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

#define ECHO_PIN 12
#define TRIG_PIN 13

#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64

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

void setup() {
  if (!oled.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println(F("SSD1306 allocation failed"));
    for (;;);
  }

  delay(2000);

  oled.clearDisplay();
  oled.setTextSize(1);
  oled.setTextColor(WHITE);
  oled.setCursor(0, 0);
  oled.println("Ultrasonic Sensor");

  pinMode(ECHO_PIN, INPUT);
  pinMode(TRIG_PIN, OUTPUT);
}

void loop() {
  long duration;
  float distance;

  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);
  duration = pulseIn(ECHO_PIN, HIGH);

  distance = duration * 0.034 / 2;

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

  delay(1000);
}