Add Wi-Fi roaming and connection status display

esphome/energymonitor.yaml

@@ -22,10 +22,18 @@ network:
   enable_ipv6: true
 
 wifi:
-  ssid: "Voltage-legacy"
+  networks:
-  password: !secret voltage_legacy_psk
+    - ssid: "Voltage-legacy"
+      password: !secret voltage_legacy_psk
+      priority: 10
+    - ssid: "Moppelkotze"
+      password: !secret moppelkotze_psk
+      priority: 5
+  on_connect:
+    - lambda: id(wifi_connected) = true;
+  on_disconnect:
+    - lambda: id(wifi_connected) = false;
   power_save_mode: high
-  fast_connect: on
   min_auth_mode: WPA2
   ap:
     ssid: "Energymonitor Fallback Hotspot"
@@ -92,6 +100,25 @@ display:
     lambda: |-
       it.fill(Color::BLACK);
 
+      // Four bars show RSSI quality; a crossed outline means Wi-Fi is disconnected.
+      if (id(wifi_connected)) {
+        int bars = 1;
+        if (id(wifi_rssi).has_state()) {
+          const float rssi = id(wifi_rssi).state;
+          bars = rssi >= -55 ? 4 : rssi >= -67 ? 3 : rssi >= -75 ? 2 : 1;
+        }
+        for (int index = 0; index < 4; index++) {
+          const int height = 5 + index * 5;
+          const Color color = index < bars ? Color(64, 255, 64) : Color(48, 48, 48);
+          it.filled_rectangle(290 + index * 5, 30 - height, 3, height, color);
+        }
+      } else {
+        const Color disconnected_color = Color(255, 80, 80);
+        it.rectangle(290, 10, 19, 19, disconnected_color);
+        it.line(290, 10, 308, 28, disconnected_color);
+        it.line(308, 10, 290, 28, disconnected_color);
+      }
+
       if (id(page_index) == 0) {
         it.printf(12, 12, id(font_small), Color::WHITE, "Netzleistung");
         if (id(grid_power).has_state()) {
@@ -130,8 +157,16 @@ globals:
     type: int
     restore_value: true
     initial_value: '0'
+  - id: wifi_connected
+    type: bool
+    restore_value: false
+    initial_value: 'false'
 
 sensor:
+  - platform: wifi_signal
+    id: wifi_rssi
+    internal: true
+    update_interval: 10s
   - platform: homeassistant
     id: grid_power
     entity_id: sensor.netzleistung