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

// OLED display dimensions
#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64

// Ultrasonic sensor pins
#define TRIG_PIN 9
#define ECHO_PIN 10

// Initialize the OLED display
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire,-1);

// Variable to store the previous distance
long previousDistance = 0;

void setup() {
 
  Serial.begin(9600);


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

  // Initialize the OLED display
  if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {  // Check I2C address (usually 0x3C)
    Serial.println(F("SSD1306 allocation failed"));
    for (;;);  // Infinite loop if OLED initialization fails
  }

  
  display.display();  
  delay(2000);       
  display.clearDisplay();  
}

void loop() {
  long duration, 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;
  
  String changeStatus;
  if (distance > previousDistance) {
    changeStatus = "Increased";
  } else if (distance < previousDistance) {
    changeStatus = "Decreased";
  } else {
    changeStatus = "No Change";
  }

  
  display.clearDisplay(); 
  display.setTextSize(1);  
  display.setTextColor(SSD1306_WHITE); 
  display.setCursor(0, 0); 
  display.print("Distance: ");
  display.print(distance);
  display.println(" cm");

 
  display.setCursor(0, 20);  
  display.print("Status: ");
  display.println(changeStatus);

 
  display.display();  

 
  previousDistance = distance;
  delay(1000);
}