Smart Doorbell with Camera and Audio - Electronic Engineering Guide
1. Introduction
The Smart Doorbell with Camera and Audio is an IoT-based security system designed to provide real-time video and audio communication between visitors and homeowners. It captures images/video and supports two-way audio, sending alerts and data to a smartphone or server.
2. Objectives
• Detect and notify presence at the door.
• Capture video and audio of the visitor.
• Enable real-time communication with homeowners.
• Transmit data to a mobile device or cloud for monitoring.
3. Components Required
• ESP32-CAM or Raspberry Pi
• Microphone and Speaker (or I2S audio modules)
• Push Button (Doorbell trigger)
• Power Supply (5V adapter or battery)
• MicroSD card (for local recording)
• Wi-Fi Module (inbuilt in ESP32)
• Relay (optional, for door lock control)
• Enclosure box
4. System Overview
The system activates the camera and microphone when the doorbell button is pressed. The ESP32-CAM captures the video and sends it over Wi-Fi. Audio input is recorded and streamed to the homeowner's device. Optional integration with cloud storage and mobile apps is supported.
5. Working Principle
Upon pressing the button, the ESP32-CAM initiates a video feed and audio capture. This data is transmitted via Wi-Fi. The speaker allows homeowners to respond to visitors. Integration with a mobile app facilitates two-way communication and remote monitoring.
6. Circuit Design and Interfacing
• Push button connected to GPIO with pull-down resistor.
• Camera integrated with ESP32-CAM board.
• Microphone module (analog or digital) connected to ADC/I2S pins.
• Speaker connected via DAC/I2S interface with amplifier.
• Optional relay connected for door lock mechanism.
7. Microcontroller and Camera Integration
ESP32-CAM is used for image/video capture. It includes a camera interface and Wi-Fi module. It streams live video through an HTTP server or pushes frames to a mobile app or cloud platform.
8. Audio Input/Output Setup
• Microphone captures visitor audio.
• Speaker allows homeowner to respond.
• Optional: Use audio codec modules (e.g., MAX9814 for mic, MAX98357A for
speaker) for better performance.
• Audio handled via I2S or ADC/DAC on ESP32.
9. Software and Firmware Design
• Initialize GPIO, camera, and audio interfaces.
• Setup Wi-Fi and HTTP server or MQTT client.
• On button press, start video and audio stream.
• Enable recording to SD card or upload to cloud.
• Use mobile app/web dashboard to view and communicate.
10. Power Supply Considerations
• ESP32-CAM requires 5V with at least 500mA current.
• Use regulated power adapter or buck converter from 12V.
• Battery backup optional with charging module.
• Consider low-power modes for energy saving.
11. Applications
• Home security and surveillance
• Office visitor management
• Remote video intercom systems
• Smart home integration with locks and lights
12. Limitations and Future Enhancements
• Limited video quality under low light.
• Latency in video/audio streaming.
• Future improvements: night vision, motion detection, AI-based face
recognition, cloud sync, app integration.
13. Conclusion
This smart doorbell system combines embedded electronics and IoT to offer a modern, automated, and secure visitor interface. It enhances safety, convenience, and connectivity for smart homes.