node-red-contrib-raspi5-rc522

RC522 / MFRC522 RFID Node for Raspberry Pi 5 – pure JavaScript, no Python, no external daemon.

Supports:

• SPI0 and SPI1 (bus/device selectable)
• UID / READ / WRITE (MIFARE Classic)
• Auto polling or trigger-by-message
• Presence events: present / removed
• Dynamic wiring hints in the Node-RED editor

⚠️ Prerequisite: SPI must be enabled

This node talks directly to /dev/spidev*.
If SPI is not enabled, the node cannot work.

Enable SPI0 (standard)

sudo raspi-config

→ Interface Options → SPI → Enable

Reboot, then check:

ls -l /dev/spidev*

You should see at least:

/dev/spidev0.0

Enable SPI1 (second SPI controller)

SPI1 is not enabled by default.

Edit:

sudo nano /boot/firmware/config.txt

Add one of the following lines (example with 3 chip-selects):

dtoverlay=spi1-3cs

Reboot.

Verify:

ls -l /dev/spidev*

Expected:

/dev/spidev1.0
/dev/spidev1.1
/dev/spidev1.2   (depending on overlay)

If /dev/spidev1.0 does not exist → SPI1 is not active.

Wiring

The node editor shows dynamic wiring instructions depending on SPI0/SPI1 selection.

Typical RC522 pins:

• 3.3V (⚠️ never 5V)
• GND
• SCK
• MOSI
• MISO
• SDA / SS → chip select (CS)
• RST (optional)

Installation

Via Node-RED Palette

Search for:

node-red-contrib-raspi5-rc522

Manual install

cd ~/.node-red
npm install node-red-contrib-raspi5-rc522
sudo systemctl restart nodered

Node Configuration

Configured entirely inside the node:

• SPI Bus (0 or 1)
• Device / CS (0–2)
• Mode:
  • UID
  • READ
  • WRITE
• Auto poll + interval
• Block, Key A, Data, Verify
• Presence events (present / removed)
• Removed timeout (ms)

Output Events

Card detected

topic: "present"
payload.event: "present"

Card removed

topic: "removed"
payload.event: "removed"

Read

topic: "read"
payload.data: "<hex>"

Write

topic: "write"
payload.verified: true|false

Safety

To avoid destroying cards:

• ❌ Block 0 write disabled
• ❌ Trailer block write disabled (3,7,11,…)

Test / Debug

Check permissions:

groups
# user must be in group: spi

Add user if needed:

sudo usermod -aG spi $USER

Re-login required.

License

MIT