#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <Servo.h>

#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64

Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);

Servo myServo;

const int trigPin = 9;
const int echoPin = 10;

long duration;
int distance;

void setup() {
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  myServo.attach(6);

  Serial.begin(9600);

  // Inisialisasi OLED
  if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println("OLED gagal!");
    for(;;);
  }

  display.clearDisplay();
}

void loop() {
  // Kirim sinyal
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  // Baca jarak
  duration = pulseIn(echoPin, HIGH);
  distance = duration * 0.034 / 2;

  Serial.print("Jarak: ");
  Serial.println(distance);

  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(WHITE);

  display.setCursor(0, 0);
  display.print("Jarak: ");
  display.print(distance);
  display.println(" cm");

  if (distance < 20) {
    myServo.write(90);

    display.setCursor(0, 20);
    display.setTextSize(2);
    display.println("WARNING!");
  } else {
    myServo.write(0);

    display.setCursor(0, 20);
    display.setTextSize(2);
    display.println("AMAN");
  }

  display.display();
  delay(500);
}