added Coin Battery logging

Use command "dump gps" for a CSV file of battery voltage over time

Griduino.ino

@@ -834,6 +834,7 @@ void setup() {
 //uint32_t prevTimeGPS = millis();
 elapsedSeconds saveGpsTimer;          // timer to process and save the current GPS location
 elapsedSeconds autoLogTimer;          // timer to save GPS trail periodically no matter what
+elapsedSeconds batteryTimer;          // timer to log the coin battery voltage
 uint32_t prevTimeBaro = millis();
 time_t prevTimeRTC = 0;               // timer to print RTC to serial port (1 second)
 elapsedMillis displayClockTimer;      // timer to update time-of-day display (1 second)
@@ -856,6 +857,7 @@ const uint32_t GPS_AUTOSAVE_INTERVAL = SECS_PER_10MIN; // seconds between saving
 //const int BAROMETRIC_PROCESS_INTERVAL = 15*60*1000;  // fifteen minutes in milliseconds
 const uint LOG_PRESSURE_INTERVAL = 15*60*1000;   // 15 minutes, in milliseconds
 const uint LOS_ANNOUNCEMENT_INTERVAL = SECS_PER_5MIN * 1000;   // msec between LOS announcements
+const int  LOG_COIN_BATTERY_INTERVAL = 60;       // seconds between logging the coin battery voltage
 
 void loop() {
 
@@ -1033,6 +1035,21 @@ void loop() {
     }
   }
 
+  // periodically log the coin battery's voltage 
+  // todo: sensor exists only on PCB v11+
+  if (batteryTimer > LOG_COIN_BATTERY_INTERVAL) {
+    batteryTimer = 0;
+
+    const float analogRef     = 3.3;    // analog reference voltage
+    const uint16_t analogBits = 1024;   // ADC resolution is 10 bits
+
+    int coin_adc       = analogRead(BATTERY_ADC);
+    float coin_voltage = (float)coin_adc * analogRef / analogBits;
+    logger.info("Coin battery = %s", coin_voltage, 3);
+
+    trail.rememberBAT(coin_voltage);
+  }
+
   // log GPS position every few minutes, to keep track of lingering in one spot
   if (autoLogTimer > GPS_AUTOSAVE_INTERVAL) {
     autoLogTimer = 0;

constants.h

@@ -212,8 +212,9 @@ struct FunctionButton {
 #define rFIRSTVALIDTIME      "TIM"
 #define rLOSSOFSIGNAL        "LOS"
 #define rACQUISITIONOFSIGNAL "AOS"
+#define rCOINBATTERYVOLTAGE  "BAT"
 #define rRESET               "\0\0\0"
-#define rVALIDATE            rGPS rPOWERUP rPOWERDOWN rFIRSTVALIDTIME rLOSSOFSIGNAL rACQUISITIONOFSIGNAL
+#define rVALIDATE            rGPS rPOWERUP rPOWERDOWN rFIRSTVALIDTIME rLOSSOFSIGNAL rACQUISITIONOFSIGNAL rCOINBATTERYVOLTAGE
 
 // Breadcrumb data definition for circular buffer
 class Location {
@@ -222,7 +223,7 @@ class Location {
   PointGPS loc;            // has-a lat/long, degrees
   time_t timestamp;        // has-a GMT time
   uint8_t numSatellites;   // number of satellites in use (not the same as in view)
-  float speed;             // current speed over ground in MPH
+  float speed;             // current speed over ground in MPH (or coin battery voltage)
   float direction;         // direction of travel, degrees from true north
   float altitude;          // altitude, meters above MSL
 public:
@@ -269,6 +270,10 @@ class Location {
     return (strncmp(recordType, rACQUISITIONOFSIGNAL, sizeof(recordType)) == 0);
   }
 
+  bool isCoinBatteryVoltage() const {
+    return (strncmp(recordType, rCOINBATTERYVOLTAGE, sizeof(recordType)) == 0);
+  }
+
   // print ourself - a sanity check
   void printLocation(const char *comment = NULL) {   // debug
     Serial.println(". Rec, ___Date___ __Time__, (__Lat__, __Long__=), Alt, Spd, Dir, Sats");

examples/Coin_Battery/Coin_Battery.ino

@@ -0,0 +1,126 @@
+#line 1 "C:\\Users\\barry\\Documents\\Arduino\\Griduino\\examples\\Coin_Battery\\Coin_Battery.ino"
+// Please format this file with clang before check-in to GitHub
+/*
+  Coin_Battery -- simple voltage measurement of coin battery
+
+  Version history:
+      2024-02-14 written for Griduino both pcb v4 and v12
+
+  Software: Barry Hansen, K7BWH, barry@k7bwh.com, Seattle, WA
+  Hardware: John Vanderbeck, KM7O, Seattle, WA
+
+  This example code is in the public domain.
+*/
+
+#include <Arduino.h>
+#include <Wire.h>
+#include <Adafruit_I2CDevice.h>
+
+const float analogRef     = 3.3;    // default analog reference voltage
+const uint16_t analogBits = 1024;   // default ADC resolution bits
+int pcbVersion            = 0;      // default to unknown PCB
+
+#line 22 "C:\\Users\\barry\\Documents\\Arduino\\Griduino\\examples\\Coin_Battery\\Coin_Battery.ino"
+bool detectDevice(int address);
+#line 66 "C:\\Users\\barry\\Documents\\Arduino\\Griduino\\examples\\Coin_Battery\\Coin_Battery.ino"
+int pcb_detect();
+#line 80 "C:\\Users\\barry\\Documents\\Arduino\\Griduino\\examples\\Coin_Battery\\Coin_Battery.ino"
+void setup();
+#line 93 "C:\\Users\\barry\\Documents\\Arduino\\Griduino\\examples\\Coin_Battery\\Coin_Battery.ino"
+void loop();
+#line 22 "C:\\Users\\barry\\Documents\\Arduino\\Griduino\\examples\\Coin_Battery\\Coin_Battery.ino"
+bool detectDevice(int address) {
+  // https://github.com/adafruit/Adafruit_BusIO/blob/master/Adafruit_I2CDevice.h
+  Adafruit_I2CDevice device(address);
+  if (device.detected()) {
+    Serial.print("I2C device found at address 0x");
+    if (address < 16)
+      Serial.print("0");
+    Serial.println(address, HEX);
+
+    delay(10);
+    device.end();
+    return true;
+  } else {
+    delay(10);
+    device.end();
+    return false;
+  }
+
+  /* *****
+  // https://learn.adafruit.com/scanning-i2c-addresses/arduino
+  byte error;
+
+  // The i2c_scanner uses the return value of the Write.endTransmission
+  // to see if a device did acknowledge the address.
+  //WIRE.beginTransmission(address);
+  //error = WIRE.endTransmission();
+
+  if (error == 0) {
+    Serial.print("I2C device found at address 0x");
+    if (address < 16)
+      Serial.print("0");
+    Serial.println(address, HEX);
+    return true;
+
+  } else if (error == 4) {
+    Serial.print("Unknown error at address 0x");
+    if (address < 16)
+      Serial.print("0");
+    Serial.println(address, HEX);
+  }
+  return false;
+  ***** */
+}
+
+int pcb_detect() {
+  Serial.println("Scanning...");
+  bool i00 = detectDevice(0x00);
+  bool i01 = detectDevice(0x01);
+  bool i3E = detectDevice(0x3E);
+  bool i77 = detectDevice(0x77);
+
+  if (!i3E || !i77) {
+    return 4;
+  } else {
+    return 11;
+  }
+}
+
+void setup() {
+  Serial.begin(115200);
+
+  // Wait for Serial port to open
+  while (!Serial) {
+    delay(10);
+  }
+  delay(500);
+  Serial.println(__FILE__);
+  Serial.println("Griduino Coin Battery Measurement");
+  Serial.println("Sampled resolution is (3.3v)/1024 = 3 mV");
+}
+
+void loop() {
+  Serial.println("");
+  pcbVersion = pcb_detect();
+  Serial.print("PCB version = ");
+  Serial.println(pcbVersion);
+
+  int coin_adc       = analogRead(A2);
+  float coin_voltage = (float)coin_adc * analogRef / analogBits;
+
+  Serial.print("Coin battery sampled = ");
+  Serial.println(coin_adc);
+
+  Serial.print("Coin battery voltage = ");
+  Serial.print(coin_voltage);
+  Serial.print(" volts");
+
+  if (coin_voltage < 2.8) {
+    Serial.println(" Warning! Low voltage!");
+  } else {
+    Serial.println("");
+  }
+
+  delay(4000);
+}

hardware.h

@@ -118,10 +118,8 @@ On-board lights:
 #define PIN_SPEAKER DAC0   // uses DAC
 #endif
 
-// ---------- Battery voltage sensor
-#if defined(ARDUINO_ADAFRUIT_FEATHER_RP2040)
-#define BATTERY_ADC A1
-#endif
+// ---------- Coin battery voltage sensor
+#define BATTERY_ADC A2
 
 // ---------- Feather RP2040 onboard led
 #if defined(ARDUINO_ADAFRUIT_FEATHER_RP2040)

logger.h

@@ -39,6 +39,9 @@ enum {
 #include <Arduino.h>   // for "strncpy" and others
 #include "logger.h"    // conditional printing to Serial port
 
+// extern
+void floatToCharArray(char *result, int maxlen, double fValue, int decimalPlaces);   // Griduino.ino
+
 class Logger {
 
 public:
@@ -117,6 +120,15 @@ class Logger {
       Serial.println(msg);
     }
   }
+  void info(const char *pText, const float value1, const int decimalPlaces) {   // one format string containing %s, one float, one int
+    if (print_info) {
+      char msg[256];
+      char sFloat[8];
+      floatToCharArray(sFloat, sizeof(sFloat), value1, decimalPlaces);
+      snprintf(msg, sizeof(msg), pText, sFloat);
+      Serial.println(msg);
+    }
+  }
   void info(const char *pText, const int value1, const int value2) {   // one format string, two numbers
     if (print_info) {
       char msg[256];

model_breadcrumbs.cpp

@@ -94,6 +94,12 @@ void Breadcrumbs::dumpHistoryGPS(int limit) {
       snprintf(out, sizeof(out), "%d, %s, %s, %s, %s, %s, %s, %s, %s, %s, %d",
                ii, item->recordType, sDate, sTime, grid6, sLat, sLng, sAltitude, sSpeed, sDirection, nSats);
 
+    } else if (item->isCoinBatteryVoltage()) {
+      char sVolts[12];
+      floatToCharArray(sVolts, sizeof(sVolts), item->speed, 2);
+      snprintf(out, sizeof(out), "%d, %s, %s, %s, %s",
+               ii, item->recordType, sDate, sTime, sVolts);
+
     } else {
       // format for "should not happen" messages
       snprintf(out, sizeof(out), "%d, --> Type '%s' unknown: ", ii, item->recordType);

model_breadcrumbs.h

@@ -8,7 +8,7 @@
 
   Breadcrumb trail strategy:
             This is a "model" of the Model-View-Controller design pattern.
-            As such, it contains the data for holding all the breadcrumbs  and is a
+            As such, it contains the data for holding all the breadcrumbs and is a
             low-level component with minimal side effects and few dependencies.
 
             This "Breadcrumbs" object will just only manage itself.
@@ -18,7 +18,7 @@
             We don't reach into the "model" from here and tell it what to do.
             If the controller tells us to save to file, don't tell the "model" to do anything.
 
-            When should the controller should remember a new breadcrumb?
+            When should the controller tell us to remember a new breadcrumb?
             1. Every ten minutes
             2. When we drive a visible distance on the screen
             3. When we drive into a new 6-digit grid square (todo)
@@ -166,6 +166,13 @@ class Breadcrumbs {
     remember(vLoc);
   }
 
+  void rememberBAT(float volts) {   // save "coin battery voltage" in history buffer
+    // all we have to do is save a float, so re-use the "speed" field
+    Location bat{rCOINBATTERYVOLTAGE, noLocation, now(), noSatellites, volts, noDirection, noAltitude};
+    strncpy(bat.recordType, rCOINBATTERYVOLTAGE, sizeof(bat.recordType));
+    remember(bat);
+  }
+
   void rememberFirstValidTime(time_t vTime, uint8_t vSats) {   // save "first valid time received from GPS"
     // "first valid time" can happen _without_ a satellite fix,
     // so the only data stored is the GMT timestamp