int led1=12;
int led2=11;
int led3=10;
int led4=9;
int trig=8;
int echo=7;
int waktu=0;
int jarak=0;
int bz=6;
void setup() {
pinMode(led1, OUTPUT);
pinMode(led2, OUTPUT);
pinMode(led3, OUTPUT);
pinMode(led4, OUTPUT);
pinMode(trig, OUTPUT);
pinMode(echo,INPUT);
pinMode(bz, OUTPUT);
Serial.begin(9600);
}

void loop() {
digitalWrite(trig, HIGH);
delayMicroseconds(1000);
digitalWrite(trig, LOW);

waktu=pulseIn(echo, HIGH);
jarak=(waktu/2) / 29.1;
Serial.print("jarak:");
Serial.print(jarak);
Serial.println("CM");
if (jarak<50){
digitalWrite(led1,1);
digitalWrite(led2,1);
digitalWrite(led3,1);
digitalWrite(led4,1);
delay(500);
buzzer1();
}
else if (jarak<100){
digitalWrite(led1,0);
digitalWrite(led2,0);
digitalWrite(led3,0);
digitalWrite(led4,1);
delay(500);
buzzer();
}
else if (jarak<200){
digitalWrite(led1,0);
digitalWrite(led2,0);
digitalWrite(led3,1);
digitalWrite(led4,0);
delay(500);
buzzer();
}
else if (jarak<300){
digitalWrite(led1,0);
digitalWrite(led2,1);
digitalWrite(led3,0);
digitalWrite(led4,0);
delay(500);
buzzer();
}
else if (jarak<=400){
digitalWrite(led1,1);
digitalWrite(led2,0);
digitalWrite(led3,0);
digitalWrite(led4,0);
delay(500);
buzzer();
}
}
void buzzer(){
tone( bz,1000);
delay(500);
noTone(bz);
}
void buzzer1(){
tone(bz,1000);
delay(50);
noTone(bz);
}