#include <TM1637Display.h>

// Pin definitions
const int trigPin = 9;
const int echoPin = 10;
const int relayPin = 8;
const int buttonPin = 7;
const int buzzerPin = 6;

// 4-Digit Display (TM1637)
#define CLK 2
#define DIO 3
TM1637Display display(CLK, DIO);

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

// State variables
bool relayState = false;
bool buttonPressed = false;

void setup() {
  // Initialize serial communication
  Serial.begin(9600);

  // Pin modes
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  pinMode(relayPin, OUTPUT);
  pinMode(buttonPin, INPUT_PULLUP);
  pinMode(buzzerPin, OUTPUT);

  // Turn off relay and buzzer at the start
  digitalWrite(relayPin, LOW);
  digitalWrite(buzzerPin, LOW);

  // Initialize display
  display.setBrightness(0x0f); // Set brightness
  display.showNumberDec(0);    // Initialize display with 0
}

void loop() {
  // Measure distance using HC-SR04
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  
  duration = pulseIn(echoPin, HIGH);
  distance = duration * 0.034 / 2;  // Calculate distance in cm

  // Show the distance on the 4-digit display
  display.showNumberDec(distance);

  // Check if push button is pressed
  if (digitalRead(buttonPin) == LOW && !buttonPressed) {
    buttonPressed = true;  // Set flag
    relayState = !relayState;  // Toggle relay state
    delay(200);  // Debounce delay
  }

  // Reset button flag after release
  if (digitalRead(buttonPin) == HIGH && buttonPressed) {
    buttonPressed = false;
  }

  // Control the relay
  if (relayState) {
    digitalWrite(relayPin, HIGH);  // Turn relay on
    digitalWrite(buzzerPin, HIGH); // Turn buzzer on
  } else {
    digitalWrite(relayPin, LOW);   // Turn relay off
    digitalWrite(buzzerPin, LOW);  // Turn buzzer off
  }

  // Small delay before repeating loop
  delay(100);
}