Arduino Temperature Light

.cc

#include <OneWire.h>

int Temp_Pin = 2;
int outputPins[] = {10, 11, 12};

OneWire ds(Temp_Pin);

void setup() {
  Serial.begin(9600);
  for (int i = 0; i < 3; i++) {
    pinMode(outputPins[i], OUTPUT);  
  }
}

void loop() {
  float temperature = getTemp();
  Serial.println(temperature);

  if (temperature < 20) {
    lightOn(0);
  } else if (temperature >= 20 && temperature < 25) {
    lightOn(1); 
  } else {
    lightOn(2);
  }

  delay(100);
}

float getTemp(){
  //returns the temperature from one DS18S20 in DEG Celsius

  byte data[12];
  byte addr[8];

  // Search for next device
  if ( !ds.search(addr)) {
      //no more sensors on chain, reset search
      ds.reset_search();
      return -1000;
  }

  Serial.print("R=");
  for( i = 0; i < 8; i++) {
    Serial.print(addr[i], HEX);
    Serial.print(" ");
  }

  // Data integrity verification
  if ( OneWire::crc8( addr, 7) != addr[7]) {
      Serial.println("CRC is not valid!");
      return -1000;
  }

  if ( addr[0] != 0x10 && addr[0] != 0x28) {
      Serial.print("Device is not recognized");
      return -1000;
  }

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

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

  
  for (int i = 0; i < 9; i++) { // we need 9 bytes
    data[i] = ds.read();
  }
  
  ds.reset_search();
  
  byte MSB = data[1];
  byte LSB = data[0];

  float tempRead = ((MSB << 8) | LSB); //using two's compliment
  float TemperatureSum = tempRead / 16;
  
  return TemperatureSum;
  
}

void lightOn(int index) {
  for (int i = 0; i < 3; i++) {
    if (i == index) {
      digitalWrite(outputPins[i], HIGH);
    } else {
      digitalWrite(outputPins[i], LOW);
    }
  }
}