Backup battery sensors added, small bug fixes

Author: ExperimentalAvionics

BAT.ino

@@ -0,0 +1,51 @@
+void Get_BAT() {
+// Read backup battery data
+long int Vo;
+float R2 = 10000;
+float logR1, R1, T;
+float c1 = 1.009249522e-03, c2 = 2.378405444e-04, c3 = 2.019202697e-07;
+
+long int Rv1 = 2200; // Battery voltage divider in kOhm - top resistor
+long int Rv2 = 680;  // Battery voltage divider in kOhm - bottom resistor
+
+// Battery temperature
+// low temperature threshold and high-temperature threshold in the charger controller are preset internally to 73.5%·VREF33 (0C)and 29.5%·VREF33 (48C)
+
+
+  Vo = analogRead(A7);
+  //R1 = Vo*R2/(1023-(float)Vo);  // 1023 if reference voltage is 5v
+  R1 = Vo*R2/(675-(float)Vo);  // 675 if reference voltage is 3.3v
+  logR1 = log(R1);
+  T = (1.0 / (c1 + c2*logR1 + c3*logR1*logR1*logR1)); // https://en.wikipedia.org/wiki/Steinhart%E2%80%93Hart_equation
+  T = T - 273.15;
+  //T = T * 9.0 / 5.0 + 32.0; // Fahrenheit conversion
+
+  BAT_Temperature = T;
+
+  Vo = analogRead(A6);
+  Vo = Vo*5000/1023;
+  Vo = Vo*(Rv1+Rv2)/Rv2;
+
+  BAT_Voltage = Vo; // battery voltage in millivolts
+
+
+
+// status information
+// ACOK Valid Input Supply Indicator. Open drain output. Add pull-up resistor. Logic LOW indicates the presence of a valid input supply.
+// CHGOK Charging Status Indicator. Open drain output. Add pull-up resistor. Logic LOW indicates normal charging. Logic HIGH indicates either a completed charge process or suspended
+// process because of some fault.
+
+  BAT_Status = !digitalRead(9); // ACOK
+  BAT_Status = BAT_Status*2 + !digitalRead(7); // CHGOK 
+
+
+/*
+  Serial.print("BAT_Voltage = ");
+  Serial.println(BAT_Voltage);
+  Serial.print("BAT_Temperature = ");
+  Serial.println(BAT_Temperature);
+  Serial.print("BAT_Status = ");
+  Serial.println(BAT_Status);
+*/  
+  
+  }

EFIS_ModuleA.ino

@@ -51,6 +51,11 @@ int i = 0;
   int OAT = 0;
   int Humidity = 0;
 
+// Backup battery data
+  unsigned int BAT_Voltage = 0;
+  byte BAT_Status = 0;
+  int BAT_Temperature = 0;
+
   unsigned int Airspeed = 0;
 //  int VerticalSpeed = 0;
   int AoA = 0;
@@ -77,16 +82,20 @@ const unsigned int CAN_AoA_Msg_ID = 41; // CAN Msg ID in DEC
 const unsigned int CAN_OAT_Msg_ID = 42; // CAN Msg ID in DEC
 const unsigned int CAN_RAW_Msg_ID = 43; // CAN Msg ID in DEC
 const unsigned int CAN_QNH_Msg_ID = 46; // CAN Msg ID in DEC
+const unsigned int CAN_BAT_Msg_ID = 86; // CAN Msg ID in DEC
 const unsigned int CAN_Air_Period = 300; // How often message sent in milliseconds
 const unsigned int CAN_AoA_Period = 200; // How often message sent in milliseconds
 const unsigned int CAN_OAT_Period = 2000; // How often message sent in milliseconds
 const unsigned int CAN_RAW_Period = 500; // How often message sent in milliseconds
 const unsigned int CAN_QNH_Period = 5000;
+const unsigned int CAN_BAT_Period = 3000; // How often message sent in milliseconds
 unsigned long CAN_Air_Timestamp = 0; // when was the last message sent
 unsigned long CAN_AoA_Timestamp = 0; // when was the last message sent
 unsigned long CAN_OAT_Timestamp = 0; // when was the last message sent
 unsigned long CAN_RAW_Timestamp = 0; // when was the last message sent
 unsigned long CAN_QNH_Timestamp = 0;
+unsigned long CAN_BAT_Timestamp = 0; // when was the last message sent
+
 int QNH_MemOffset = 0;
 
 unsigned char len = 0;
@@ -98,6 +107,8 @@ MCP_CAN CAN(CAN_CS_PIN);                                    // Set CS pin
 void setup()
 {
  Wire.begin(); // wake up I2C bus
+ pinMode(7, INPUT_PULLUP);
+ pinMode(9, INPUT_PULLUP);
  delay (50);
  Serial.begin(115200);
 
@@ -238,15 +249,40 @@ if (millis() > CAN_RAW_Timestamp + CAN_RAW_Period + random(0, 50)) {
 // QNH is stored in this module as well as Display modules where it can be changed.
 // Latest change in the Display module overwrites the QNH value on all devices.
 // The QNH gets re-broadcasted in case one of the units goes down 
-if (millis() > CAN_QNH_Timestamp + CAN_QNH_Period) {
+// !!!!!!!!!!!!!! QNH re-broadcasting has been removed as unnnecesary !!!!!!!!!!!!!
+// !!!!!!!!!!!! re-broadcasting code left commented out pending testing !!!!!!!!!!!
+/* if (millis() > CAN_QNH_Timestamp + CAN_QNH_Period) {
 
  Send_QNH();
  CAN_QNH_Timestamp = millis();
 
 }
+*/
+
+/*
+ * The section below does not belong to Module A (air pressure data)
+ * The data below is most suitable for EMS module
+ * EMS module does not have analog inputs left available
+ * so the backup battery data will be capured bu this module until EMS module expanded (one day)
+*/
 
+// Send Backup Battery data
+if (millis() > CAN_BAT_Timestamp + CAN_BAT_Period + random(0, 100)) {
+  
+  Get_BAT();
+  
+  canMsg[0] = BAT_Voltage;
+  canMsg[1] = BAT_Voltage >> 8;
 
+  canMsg[2] = BAT_Status;
+
+  canMsg[3] = BAT_Temperature;
+
+  CAN.sendMsgBuf(CAN_BAT_Msg_ID, 0, 4, canMsg); 
+
+  CAN_BAT_Timestamp = millis();
 
+}
 
 
 }

README.md

@@ -8,6 +8,10 @@ Unzip libraries.zip to the "libraries" folder in your Arduino environment.
 
 ## Release Notes: ##
 
+### 2023-06-27 ###
+* Removed QNH re-broadcasting as unnecessary
+* Added code to read and broadcast backup battery data from CAN HUB ver 3
+
 ### 2021-06-08 ###
 * Bug fix for QNH setting