As part of an undergraduate geography project, I am attempting to combine the Ultimate GPS logging shield with the DHT22 Temperature/RH sensor. I have the hardware all set and working and most of the software, but for the life of me I cannot understand how to write the temperature and RH values to the end (or at all) with the GPS coordinates. What I ultimately need is a "NMEA sentence, temperature reading, relative humidity reading" all on one line and comma separated for further processing in ArcGIS and R.
Any help as to where I am going wrong would be greatly appreciated. I have posted the sketch as I have cobbled it together below (sensor data coming in on pin 2).
Thank you,
Jeffrey Ashby
IUPUI Geography Department Senior
-- Begin sketch --
Code: Select all
#include <SPI.h>
#include <Adafruit_GPS.h>
#include <SoftwareSerial.h>
#include <SD.h>
#include <avr/sleep.h>
#include "DHT.h"
// Ladyada's logger modified by Bill Greiman to use the SdFat library
//
// This code shows how to listen to the GPS module in an interrupt
// which allows the program to have more 'freedom' - just parse
// when a new NMEA sentence is available! Then access data when
// desired.
//
// Tested and works great with the Adafruit Ultimate GPS Shield
// using MTK33x9 chipset
// ------> http://www.adafruit.com/products/
// Pick one up today at the Adafruit electronics shop
// and help support open source hardware & software! -ada
SoftwareSerial mySerial(8, 7);
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 false
/* set to true to only log to SD when GPS has a fix, for debugging, keep it false */
#define LOG_FIXONLY true
// Set the pins used
#define chipSelect 10
#define ledPin 13
#define DHTPIN 2 // what pin we're connected to
#define DHTTYPE DHT22 // DHT 22 (AM2302)
#define data
DHT dht(DHTPIN, DHTTYPE);
File logfile;
// read a Hex value and return the decimal equivalent
uint8_t parseHex(char c) {
if (c < '0')
return 0;
if (c <= '9')
return c - '0';
if (c < 'A')
return 0;
if (c <= 'F')
return (c - 'A')+10;
}
// blink out an error code
void error(uint8_t errno) {
/*
if (SD.errorCode()) {
putstring("SD error: ");
Serial.print(card.errorCode(), HEX);
Serial.print(',');
Serial.println(card.errorData(), HEX);
}
*/
while(1) {
uint8_t i;
for (i=0; i<errno; i++) {
digitalWrite(ledPin, HIGH);
delay(100);
digitalWrite(ledPin, LOW);
delay(100);
}
for (i=errno; i<10; i++) {
delay(200);
}
}
}
void setup() {
// for Leonardos, if you want to debug SD issues, uncomment this line
// to see serial output
//while (!Serial);
// 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("\r\nUltimate GPSlogger Shield");
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!");
error(2);
}
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);
error(3);
}
Serial.print("Writing to "); Serial.println(filename);
// connect to the GPS at the desired rate
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 logging data, we don't suggest using anything but either RMC only or RMC+GGA
// to keep the log files at a reasonable size
// Set the update rate
GPS.sendCommand(PMTK_SET_NMEA_UPDATE_1HZ); // 1 or 5 Hz update rate
// Turn off updates on antenna status, if the firmware permits it
GPS.sendCommand(PGCMD_NOANTENNA);
Serial.println("Ready!");
dht.begin();
}
void loop() {
float h = dht.readHumidity();
float t = dht.readTemperature();
char c = GPS.read();
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
// Sentence parsed!
Serial.println("OK");
if (LOG_FIXONLY && !GPS.fix) {
Serial.print("No Fix");
return;
}
// Rad. lets log it!
Serial.println("Log");
char *stringptr = GPS.lastNMEA();
uint8_t stringsize = strlen(stringptr);
if (stringsize != logfile.write((uint8_t *)stringptr, stringsize)) //write the string to the SD file
error(4);
if (strstr(stringptr, "RMC")) logfile.flush();
Serial.println();
}
}
/* End code */