Temperature module - cjus/hydra-cluster GitHub Wiki

#include <OneWire.h>
#include <Wire.h>
#include <LiquidCrystal.h>

#define LCD_WIDTH 16
#define LCD_HEIGHT 2

OneWire ds(11);  // on pin 11
LiquidCrystal lcd(12, 2, 4, 5, 6, 7);

void setup() {
  Serial.begin(9600);
  lcd.begin(LCD_WIDTH, LCD_HEIGHT);
  lcd.clear();
  lcd.setCursor(1, 0);
  lcd.print("HYDRA  CLUSTER");
}

void loop() {
  displayUptime();
  displayTemperature();
  delay(1000);
}

void displayUptime() {
  char buf[LCD_WIDTH];
  unsigned int days = 0;
  unsigned int hours = 0;
  unsigned int mins = 0;
  unsigned int secs = 0;

  secs = millis() / 1000;

  mins = secs / 60;
  hours = mins / 60;
  days = hours / 24;

  secs = secs - (mins * 60);
  mins = mins - (hours * 60);
  hours = hours - (days * 24);

  sprintf(buf, "%02d %02d:%02d:%02d", days, hours, mins, secs);
  lcd.setCursor(0, 1);
  lcd.print(buf);
  Serial.write(buf);
  Serial.write('|');
}

void displayTemperature() {
  int HighByte, LowByte, TReading, SignBit, Tc_100, Tf_100, Whole, Fract;
  char buf[LCD_WIDTH];

  byte i, sensor;
  byte present = 0;
  byte data[12];
  byte addr[8];

  ds.reset_search();
  if (!ds.search(addr)) {
    lcd.setCursor(0,0);
    lcd.print("No more addr.");
    ds.reset_search();
    delay(250);
    return;
  }

  if (OneWire::crc8(addr, 7) != addr[7]) {
    lcd.setCursor(0,0);
    lcd.print("CRC not valid");
    return;
  }

  if (addr[0] != 0x28) {
    lcd.setCursor(0,0);
    lcd.print("Not a DS18B20.");
    return;
  }

  ds.reset();
  ds.select(addr);
  ds.write(0x44, 1);         // start conversion, with parasite power on at the end

//  delay(2000);     // maybe 750ms is enough, maybe not
  // we might do a ds.depower() here, but the reset will take care of it.

  present = ds.reset();
  ds.select(addr);
  ds.write(0xBE);         // Read Scratchpad

  for (i = 0; i < 9; i++) {
    data[i] = ds.read();
  }

  LowByte = data[0];
  HighByte = data[1];
  TReading = (HighByte << 8) + LowByte;
  SignBit = TReading & 0x8000;  // test most sig bit
  if (SignBit) { // negative
    TReading = (TReading ^ 0xffff) + 1; // 2's comp
  }
  Tc_100 = (6 * TReading) + TReading / 4;    // multiply by (100 * 0.0625) or 6.25
  Tf_100 = ((Tc_100 * 9.0) / 5.0  + 32 * 100) / 100;
  //TODO: use this instead: fahrenheit = (cel * 1.8) + 32;

  //sprintf(buf, "%d\337", Tf_100);
  sprintf(buf, "%dF", Tf_100);
  int pos = LCD_WIDTH - strlen(buf);
  lcd.setCursor(pos, 1);
  lcd.print(buf);
  Serial.write(buf);
  Serial.write('\n');
}