#include <Servo.h>

#define trigPin 9       // Trig pin of HC-SR04
#define echoPin 10      // Echo pin of HC-SR04
#define relayPin 5      // Relay control pin (connected to Arduino)
#define servoPin 6      // Servo motor signal pin
#define eyeBlinkButton 7 // Eye blink button pin
#define buzzer 8        // Buzzer pin

Servo myServo; // Create Servo object

void setup() {
    pinMode(trigPin, OUTPUT);
    pinMode(echoPin, INPUT);
    pinMode(relayPin, OUTPUT);
    pinMode(eyeBlinkButton, INPUT_PULLUP); // Use internal pull-up resistor
    pinMode(buzzer, OUTPUT);
    
    myServo.attach(servoPin); // Attach servo to pin 6
    myServo.write(0); // Set servo to 0° initially
    digitalWrite(relayPin, LOW); // Ensure relay is off initially
    digitalWrite(buzzer, LOW); // Ensure buzzer is off initially

    Serial.begin(9600);
}

void loop() {
    detectObstacle();  // Function to handle obstacle detection
    checkEyeBlink();   // Function to handle eye blink detection
}

// Function to detect obstacle using ultrasonic sensor
void detectObstacle() {
    long duration;
    float distance;

    // Send ultrasonic pulse
    digitalWrite(trigPin, LOW);
    delayMicroseconds(2);
    digitalWrite(trigPin, HIGH);
    delayMicroseconds(10);
    digitalWrite(trigPin, LOW);

    // Receive echo
    duration = pulseIn(echoPin, HIGH);
    distance = (duration * 0.0343) / 2; // Convert time to distance in cm

    Serial.print("Distance: ");
    Serial.print(distance);
    Serial.println(" cm");

    if (distance <= 20 && distance > 0) { // If obstacle is within 20 cm
        digitalWrite(relayPin, HIGH); // Activate relay
        myServo.write(90); // Turn servo to 90°
        Serial.println("Obstacle detected! Servo rotated & Relay activated.");
    } else {
        digitalWrite(relayPin, LOW); // Deactivate relay
        myServo.write(0); // Reset servo to 0°
        Serial.println("Path Clear! Servo at 0° & Relay deactivated.");
    }

    delay(500); // Short delay to stabilize readings
}

// Function to check eye blink button press and activate buzzer
void checkEyeBlink() {
    if (digitalRead(eyeBlinkButton) == LOW) { // If button is pressed
        Serial.println("Buzzer ON");
        digitalWrite(buzzer, HIGH); // Turn on buzzer
        
        unsigned long buzzerStartTime = millis(); // Record start time
        while (millis() - buzzerStartTime < 4000) {
            // Keep buzzer on for 4 seconds without blocking other processes
        }

        digitalWrite(buzzer, LOW); // Turn off buzzer
        Serial.println("Buzzer OFF");

        // Wait for button release with debounce
        while (digitalRead(eyeBlinkButton) == LOW);
        delay(50); // Small debounce delay
    }
}