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

#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64

#define OLED_RESET     -1
#define SCREEN_ADDRESS 0x3C
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

const int trigPin = 25;  // TRIG pin
const int echoPin = 33; // ECHO pin

// Define sound speed in cm/usec
const float SOUND_SPEED = 0.034;

void setup() {
  Serial.begin(115200);
  
  // Initialize OLED display
  if(!display.begin(SSD1306_SWITCHCAPVCC, SCREEN_ADDRESS)) {
    Serial.println(F("Gagal Terkoneksi"));
    for(;;);
  }
  display.clearDisplay();
  display.setTextSize(2);
  display.setTextColor(SSD1306_WHITE);
  
  // Initialize ultrasonic sensor pins
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
}

float measureDistance() {
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  
  long duration = pulseIn(echoPin, HIGH);
  float distanceCm = duration * SOUND_SPEED / 2;
  
  return distanceCm;
}

void loop() {
  float distance = measureDistance();
  
  display.clearDisplay();
  display.setCursor(0, 0);
  display.print("Distance:");
  display.setCursor(0, 30);
  display.print(distance, 1);
  display.print(" cm");
  display.display();
  
  Serial.print("Distance (cm): ");
  Serial.println(distance);
  
  delay(500);
}