#define pinTrig 3
#define pinEcho 2
#define pinBuz 13

long waktu, jarak;

void setup() {
Serial.begin(9600);
pinMode (pinBuz, OUTPUT);
pinMode (pinTrig, OUTPUT);
pinMode (pinEcho, INPUT);
}

void loop() {
digitalWrite (pinTrig, LOW);
delayMicroseconds (2);
digitalWrite (pinTrig, HIGH);
delayMicroseconds (10);
digitalWrite(pinTrig, LOW);

waktu = pulseIn(pinEcho, HIGH);
jarak = waktu / 58.2;

if (jarak < 250 && jarak >= 200) {
 tone (pinBuz, 100);
 delay (50);
 noTone(pinBuz);
}
}