MSB Door Lock Sensor

ESP32-C3 Super Mini based door lock sensor using a reed switch. Reports lock state to Home Assistant via MQTT auto-discovery.

Hardware

• ESP32-C3 Super Mini
• Reed switch (N/O, normally open)
• Magnet (mounted on lock bolt)

Wiring

ESP32-C3 Super Mini        Reed Switch
───────────────────       ──────────
GPIO3 ──────────────────── Pin 1
GND   ──────────────────── Pin 2

Internal pullup enabled — no external resistor needed.

Magnet	Switch	GPIO	State
Present	Closed	LOW	LOCKED
Absent	Open	HIGH	UNLOCKED

Setup

1. Install PlatformIO

2. Copy the sample config and fill in your credentials:

   cp include/config.sample.h include/config.h

3. Edit include/config.h with your WiFi and MQTT broker details

4. Build and flash:

   pio run -t upload

5. Monitor serial output:

   pio device monitor

The sensor registers itself in Home Assistant automatically via MQTT discovery.

Project Structure

├── platformio.ini          # PlatformIO config
├── src/
│   └── main.cpp            # Firmware: WiFi + MQTT + reed switch
├── include/
│   ├── config.sample.h     # Template config (tracked)
│   └── config.h            # Your config with credentials (gitignored)
├── RESEARCH.md             # Hardware research notes
└── BOM-ALIEXPRESS.md       # Bill of materials

Roadmap

• Deep sleep with GPIO wakeup for battery operation
• Battery voltage monitoring via ADC
• OTA firmware updates
• Multiple sensor support

License

MIT