Untitled

// Define the pin number for the Temp Sensor and LEDs
const int TempPin = A0;
const int GreenPin = 4;
const int YellowPin = 3;
const int RedPin = 2;

// Reset the state of the Temp Sensor

volatile int Temp = 0; // Initialize to 0

// Interrupt Service Routine (ISR) for the Temp Sensor pin
ISR(TIMER1_COMPA_vect)
{
  // Read the current state of the button
float Temp = analogRead(TempPin);
 //analog to digital.
float Volts=(Temp*5)/1024;
  //conversion that fits the simulation.(we got values *2 higher than expected)
  float cel=Volts*100;
  
  Serial.print("temp = ");
  Serial.println(cel);
  //change the led according to the temp
  if(cel<30) 
  {
    // turn on the green LED
    digitalWrite(GreenPin, HIGH);
    digitalWrite(YellowPin, LOW);
    digitalWrite(RedPin, LOW);
  }
  //change the led according to the temp
  if (cel>40&&cel<70) 
  {
    // turn on the yellow LED
    digitalWrite(GreenPin, LOW);
    digitalWrite(YellowPin, HIGH);
    digitalWrite(RedPin, LOW);
  }
  //change the led according to the temp
  if (cel>70) 
  {
    // turn on the red LED
    digitalWrite(GreenPin, LOW);
    digitalWrite(YellowPin, LOW);
    digitalWrite(RedPin, HIGH);
  }
}

void setup() 
{
  // Set the Temp Sensor pin as an input
  pinMode(TempPin, INPUT);
  // Set the LEDs pins as an Output
  pinMode(GreenPin, OUTPUT);
  pinMode(YellowPin, OUTPUT);
  pinMode(RedPin, OUTPUT);
//int sec;
  
  
  // initialize timer1 
  noInterrupts();           // disable all interrupts
  timer1_init(1000);//period time in msec
  interrupts();             // enable all interrupts
  // Start communication with the serial monitor at a baud rate of 9600
  Serial.begin(9600);
}

void loop() {
  // Loop from 0 to 99 and print each number to the serial monitor
/*  for (int i = 0; i < 100; i++) {
    Serial.println(i);
	}*/
}

void timer1_init(int msec) {
  // initialize timer1 to freq=16M/(2*256)=31250Hz
  //1 sec interrupt--> OCR1A = 31250/2 cycles=15625 cycles=1/2 sec
  TCCR1A = 0;// set entire TCCR1A register to 0
  TCCR1B = 0;// same for TCCR1B
  TCNT1 = 0;//initialize counter value to 0
  // set compare match register for 1hz increments
  //OCR1A = 15624;// = (1610^6) / (11024) - 1 (must be <65536)
  OCR1A = (int)15.624*msec;
  // turn on CTC mode
  TCCR1B |= (1 << WGM12);
  // Set CS10 and CS12 bits for 1024 prescaler
  TCCR1B |= (1 << CS12) | (1 << CS10);
  // enable timer compare interrupt
  TIMSK1 |= (1 << OCIE1A);
}