#define red 5
#define green 0
#define btn 3
#define rel 1
#define sensor A1

void setup() 
{    
    pinMode(red,OUTPUT);
    pinMode(green,OUTPUT);
    pinMode(rel,OUTPUT);
    pinMode(btn,INPUT_PULLUP);
    pinMode(sensor,INPUT);
}

void loop() 
{
    if(analogRead(sensor)<500)
    {
      digitalWrite(red, LOW);
      digitalWrite(rel, LOW);
      digitalWrite(green, HIGH);
    }
    else
    {
      digitalWrite(red, HIGH);
      digitalWrite(rel, HIGH);
      digitalWrite(green, LOW);
    }  
   
    delay(555);
}