HC-SR04

/*
Contoh program sensor HC-SR04
created by papermindvention.blogspot.com
march 2018
*/
const int trigPin = 2;
const int echoPin = 3;
int led= 13;
int duration = 0; //variable untuk menyimpan hasil inputan echo
int jarak = 0; //variable untuk menyimpan hasil dari perhitungan jarak
void setup(){
Serial.begin(9600);
pinMode(trigPin, OUTPUT);
pinMode(echoPin, INPUT);
pinMode(led, OUTPUT);}
void loop() {
digitalWrite(trigPin, LOW);
delayMicroseconds(2);
digitalWrite(trigPin, HIGH);
delayMicroseconds(10);
digitalWrite(trigPin, LOW);
duration = pulseIn(echoPin, HIGH);
jarak = (duration*0.034)/2;//rumus
Serial.print(jarak);
Serial.println(" cm");
Serial.println(duration);

if (jarak<=70) {
  digitalWrite(led, HIGH);}
else {  digitalWrite(led, LOW);  }
}