Contactless IoT Doorbell Security System with Raspberry Pi & Camera

Educational Notes

This project is designed to be accessible to students from Class 4 to Masters level, with complexity scalable to match different age groups and skill levels.

Learning Objectives:

• Understand basic electronics and circuitry principles
• Learn sensor applications and data collection techniques
• Develop problem-solving skills through hands-on building and troubleshooting
• Apply programming concepts to control hardware and process data
• Connect projects to real-world Nepalese contexts and challenges

Adaptability:

• For younger students (Class 4-8): Focus on assembling pre-built circuits, observing results, and understanding basic concepts
• For intermediate students (Class 9-12): Modify code, experiment with parameters, and explore underlying principles
• For advanced students (Undergraduate/Masters): Optimize designs, add features, conduct research extensions, and analyze performance

Safety Note: Always supervise younger students when working with electricity, heat, or moving parts.

Enhance home security with a contactless IoT doorbell that captures visitor photos, performs facial recognition, and sends instant alerts to your smartphone via Telegram or WhatsApp.

Hardware Bill of Materials (In Stock at Ghumti Pasal):

• Controller: Raspberry Pi 4 Model B 4GB / 8GB
• Camera: Raspberry Pi Camera Module V2 / HQ Camera
• Motion Sensor: HC-SR501 PIR Motion Sensor Module
• Button: Tactile Push Button 12x12mm
• Audio: Active Buzzer + Small Speaker
• Power: 5V 3A USB-C Power Adapter
• Storage: MicroSD Card 32GB Class 10

Circuit Pinout & Wiring Connections:

Firmware Source Code (Python 3)

import cv2
import face_recognition
import requests
import RPi.GPIO as GPIO
import time
from datetime import datetime
from picamera2 import Picamera2

# Telegram Bot Configuration
BOT_TOKEN = "YOUR_BOT_TOKEN"
CHAT_ID = "YOUR_CHAT_ID"

# GPIO Setup
GPIO.setmode(GPIO.BCM)
GPIO.setup(17, GPIO.IN)  # PIR Sensor
GPIO.setup(27, GPIO.IN, pull_up_down=GPIO.PUD_UP)  # Doorbell Button
GPIO.setup(22, GPIO.OUT)  # Buzzer

# Camera Setup
picam2 = Picamera2()
config = picam2.create_still_configuration(main={"size": (1920, 1080)})
picam2.configure(config)
picam2.start()

known_face_encodings = []
known_face_names = []

def send_telegram_alert(image_path, message):
    url = f"https://api.telegram.org/bot{BOT_TOKEN}/sendPhoto"
    with open(image_path, 'rb') as photo:
        files = {'photo': photo}
        data = {'chat_id': CHAT_ID, 'caption': message}
        requests.post(url, files=files, data=data)

def capture_and_process():
    timestamp = datetime.now().strftime("%Y%m%d_%H%M%S")
    image_path = f"/home/pi/doorbell_{timestamp}.jpg"
    picam2.capture_file(image_path)
    
    # Face recognition
    image = face_recognition.load_image_file(image_path)
    face_locations = face_recognition.face_locations(image)
    face_encodings = face_recognition.face_encodings(image, face_locations)
    
    recognized_names = []
    for face_encoding in face_encodings:
        matches = face_recognition.compare_faces(known_face_encodings, face_encoding)
        name = "Unknown Visitor"
        if True in matches:
            first_match_index = matches.index(True)
            name = known_face_names[first_match_index]
        recognized_names.append(name)
    
    message = f"🚪 Doorbell Alert! {datetime.now().strftime('%H:%M:%S')}\n"
    if recognized_names:
        message += f"Recognized: {', '.join(recognized_names)}"
    else:
        message += "No known faces detected"
    
    send_telegram_alert(image_path, message)
    
    # Local chime
    for _ in range(3):
        GPIO.output(22, True)
        time.sleep(0.1)
        GPIO.output(22, False)
        time.sleep(0.1)

try:
    print("Contactless Doorbell System Active...")
    while True:
        # Check PIR motion
        if GPIO.input(17):
            print("Motion detected - capturing...")
            capture_and_process()
            time.sleep(5)  # Debounce
        
        # Check doorbell button
        if not GPIO.input(27):
            print("Button pressed - capturing...")
            capture_and_process()
            time.sleep(2)
            
        time.sleep(0.1)

except KeyboardInterrupt:
    GPIO.cleanup()

Cloud Integration & Mobile App

• Telegram Bot: Instant photo alerts with visitor identification
• WhatsApp Integration: Use Twilio WhatsApp API for broader reach
• Local Storage: Photos saved on Pi with timestamped filenames
• Web Dashboard: Optional Flask web interface for live view

Nepal-Specific Applications

• Kathmandu Apartments: Contactless entry for multi-family buildings
• Remote Villages: Solar-powered doorbell with LoRa mesh network
• Elderly Care: Family notifications when caregivers visit
• Small Businesses: Shop visitor analytics and security logging

Troubleshooting Guide

Cost Breakdown (NPR)

Future Enhancements

• Add RFID/NFC tag reader for authorized entry
• Integrate with Home Assistant for smart home automation
• Implement visitor logging with SQLite database
• Add night vision IR LEDs for 24/7 operation
• Solar panel + battery for off-grid deployment