#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#define TRIG_PIN 9
#define ECHO_PIN 10
#define LED_PIN 7
#define BUZZER_PIN 8
LiquidCrystal_I2C lcd(0x27, 16, 2);
void setup() {
pinMode(TRIG_PIN, OUTPUT);
pinMode(ECHO_PIN, INPUT);
pinMode(LED_PIN, OUTPUT);
pinMode(BUZZER_PIN, OUTPUT);
Wire.begin();
lcd.init();
lcd.backlight();
lcd.clear();
lcd.setCursor(0, 0);
lcd.print("Sistem Siap...");
delay(1500);
lcd.clear();
}
long bacaJarak() {
digitalWrite(TRIG_PIN, LOW);
delayMicroseconds(2);
digitalWrite(TRIG_PIN, HIGH);
delayMicroseconds(10);
digitalWrite(TRIG_PIN, LOW);
long durasi = pulseIn(ECHO_PIN, HIGH, 30000);
if (durasi == 0) return 999;
return durasi * 0.034 / 2;
}
void loop() {
long jarak = bacaJarak();
if (jarak < 100) {
// LED ON
digitalWrite(LED_PIN, HIGH);
// LCD: nada dihidupkan
lcd.clear();
lcd.setCursor(0, 0);
lcd.print("nada dihidupkan");
lcd.setCursor(0, 1);
lcd.print("Jarak:");
lcd.print(jarak);
lcd.print("cm");
// Buzzer nada 400 Hz, delay 500ms
tone(BUZZER_PIN, 400);
delay(500);
noTone(BUZZER_PIN);
// Buzzer nada 500 Hz, delay 500ms
tone(BUZZER_PIN, 500);
delay(500);
noTone(BUZZER_PIN);
} else {
// LED OFF
digitalWrite(LED_PIN, LOW);
noTone(BUZZER_PIN);
// LCD: nada 500 (mati)
lcd.clear();
lcd.setCursor(0, 0);
lcd.print("nada 500");
lcd.setCursor(0, 1);
lcd.print("Jarak:");
lcd.print(jarak);
lcd.print("cm");
delay(300);
}
}