Add option to monitor battery level

config.h

@@ -104,3 +104,8 @@
 #define CFG_PTT_PIN           12      // PTT pin
 #define CFG_PTT_TX_DELAY_MS   50      // delay between relay switching ON and transmission startup
 #define CFG_PTT_TX_TAIL_MS    10      // delay between stopping transmission and relay switching OFF
+
+// Enable modem telemetry
+#define CFG_TLM_ENABLE        false   // enable modem battery monitor
+#define CFG_TLM_BAT_MON_PIN   36      // battery ADC pin
+#define CFG_TLM_BAT_MON_CAL   0.37f   // calibration coefficient

esp32_loraprs.ino

@@ -94,6 +94,11 @@ void initializeConfig(LoraPrs::Config &cfg) {
   cfg.PttPin = CFG_PTT_PIN;
   cfg.PttTxDelayMs = CFG_PTT_TX_DELAY_MS;
   cfg.PttTxTailMs = CFG_PTT_TX_TAIL_MS;
+
+  // battery level monitor
+  cfg.TlmEnable = CFG_TLM_ENABLE;
+  cfg.TlmBatMonPin = CFG_TLM_BAT_MON_PIN;
+  cfg.TlmBatMonCal = CFG_TLM_BAT_MON_CAL;
 }
 
 LoraPrs::Service loraPrsService;

kiss_processor.h

@@ -39,6 +39,7 @@ protected:
     SetHardware = 0x06,
     SignalReport = 0x07,
     RebootRequested = 0x08,
+    Telemetry = 0x09,
     NoCmd = 0x80
   };
 
@@ -77,7 +78,7 @@ protected:
 
 private:
   bool receiveByte(byte rxByte);
-  bool receiveByteRaw(byte rxByte);
+  bool receiveByteRaw(byte rxByte); 
   bool receiveByteKiss(byte rxByte);
 
   void processData(byte rxByte);

loraprs_config.h

@@ -75,6 +75,11 @@ struct Config
   int PttPin;                           // esp pin to set high on transmit
   int PttTxDelayMs;                     // ptt tx delay
   int PttTxTailMs;                      // ptt tx tail
+
+  // enable modem telemetry
+  bool TlmEnable;                 // true - enable modem telemetry event
+  int TlmBatMonPin;                        // battery monitor pin
+  float TlmBatMonCal;                      // calibration coefficient
 };
 
 } // LoraPrs

loraprs_service.cpp

@@ -87,6 +87,12 @@ void Service::setup(const Config &conf)
     LOG_INFO("External PTT is enabled");
     pinMode(config_.PttPin, OUTPUT);
   }
+
+  // telemetry event
+  if (config_.TlmEnable) {
+    LOG_INFO("Telemetry event is enabled");
+    telemetryTimer_.every(CfgTelemetryPeriodMs, sendModemTelemetryTimer, this);
+  }
 }
 
 void Service::printConfig() {
@@ -301,6 +307,11 @@ void Service::loop()
       csmaSlotTimePrev_ = currentTime;
     }
   }
+
+  // timers
+  if (config_.TlmEnable) {
+    telemetryTimer_.tick();
+  }
   delay(CfgPollDelayMs);
 }
 
@@ -455,6 +466,22 @@ void Service::sendSignalReportEvent(int rssi, float snr)
   sendRigToSerial(Cmd::SignalReport, (const byte *)&signalReport, sizeof(SignalReport));
 }
 
+bool Service::sendModemTelemetryTimer(void *param)
+{
+  ((Service *)param)->sendModemTelemetry();
+  return true;
+}
+
+void Service::sendModemTelemetry()
+{
+  float batVoltage = 2 * analogRead(config_.TlmBatMonPin) * (3.3 / 4096.0) + config_.TlmBatMonCal;
+  LOG_INFO("Battery voltage", batVoltage);
+
+  struct Telemetry telemetry;
+  telemetry.batteryVoltage = htobe16(100 * batVoltage);
+  sendRigToSerial(Cmd::Telemetry, (const byte *)&telemetry, sizeof(Telemetry));
+}
+
 bool Service::sendAx25PayloadToRig(const AX25::Payload &payload)
 {
   int bytesWritten;

loraprs_service.h

@@ -1,4 +1,4 @@
-#ifndef LORAPRS_SEVICE_H
+#ifndef LORAPRS_SERVICE_H
 #define LORAPRS_SERVICE_H
 
 #include <Arduino.h>
@@ -16,6 +16,7 @@
 
 #include <WiFi.h>
 #include <endian.h>
+#include <arduino-timer.h>
 
 #include "BluetoothSerial.h"
 #include "ble_serial.h"
@@ -54,6 +55,8 @@ private:
   void onAprsisDataAvailable();
 
   void sendSignalReportEvent(int rssi, float snr);
+  static bool sendModemTelemetryTimer(void *param);
+  void sendModemTelemetry();
   void sendPeriodicBeacon();
   void sendToAprsis(const String &aprsMessage);
   bool sendAx25PayloadToRig(const AX25::Payload &payload);
@@ -110,14 +113,20 @@ private:
     int16_t rssi;
     int16_t snr;
   } __attribute__((packed));
+
+  struct Telemetry {
+    int16_t batteryVoltage;
+  } __attribute__((packed));
   
 private:
-  const String CfgLoraprsVersion = "LoRAPRS 1.0.5";
+  const String CfgLoraprsVersion = "LoRAPRS 1.0.6";
 
   // processor config
   const int CfgConnRetryMs = 500;             // connection retry delay, e.g. wifi
   const int CfgPollDelayMs = 20;              // main loop delay
   const int CfgConnRetryMaxTimes = 10;        // number of connection retries
+  const int CfgTelemetryPeriodMs = 30000;     // how often to send telemetry event
+
   static const int CfgMaxPacketSize = 256;    // maximum packet size
   static const int CfgRadioQueueSize = 1024;  // radio queue size
 
@@ -168,6 +177,9 @@ private:
   std::shared_ptr<WiFiServer> kissServer_;
   WiFiClient kissConnnection_;
   bool isKissClientConnected_;
+
+  // modem telemetry
+  Timer<1> telemetryTimer_;
 };
 
 } // LoraPrs