Battery sensor for TTGO

platformio.ini

@@ -277,3 +277,14 @@ build_flags =
   -D FIRMWARE='"macchina-a0"'
   -D SENSORS
   ${esp32.build_flags}
+
+[env:ttgo-tcell]
+extends = esp32
+lib_deps =
+  ${esp32.lib_deps}
+  ${sensors.lib_deps}
+build_flags =
+  -D TTGO_TCELL
+  -D FIRMWARE='"ttgo-tcell"'
+  -D SENSORS
+  ${esp32.build_flags}

src/Battery.cpp

@@ -8,9 +8,22 @@
 
 namespace Battery {
 #ifdef MACCHINA_A0
+const int voltageDividerResistor1 = 2200;
+const int voltageDividerResistor2 = 10000;
+const int chargingVoltage = 13200;
+const int deadVoltage = 11883;
+#define BATTERY_SENSOR
+#elif defined(TTGO_TCELL)
+const int voltageDividerResistor1 = 100000;
+const int voltageDividerResistor2 = 100000;
+const int chargingVoltage = 4150;
+const int deadVoltage = 3200;
+#define BATTERY_SENSOR
+#endif
+#ifdef BATTERY_SENSOR
 int smoothMilliVolts;
 int a0_read_batt_mv() {
-    int mv = round(((float)analogRead(GPIO_NUM_35) + 35) / 0.215);
+    int mv = analogReadMilliVolts(GPIO_NUM_35) * (voltageDividerResistor1 + voltageDividerResistor2) / voltageDividerResistor1;
     if (smoothMilliVolts)
         smoothMilliVolts = round(0.1 * (mv - smoothMilliVolts) + smoothMilliVolts);
     else
@@ -20,26 +33,32 @@ int a0_read_batt_mv() {
 #endif
 
 void Setup() {
-#if MACCHINA_A0
+#ifdef BATTERY_SENSOR
     pinMode(GPIO_NUM_35, INPUT);
 #endif
 }
 
 bool SendDiscovery() {
-#ifdef MACCHINA_A0
+#ifdef BATTERY_SENSOR
-    return sendTeleSensorDiscovery("Battery", EC_NONE, "{{ value_json.batt }}", "battery", "%") && sendTeleBinarySensorDiscovery("Charging", EC_NONE, "{{ value_json.charging }}", "battery_charging");
+    return sendTeleSensorDiscovery("Battery", EC_NONE, "{{ value_json.batt }}", "battery", "%") &&
+        sendTeleBinarySensorDiscovery("Charging", EC_NONE, "{{ value_json.charging }}", "battery_charging") &&
+        sendTeleSensorDiscovery("Battery Voltage", EC_NONE, "{{ value_json.mV }}", "voltage", "mV");
 #else
     return true;
 #endif
 }
 
 void SendTelemetry() {
-#ifdef MACCHINA_A0
+#ifdef BATTERY_SENSOR
     auto mv = a0_read_batt_mv();
     doc["mV"] = mv;
-    bool charging = (mv > 13200);
+    bool charging = (mv > chargingVoltage);
-    bool dead = (mv < 11883);
+    bool dead = (mv < deadVoltage);
+#ifdef MACCHINA_A0
     unsigned int soc = round(-13275.04 + 2.049731 * mv - (0.00007847975 * mv) * mv);
+#else
+    unsigned int soc = round(mv < 3700 ? (-64 + 0.02 * mv) : -4266.02 + 2.021295 * mv - (0.00023382077 * mv) * mv);
+#endif
     doc["batt"] = dead ? 0 : (charging ? (unsigned int)100 : max((unsigned int)0, min((unsigned int)100, soc)));
     doc["charging"] = charging ? "ON" : "OFF";
 #endif