Can't get accelerometer and GPS to log to SD

Hi Everyone. I'm new to the community and looking for some help.

I'm trying to build a simple GPS and accelerometer datalogger. I'm using a UNO with an Adafruit Ultimate GPS + Logging Shield and an Adafruit LIS3DH accelerometer.

I've had success writing GPS data to the SD card, using a sketch based on the Adafruit GPS shield_sdlog and parsing examples.

I've also had success reading the accelerometer using the acceldemo example sketch.

So I know that in isolation all the hardware is functional.

When I attempt to combine the operations into one sketch it gets stuck somewhere around creating the file on the SD card and Setup appears to run in a loop. It creates a series of empty text files.

I get both outputs from this if( ! logfile ):
18:16:06.730 -> Couldnt create GPSLOG03.TXT
18:16:06.730 -> Writing to GPSLOG03.TXT

Here is my code. Apologies for the mess and mashing together example sketches.

Can anyone tell me where I'm going wrong? and how I

I appreciate any suggestions and advice.

Thanks

#include <Wire.h>
#include <SPI.h>
#include <Adafruit_GPS.h>
#include <SoftwareSerial.h>
#include <SD.h>
#include <avr/sleep.h>
#include <Adafruit_LIS3DH.h>
#include <Adafruit_Sensor.h>


// I2C
Adafruit_LIS3DH lis = Adafruit_LIS3DH();



// If you're using the Adafruit GPS shield, change 
// SoftwareSerial mySerial(3, 2); -> SoftwareSerial mySerial(8, 7);
// and make sure the switch is set to SoftSerial

// If using software serial, keep this line enabled
// (you can change the pin numbers to match your wiring):
SoftwareSerial mySerial(8, 7);


File logfile;

Adafruit_GPS GPS(&mySerial);


// Set GPSECHO to 'false' to turn off echoing the GPS data to the Serial console
// Set to 'true' if you want to debug and listen to the raw GPS sentences. 
#define GPSECHO  true

/* set to true to only log to SD when GPS has a fix, for debugging, keep it false */
#define LOG_FIXONLY false 

// this keeps track of whether we're using the interrupt
// off by default!
boolean usingInterrupt = false;
void useInterrupt(boolean); // Func prototype keeps Arduino 0023 happy

// Set the pins used
#define chipSelect 10
#define ledPin 13



void setup()  {
    
  // connect at 115200 so we can read the GPS fast enough and echo without dropping chars
  // also spit it out
  Serial.begin(115200);
  Serial.println("Adafruit GPS library basic test!");

  if (! lis.begin(0x18)) {   // change this to 0x19 for alternative i2c address
    Serial.println("Couldnt start");
    while (1);
  }
  Serial.println("LIS3DH found!");
  
  lis.setRange(LIS3DH_RANGE_4_G);   // 2, 4, 8 or 16 G!
  
  Serial.print("Range = "); Serial.print(2 << lis.getRange());  
  Serial.println("G");

 pinMode(ledPin, OUTPUT);

  // make sure that the default chip select pin is set to
  // output, even if you don't use it:
  pinMode(10, OUTPUT);

  // see if the card is present and can be initialized:
  //if (!SD.begin(chipSelect, 11, 12, 13)) {
  if (!SD.begin(chipSelect)) {      // if you're using an UNO, you can use this line instead
    Serial.println("Card init. failed!");
  }
  char filename[15];
  strcpy(filename, "GPSLOG00.TXT");
  for (uint8_t i = 0; i < 100; i++) {
    filename[6] = '0' + i/10;
    filename[7] = '0' + i%10;
    // create if does not exist, do not open existing, write, sync after write
    if (! SD.exists(filename)) {
      break;
    }
  }

  logfile = SD.open(filename, FILE_WRITE);
  if( ! logfile ) {
    Serial.print("Couldnt create "); 
    Serial.println(filename);
  }
  Serial.print("Writing to "); 
  Serial.println(filename);



  // 9600 NMEA is the default baud rate for Adafruit MTK GPS's- some use 4800
  GPS.begin(9600);
  
  // uncomment this line to turn on RMC (recommended minimum) and GGA (fix data) including altitude
  GPS.sendCommand(PMTK_SET_NMEA_OUTPUT_RMCGGA);
  // uncomment this line to turn on only the "minimum recommended" data
  //GPS.sendCommand(PMTK_SET_NMEA_OUTPUT_RMCONLY);
  // For parsing data, we don't suggest using anything but either RMC only or RMC+GGA since
  // the parser doesn't care about other sentences at this time
  
  // Set the update rate
  GPS.sendCommand(PMTK_SET_NMEA_UPDATE_1HZ);   // 1 Hz update rate
  // For the parsing code to work nicely and have time to sort thru the data, and
  // print it out we don't suggest using anything higher than 1 Hz

  // Request updates on antenna status, comment out to keep quiet
  GPS.sendCommand(PGCMD_ANTENNA);

  // the nice thing about this code is you can have a timer0 interrupt go off
  // every 1 millisecond, and read data from the GPS for you. that makes the
  // loop code a heck of a lot easier!
  useInterrupt(true);

}


// Interrupt is called once a millisecond, looks for any new GPS data, and stores it
SIGNAL(TIMER0_COMPA_vect) {
  char c = GPS.read();
  // if you want to debug, this is a good time to do it!
#ifdef UDR0
  if (GPSECHO)
    if (c) UDR0 = c;  
    // writing direct to UDR0 is much much faster than Serial.print 
    // but only one character can be written at a time. 
#endif
}

void useInterrupt(boolean v) {
  if (v) {
    // Timer0 is already used for millis() - we'll just interrupt somewhere
    // in the middle and call the "Compare A" function above
    OCR0A = 0xAF;
    TIMSK0 |= _BV(OCIE0A);
    usingInterrupt = true;
  } else {
    // do not call the interrupt function COMPA anymore
    TIMSK0 &= ~_BV(OCIE0A);
    usingInterrupt = false;
  }
}

uint32_t timer = millis();
void loop()                     // run over and over again
{
  // in case you are not using the interrupt above, you'll
  // need to 'hand query' the GPS, not suggested :(
  if (! usingInterrupt) {
    // read data from the GPS in the 'main loop'
    char c = GPS.read();
    // if you want to debug, this is a good time to do it!
    if (GPSECHO)
      if (c) Serial.print(c);
  }
  
  // if a sentence is received, we can check the checksum, parse it...
  if (GPS.newNMEAreceived()) {
    // a tricky thing here is if we print the NMEA sentence, or data
    // we end up not listening and catching other sentences! 
    // so be very wary if using OUTPUT_ALLDATA and trytng to print out data
    //Serial.println(GPS.lastNMEA());   // this also sets the newNMEAreceived() flag to false
  
    if (!GPS.parse(GPS.lastNMEA()))   // this also sets the newNMEAreceived() flag to false
      return;  // we can fail to parse a sentence in which case we should just wait for another
  }

  // if millis() or timer wraps around, we'll just reset it
  if (timer > millis())  timer = millis();

  // approximately every 2 seconds or so, print out the current stats
  if (millis() - timer > 2000) { 
    timer = millis(); // reset the timer
    
    Serial.print("\nTime: ");
    Serial.print(GPS.hour, DEC); Serial.print(':');
    Serial.print(GPS.minute, DEC); Serial.print(':');
    Serial.print(GPS.seconds, DEC); Serial.print('.');
    Serial.println(GPS.milliseconds);
    Serial.print("Date: ");
    Serial.print(GPS.day, DEC); Serial.print('/');
    Serial.print(GPS.month, DEC); Serial.print("/20");
    Serial.println(GPS.year, DEC);
    Serial.print("Fix: "); Serial.print((int)GPS.fix);
    Serial.print(" quality: "); Serial.println((int)GPS.fixquality); 
    if (GPS.fix) {
      Serial.print("Location: ");
      Serial.print(GPS.latitude, 4); Serial.print(GPS.lat);
      Serial.print(", "); 
      Serial.print(GPS.longitude, 4); Serial.println(GPS.lon);
      Serial.print("Location (in degrees, works with Google Maps): ");
      Serial.print(GPS.latitudeDegrees, 4);
      Serial.print(", "); 
      Serial.println(GPS.longitudeDegrees, 4);
      
      Serial.print("Speed (knots): "); Serial.println(GPS.speed);
      Serial.print("Angle: "); Serial.println(GPS.angle);
      Serial.print("Altitude: "); Serial.println(GPS.altitude);
      Serial.print("Satellites: "); Serial.println((int)GPS.satellites);
    }

    logfile.print(GPS.hour, DEC);
    logfile.print(":");
    logfile.print(GPS.minute, DEC);
    logfile.print(":");
    logfile.print(GPS.seconds, DEC);
    logfile.print(", ");
    logfile.print(GPS.latitude, 4);
    logfile.print(", ");
    logfile.print(GPS.longitude, 4);
    logfile.print(", ");
    logfile.print(lis.x);
    logfile.print(", ");
    logfile.print(lis.y);
    logfile.print(", ");
    logfile.print(lis.z);
    logfile.println("");
    logfile.flush();
    
  }
}
  logfile = SD.open(filename, FILE_WRITE);
  if ( ! logfile )
  {
    Serial.print("Couldnt create ");
    Serial.println(filename);
  }
  Serial.print("Writing to ");
  Serial.println(filename);

If the file could not be created for some reason the program continues anyway. Is that what you intended ?

Thanks for checking it out.

That's a mistake that I've introduced when I've merged two sketches. The original sketch went to an error function when it couldn't create the filename.

Would this be causing the problem? It is still creating the files on the SD card. It doesn't seem to move on into the loop.

t doesn't seem to move on into the loop.

What do your Serial.print()s tell you is happening?

If the answer is "I don't know, because I don't have any...", then add some, to learn what the program is doing.