PA1010D GPS Sensor to LCD Problem

Using a PA1010 GPS sensor from Adafruit.

My code is as follows:

// Test code for Adafruit GPS That Support Using I2C
//
// This code shows how to parse data from the I2C GPS
//
// Pick one up today at the Adafruit electronics shop
// and help support open source hardware & software! -ada

#include <Adafruit_GPS.h>
#include <Wire.h>
#include <LiquidCrystal_I2C.h>

// Connect to the GPS on the hardware I2C port
Adafruit_GPS GPS(&Wire);
// set the LCD address to 0x27 for a 20 chars and 4 line display
LiquidCrystal_I2C lcd(0x27, 20, 4); // set the LCD address to 0x27 for a 20 chars and 4 line display

// 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 false

uint32_t timer = millis();


void setup()
{
  //while (!Serial);  // uncomment to have the sketch wait until Serial is ready

  // connect at 115200 so we can read the GPS fast enough and echo without dropping chars
  // also spit it out
  Serial.begin(9600);
  Serial.println("Adafruit I2C GPS library basic test!");
  //Initialize LCD
  lcd.init();
  lcd.init();
  lcd.backlight();

  // 9600 NMEA is the default baud rate for Adafruit MTK GPS's- some use 4800
  GPS.begin(0x10);  // The I2C address to use is 0x10
  // 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);

  delay(1000);

  // Ask for firmware version
  GPS.println(PMTK_Q_RELEASE);
}

void loop() // run over and over again
{
  // 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 trying 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
  }

  // approximately every 2 seconds or so, print out the current stats
  if (millis() - timer > 2000) {
    timer = millis(); // reset the timer
    Serial.print("\nTime: ");
    if (GPS.hour < 10) {
      Serial.print('0');
    }
    Serial.print(GPS.hour, DEC); Serial.print(':');
    if (GPS.minute < 10) {
      Serial.print('0');
    }
    Serial.print(GPS.minute, DEC); Serial.print(':');
    if (GPS.seconds < 10) {
      Serial.print('0');
    }
    Serial.print(GPS.seconds, DEC); Serial.print('.');
    if (GPS.milliseconds < 10) {
      Serial.print("00");
    } else if (GPS.milliseconds > 9 && GPS.milliseconds < 100) {
      Serial.print("0");
    }
    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("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);

      // LCD Data
      lcd.clear();
      lcd.backlight();
      lcd.setCursor(0, 0);
      lcd.print(" LAT: ");
      lcd.print(GPS.latitude, 4);
      lcd.print(GPS.lat);
      lcd.setCursor(0, 1);
      lcd.print(" LON: ");
      lcd.print(GPS.longitude, 4);
      lcd.print(GPS.lon);
      lcd.setCursor(0, 2);
      lcd.print("Altitude: "); lcd.print(GPS.altitude * 3.28084); lcd.print(" Ft.");
      lcd.setCursor(0, 3);
      lcd.print("Satellites: "); lcd.print((int)GPS.satellites);


    }
  }
}
}

I have tried a few things with the code but the problem with the display persist. I have even tried a different LCD which I know to be good. The above code yields:

Rather than "LON" I am getting ".ON" so I tried to modify the code:

// LCD Data
       lcd.clear();
       lcd.backlight();
       lcd.setCursor(0,0);
       lcd.print(" LAT: ");
       lcd.print(GPS.latitude, 4); 
       lcd.print(GPS.lat);
       lcd.setCursor(0,1);
       lcd.print(" LON: ");
       lcd.print(GPS.longitude, 4); 
       lcd.print(GPS.lon);
       lcd.setCursor(0,2);
       lcd.print("Altitude: "); lcd.print(GPS.altitude*3.28084);lcd.print(" Ft.");
       lcd.setCursor(0,3);
       lcd.print("Satellites: "); lcd.print((int)GPS.satellites);


I keep getting what looks to be a decimal point preceding the data. I even tried starting the line one character in but I get pretty much the same. A few times after a reset things worked but it quickly reverts back to what we see here. The data is accurate enough. During the day I get 6 or 7 satellites and after dark I get as many as 13. The serial monitor data looks fine:

GPS3

Anyone familiar with this quirk? I can't figure it out.

Thank You
Ron

Please edit your post to add code tags properly. Select the code and use the "</>" editor button.

Better, first use CTRL-T in the Arduino editor to format and indent it properly, and repost, as it will be much easier to read.

Sorry, I was having an argument with the code tags. I tried manually putting in tags which obviously did not go well :(.

Thanks
Ron

Much better, thanks. I'll make a wild guess: try a short delay after the setCursor() call. The display processor is slow, and may not be quite ready for the next character.

       lcd.setCursor(0,1);
       delay(1);
       lcd.print("LON: ");

Tried 1 and 10 millisec delays. No joy. Have also tried different baud rates which I doubt would matter.

Thank You
Ron

The only other thing I can think of is to put a very significant debug delay after every lcd.print() statement or other lcd call, so you can watch to see exactly when the period appears.

I'll get back to it tomorrow and thank you for more suggestions. Never ran into this before so sort of strange. I am expecting a coin battery for the real time clock in the GPS module but can't figure how that would matter. Figures also with all the batteries we have in this house I didn't have one for the module. So ordered a bunch from Amazon. I should have checked when I was in the drugstore today. A common CR1220 battery, sheese. :slight_smile:

Thanks Again
Ron

I got it after coming close to insanity. My revised code looks like this:

// Test code for Adafruit GPS That Support Using I2C
//
// This code shows how to parse data from the I2C GPS
//
// Pick one up today at the Adafruit electronics shop
// and help support open source hardware & software! -ada

#include <Adafruit_GPS.h>
#include <Wire.h>
#include <LiquidCrystal_I2C.h>

// Connect to the GPS on the hardware I2C port
Adafruit_GPS GPS(&Wire);
// set the LCD address to 0x27 for a 20 chars and 4 line display
LiquidCrystal_I2C lcd(0x27, 20, 4); // set the LCD address to 0x27 for a 20 chars and 4 line display

// 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 false

uint32_t timer = millis();


void setup()
{
  //while (!Serial);  // uncomment to have the sketch wait until Serial is ready

  // 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 I2C GPS library basic test!");
  //Initialize LCD
  lcd.init();
  lcd.init();
  lcd.backlight();

  // 9600 NMEA is the default baud rate for Adafruit MTK GPS's- some use 4800
  GPS.begin(0x10);  // The I2C address to use is 0x10
  // 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);

  delay(1000);

  // Ask for firmware version
  GPS.println(PMTK_Q_RELEASE);
}

void loop() // run over and over again
{
  // 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 trying 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
  }

  // approximately every 2 seconds or so, print out the current stats
  if (millis() - timer > 2000) {
    timer = millis(); // reset the timer
    Serial.print("\nTime: ");
    if (GPS.hour < 10) {
      Serial.print('0');
    }
    Serial.print(GPS.hour, DEC); Serial.print(':');
    if (GPS.minute < 10) {
      Serial.print('0');
    }
    Serial.print(GPS.minute, DEC); Serial.print(':');
    if (GPS.seconds < 10) {
      Serial.print('0');
    }
    Serial.print(GPS.seconds, DEC); Serial.print('.');
    if (GPS.milliseconds < 10) {
      Serial.print("00");
    } else if (GPS.milliseconds > 9 && GPS.milliseconds < 100) {
      Serial.print("0");
    }
    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("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);

      // LCD Data
      lcd.clear();
      lcd.backlight();
      lcd.setCursor(0, 0);
      lcd.print("LAT:");
      lcd.setCursor(5, 0);
      lcd.print(GPS.latitude, 4);
      lcd.print(GPS.lat);
      lcd.setCursor(0, 1);
      lcd.print("LON:");
      lcd.setCursor(5, 1);
      lcd.print(GPS.longitude, 4);
      lcd.print(GPS.lon);
      lcd.setCursor(0, 2);
      lcd.print("Altitude:");
      lcd.setCursor(9, 2); 
      lcd.print(GPS.altitude * 3.28084); 
      lcd.print(" Ft.");
      lcd.setCursor(0, 3);
      lcd.print("Satellites:");
      lcd.setCursor(12, 3); 
      lcd.print((int)GPS.satellites);

     }
  }
}

Tried setting the cursor line by line with my lcd code. I have no clue why this works verse my original lcd code but it makes sense. All of the set cursor weren't necessary but I wanted it to look better without any lose ends. I have run 4 lines on this lcd plenty of times and never ran into this.

Ron