const int hallPin = 4;   // Hall sensor connected to D2
const int ledPin1 = 2;
const int ledPin2 = 1;
const int ledPin3 = 0;
const int ledPin4 = 3;
   // Built-in LED pin
bool ledState = false;   // Keep track of LED state
bool lastHallState = HIGH; // Previous reading from Hall sensor

void setup() {
  //Serial.begin(9600);                     // Start serial communication
  pinMode(hallPin, INPUT_PULLUP);        // Use internal pull-up for Hall sensor
  pinMode(ledPin1, OUTPUT);               // Set LED pin as output
  digitalWrite(ledPin1, LOW);  
   pinMode(ledPin2, OUTPUT);               // Set LED pin as output
  digitalWrite(ledPin2, LOW);  
   pinMode(ledPin3, OUTPUT);               // Set LED pin as output
  digitalWrite(ledPin3, LOW); 
   pinMode(ledPin4, OUTPUT);               // Set LED pin as output
  digitalWrite(ledPin4, LOW);          // Start with LED off
  //Serial.println("Ready! Bring magnet close to toggle LED.");
}

void loop() {
  int hallStatus = digitalRead(hallPin);  // Read Hall sensor

  // Detect falling edge: HIGH → LOW (magnet just got close)
  if (lastHallState == HIGH && hallStatus == LOW) {
    ledState = !ledState;                         // Toggle the LED state
    digitalWrite(ledPin1, ledState ? HIGH : LOW); 
     digitalWrite(ledPin2, ledState ? HIGH : LOW);
      digitalWrite(ledPin3, ledState ? HIGH : LOW);
       digitalWrite(ledPin4, ledState ? HIGH : LOW); // Update the LED
   // Serial.print("Magnet Detected! LED ");
    //Serial.println(ledState ? "ON" : "OFF");
  }

  lastHallState = hallStatus;  // Update the previous Hall sensor state
  delay(50);                   // Debounce delay
}