#define echopin 9
#define trigpin 8
#define LED 7
#define gled 5 //green led
#define bled 2 //blue led
#define yled 3 //yellow led
#define cled 4 //cyan led
long duration;
int distance;



void setup() {
  // put your setup code here, to run once:
pinMode(trigpin, OUTPUT);
pinMode(echopin, INPUT);
Serial.begin(9600); // serial commu is starting with 9600 of baudrate speed
Serial.println("Ultrasonic Sensor HC-SR04 Test"); // print some text in serial number
Serial.println("with Arduino UNO R3");
}

void loop() {
digitalWrite(trigpin, LOW);
delayMicroseconds(2);

digitalWrite(trigpin, HIGH);
digitalWrite(LED, HIGH);
delayMicroseconds(10);
digitalWrite(trigpin, LOW);
digitalWrite(LED , LOW);

duration = pulseIn(echopin, HIGH);

distance = duration * 0.034 / 2;

Serial.print("Distance: ");
Serial.print(distance);
Serial.println("cm");


//gled
if(distance <=100){
  digitalWrite(gled, HIGH);
}
else{
  digitalWrite(gled, LOW);

}

//bled
if(distance <=200){
  digitalWrite(bled, HIGH);
}

else{
  digitalWrite(bled, LOW);

}

//yled
if(distance <=300){
  digitalWrite(yled, HIGH);
}

else{
  digitalWrite(yled, LOW);

}

//cled
if(distance <=394){
  digitalWrite(cled, HIGH);
}

else{
  digitalWrite(cled, LOW);

}

}