gistfile1.cpp

#include <SoftwareSerial.h>
#include <helium.h>

HeliumModem *modem;

void setup() {
  modem = new HeliumModem();
}

void loop() {
  static u32 lastTime;
  u32 time;
  
  time = millis();
  if (time - lastTime > 5000) {
    lastTime = time;
    DataPack dp(1);
    dp.appendFloat((float)get_temp());
    modem->sendPack(&dp);
  }
}

// return onboard temperature in degrees celcius
double get_temp(void) {
  unsigned int wADC;
  double t;

  // set the internal reference and mux
  ADMUX = (_BV(REFS1) | _BV(REFS0) | _BV(MUX3));
  ADCSRA |= _BV(ADEN); // enable the ADC

  delay(20); // wait for voltages to become stable

  ADCSRA |= _BV(ADSC); // start the ADC

  // detect end-of-conversion
  while (bit_is_set(ADCSRA, ADSC));

  // reading register "adcw" takes care of how to read adcl and adch
  wADC = ADCW;

  t = (wADC - 324.31) / 1.22;
  
  // convert to F
  t = ((t * 9) / 5) + 32;
  return t;
}