int r= 4 ;
int y= 3 ;
int g= 2 ;
int sensor;
int sensor_pin=A1 ;


void setup() {
pinMode(r, OUTPUT);
pinMode(y, OUTPUT);
pinMode(g, OUTPUT);
pinMode(sensor_pin, INPUT);
Serial.begin(9600);










}

void loop() {
 sensor= analogRead(sensor_pin);
Serial.println(sensor);
delay(100);
if((sensor>100)&&(sensor<400)){
digitalWrite(r, HIGH);
digitalWrite(y, LOW);
digitalWrite(g, LOW);

}

if((sensor>400)&&(sensor<800)){
digitalWrite(r, LOW);
digitalWrite(y, HIGH);
digitalWrite(g, LOW);

}
if(sensor>=800){
digitalWrite(r, LOW);
digitalWrite(y, LOW);
digitalWrite(g, HIGH);

}else{
digitalWrite(r, LOW);
digitalWrite(y, LOW);
digitalWrite(g, LOW);





}
}