An RFID based relay control system. Tap an authorized card to toggle a 5V brushless fan ON or OFF via a relay module.
| Component | Model |
|---|---|
| Microcontroller | Raspberry Pi Pico 2 |
| RFID Reader | MFRC522 (SPI, 3.3V) |
| Relay Module | 1 Channel Active Low |
| Fan | 5V Brushless |
| Pico 2 Pin | MFRC522 Pin |
|---|---|
| 3V3 | 3.3V |
| GND | GND |
| GP18 | SCK |
| GP16 | MISO |
| GP19 | MOSI |
| GP17 | SDA/SS |
| Pico 2 Pin | Relay Pin |
|---|---|
| VBUS (5V) | VCC |
| GND | GND |
| GP2 | IN |
| Relay Pin | Fan |
|---|---|
| COM | -ve |
| NO | Fan - |
main.py - main loop: scan card, toggle relay
mfrc522.py - cefn/micropython-mfrc522 driver
- Authorized card tap → relay toggles ON, fan starts
- Same card tap again → relay toggles OFF, fan stops
- Unknown card → Unknown card printed on serial
- Relay is active low — GP2 LOW = relay ON, GP2 HIGH = relay OFF
- Debounce of 2000ms prevents repeat reads
Day 74 - RFID Relay Control
Hold card to toggle fan...
Fan: ON
Fan: OFF
Fan: ON
Unknown card
Kritish Mohapatra
B.Tech Electrical Engineering (3rd Year)
IoT | Embedded Systems | MicroPython | ESP32
If you like this project, give it a ⭐ on GitHub and feel free to fork it!
Happy hacking 🚀