#include <LiquidCrystal_I2C.h>


LiquidCrystal_I2C lcd(0x27, 16, 2);

long bacaJarak (int triggerPin, int echoPin){
pinMode(triggerPin, OUTPUT);
digitalWrite(triggerPin, LOW);
digitalWrite(triggerPin, HIGH);
delayMicroseconds(19);
digitalWrite(triggerPin, LOW);
pinMode(echoPin, INPUT);
return pulseIn(echoPin, HIGH);
}

// deklarasi pin
int red = 10;
int yellow = 11;
int green = 12;

void setup() {
Serial.begin(9600);
// inisialisasi lcd
lcd.init();
lcd.backlight();
//inisialisasi led
pinMode(red, OUTPUT);
pinMode(yellow, OUTPUT);

pinMode(green, OUTPUT);
}

void loop() {
//pembacaan ultrasonik
int cm = 0;
cm = (0.03446 * bacaJarak(7, 8))/2;
int mm = cm*100;
// menampilkan pembacaan sensor ke monitor
Serial.print(cm);
Serial.println("cm");
delay(100);
// percabangan kondisi led sesuai pembacaan sensor
if (cm > 0 && cm<10){
lcd.setCursor(0,0);
lcd.print("Hijau menyala.");
digitalWrite(green, 1);
delay(100);
lcd.clear();
} else if (cm>11 && cm <20){
lcd.setCursor(0,0);
lcd.print("Kuning menyala.");
digitalWrite(yellow, 1);
delay(100);
lcd.clear();

} else if (cm>21 && cm<30){
lcd.setCursor(0,0);
lcd.print("Merah nyala.");
digitalWrite(red, 1);
delay(100);
lcd.clear();
} else if ( cm > 31) {
lcd.setCursor(0,0);
lcd.print("Lampu berkedip.");
digitalWrite(red, 1);
digitalWrite(yellow, 1);
digitalWrite(green, 1);
delay(1000);
digitalWrite(red, 0);
digitalWrite(yellow, 0);
digitalWrite(green, 0);
lcd.clear();
}
}