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

// OLED display settings
#define SCREEN_WIDTH 128  // OLED width in pixels
#define SCREEN_HEIGHT 64  // OLED height in pixels
#define OLED_RESET    -1  // Reset pin (not used)

// Initialize the OLED display
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

// Define ultrasonic sensor pins
const int trigPin = 2;
const int echoPin = 3;

// Variables for ultrasonic sensor
long duration;
int distance;

void setup() {
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  
  Serial.begin(9600);  // Initialize serial monitor

  // Initialize OLED display
  if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) { 
    Serial.println("SSD1306 initialization failed!");
    while (1);  // Halt execution if display initialization fails
  }

  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(WHITE);
  display.setCursor(10, 10);
  display.println("Ultrasonic Sensor");
  display.display();
  delay(2000);  // Show welcome message for 2 seconds
}

void loop() {
  // Send a short pulse to trigger pin
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  // Read echo pulse duration
  duration = pulseIn(echoPin, HIGH);
  
  // Convert duration to distance in millimeters
  distance = duration * 0.034 / 2 * 10;

  // Print to Serial Monitor
  Serial.print("Distance: ");
  Serial.print(distance);
  Serial.println(" mm");

  // Display distance on OLED
  display.clearDisplay();
  display.setTextSize(1.75);
  display.setTextColor(WHITE);
  display.setCursor(10, 20);
  display.print("Dist: ");
  display.print(distance);
  display.println(" mm");
  display.display();  // Update OLED display

  delay(500);  // Delay before the next reading
}