly_name} Atorch Reset All"
+    usb_plus:
+      name: "${friendly_name} Atorch Plus"
+    usb_minus:
+      name: "${friendly_name} Atorch Minus"
+    setup:
+      name: "${friendly_name} Atorch Setup"
+    enter:
+      name: "${friendly_name} Atorch Enter"
+  - platform: template
+    name: "OWON SELECT"
+    id: owon_btn_select
+    on_press:
+      - ble_client.ble_write:
+          id: owon_ble_client
+          service_uuid: "0000fff0-0000-1000-8000-00805f9b34fb"
+          characteristic_uuid: "0000fff3-0000-1000-8000-00805f9b34fb"
+          value: !lambda "return std::vector<uint8_t>({1, 0x01});"
+
+  - platform: template
+    name: "OWON RANGE"
+    id: owon_btn_range
+    on_press:
+      - ble_client.ble_write:
+          id: owon_ble_client
+          service_uuid: "0000fff0-0000-1000-8000-00805f9b34fb"
+          characteristic_uuid: "0000fff3-0000-1000-8000-00805f9b34fb"
+          value: !lambda "return std::vector<uint8_t>({2, 0x01});"
+
+  - platform: template
+    name: "OWON HOLD | LIGHT"
+    id: owon_btn_hold
+    on_press:
+      - ble_client.ble_write:
+          id: owon_ble_client
+          service_uuid: "0000fff0-0000-1000-8000-00805f9b34fb"
+          characteristic_uuid: "0000fff3-0000-1000-8000-00805f9b34fb"
+          value: !lambda "return std::vector<uint8_t>({3, 0x01});"
+
+  - platform: template
+    name: "OWON RELATIVE | BT"
+    id: owon_btn_rel
+    on_press:
+      - ble_client.ble_write:
+          id: owon_ble_client
+          service_uuid: "0000fff0-0000-1000-8000-00805f9b34fb"
+          characteristic_uuid: "0000fff3-0000-1000-8000-00805f9b34fb"
+          value: !lambda "return std::vector<uint8_t>({4, 0x01});"
+
+  - platform: template
+    name: "OWON HZ | DUTY"
+    id: owon_btn_hz
+    on_press:
+      - ble_client.ble_write:
+          id: owon_ble_client
+          service_uuid: "0000fff0-0000-1000-8000-00805f9b34fb"
+          characteristic_uuid: "0000fff3-0000-1000-8000-00805f9b34fb"
+          value: !lambda "return std::vector<uint8_t>({5, 0x01});"
+
+  - platform: template
+    name: "OWON MAX | MIN"
+    id: owon_btn_maxmin
+    on_press:
+      - ble_client.ble_write:
+          id: owon_ble_client
+          service_uuid: "0000fff0-0000-1000-8000-00805f9b34fb"
+          characteristic_uuid: "0000fff3-0000-1000-8000-00805f9b34fb"
+          value: !lambda "return std::vector<uint8_t>({6, 0x01});"

recorder.yaml

@@ -1,9 +1,9 @@
-  db_url: !secret ha_recorder_dburl
+db_url: !secret ha_recorder_dburl
-  # Commit to db only every X seconds
+# Commit to db only every X seconds
-  commit_interval: 60
+commit_interval: 60
-  # Delete events and states older than 1 week
+# Delete events and states older than 1 week
-  auto_purge: true
+auto_purge: true
-  purge_keep_days: 7
+purge_keep_days: 7
 #  include:
 #    entity_globs:
 #     - sensor.rd6018_controller_*
@@ -15,10 +15,10 @@
 #       - sensor
 #       - switch
 #       - media_player
-  exclude:
+exclude:
-#    domains:
+  #    domains:
-#      - automation
+  #      - automation
-#      - updater
+  #      - updater
   entity_globs:
     - weather.zuhause_*
     - sensor.*_power_factor
@@ -36,6 +36,8 @@
     - sensor.time
     - sensor.awtrix_kitchen_current_app
     - sensor.awtrix_desk_current_app
+    - sensor.owon_b35t_multimeter_core2_owon_b35t_multimeter_core2_reading
+    - sensor.owon_b35t_multimeter_core2_owon_b35t_multimeter_core2_mode
+    - sensor.owon_b35t_multimeter_core2_owon_b35t_multimeter_core2_unit
 #    event_types:
 #      - call_service # Don't record service calls
-