Automatic Lamp.c

#define F_CPU 16000000UL

#include <avr/io.h>
#include <avr/interrupt.h>
#include <util/delay.h>

// Define the pin numbers for the sensors and the relay
#define LDR_PIN PB3
#define MOTION_PIN PB1
#define RELAY_PIN PB2
#define BUTTON_PIN PB4

// Define constants for the ADC readings
#define LDR_THRESHOLD 500

void initADC(){
  	// Select ADC03  
  	ADMUX |= (1 << MUX0) | (1 << MUX1); 
    // Enable ADC with prescalar 128
    ADCSRA |= (1 << ADEN) | (1<< ADPS2) | (1<< ADPS1) |(1 << ADPS0);
}
// Function to read the analog value from the LDR sensor
uint16_t read_ldr() {
    // start conversion
    ADCSRA |= (1 << ADSC);  	
  	//wait for ADIF
    while (ADCSRA & (1 << ADSC));
    // Return the ADC result
    return ADC;
}

// Function to read the digital value from the MOTION sensor
uint8_t read_motion() {
    // Read the digital value from the MOTION pin
    return PINB & (1 << MOTION_PIN);
}

uint8_t relay_state = 0; // Initially off

void initInterrupt() {
    // Set BUTTON_PIN as input
    DDRB &= ~(1 << BUTTON_PIN);  
    // Enable external interrupt on BUTTON_PIN
    PCMSK |= (1 << PCINT4); // Enable interrupt for BUTTON_PIN
    GIMSK |= (1 << PCIE); // Enable pin change interrupt for PCINT7..0
   
}

ISR(PCINT0_vect) {
    // Debounce the button
    _delay_ms(200);
    // Check if the button is pressed
    if (PINB & (1 << BUTTON_PIN)) {
        // Toggle the relay state
        relay_state = !relay_state;       
        if (relay_state) {
            PORTB |= (1 << RELAY_PIN); // Turn on the relay
        } else {
            PORTB &= ~(1 << RELAY_PIN); // Turn off the relay
        }
    }
}

int main(void) {
    // Initialize the ADC
    initADC();
    // Configure the pin directions
    DDRB |= (1 << RELAY_PIN); // Relay pin as output
    // Initialize the relay state
    relay_state = 0; // Initially off   
    // Set PB2 as an input pin
    DDRB &= ~(1 << MOTION_PIN);
    // Enable the internal pull-up resistor for PB5
    PORTB |= (1 << MOTION_PIN);
    // Enable global interrupts
    sei();
    initInterrupt();
    while (1) {
        // Read the sensor values
        uint16_t ldr_value = read_ldr();
        uint8_t motion_value = read_motion();
        // Check the LDR value and the MOTION value
        if (ldr_value > LDR_THRESHOLD && motion_value) {
		relay_state = 1;
            // Turn on the relay for 2 minutes
            PORTB |= (1 << RELAY_PIN);
            _delay_ms(120000);
            PORTB &= ~(1 << RELAY_PIN);
			relay_state = 0;
        } 
        _delay_ms(1000);
    }
    
}