homeassistant-config/esphome/owon-b35t.yaml

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.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();