rfid-rc522

RFID RC522 on Raspberry PI with NodeJS

node.js module to access a rfid reader with rc522 chipset which is connected a raspberry pi

This is mostly a rewrite of the rc522-rfid module, very little of that (and none of its API) have made it across.

However, that does mean that this version can read and write data to Mifare Ultralight (and related types, such as NTAG2xx) tags.

Purpose

This node module is to access RFID reader with a rc522 chipset (e.g. http://amzn.com/B00GYR1KJ8) via GPIO interface of the raspberry pi.

Installation

1. Install node:

curl -sL https://deb.nodesource.com/setup_0.12 | sudo bash -
sudo apt-get install -y nodejs

2. Update your PI:

sudo apt-get update
sudo apt-get upgrade
sudo apt-get dist-upgrade
sudo rpi-update
sudo apt-get clean

3. Configure the PI:

The RFID reader is plugged onto the raspberry pi like it is described over here http://geraintw.blogspot.de/2014/01/rfid-and-raspberry-pi.html

• The GCC compiler is installed sudo apt-get install build-essential
• node-gyp is installed sudo npm install -g node-gyp

4. Compile the spi_bcm2835 driver:

First of all we have to install the C library for Broadcom BCM 2835 as it describe` here

wget http://www.airspayce.com/mikem/bcm2835/bcm2835-1.49.tar.gz
tar -zxf bcm2835-1.49.tar.gz
cd bcm2835-1.49
./configure
make
sudo make check
sudo make install
sudo modprobe spi_bcm2835

5. Make a node project

cd ~/
mkdir RFID
cd RFID/
npm install --save rc522
nano rfid.js

TODO: Include an example program to demonstrate the functionality. For now, you'll have to look at the code, I'm afraid - the module exports readPage and readPageAsync which read pages from an Ultralight tag (a page is 4 bytes); writePage and writePageAsync to write pages to an Ultralight tag; registerTagCallback which sets a callback which is called whenever a tag is detected; and readFirstNDEFTextRecord which extracts NDEF formatted text record from an Ultralight tag.

Save and run: (Is necessary "sudo")

sudo node rfid.js

NOTE: Running as root

Prior to the release of Raspbian Jessie in Feb 2016, access to any peripheral device via /dev/mem on the RPi required the process to run as root. Raspbian Jessie permits non-root users to access the GPIO peripheral (only) via /dev/gpiomem, and this library supports that limited mode of operation.

If the library runs with effective UID of 0 (ie root), then bcm2835_init() will attempt to open /dev/mem, and, if successful, it will permit use of all peripherals and library functions.

If the library runs with any other effective UID (ie not root), then bcm2835_init() will attempt to open /dev/gpiomem, and, if successful, will only permit GPIO operations. In particular, bcm2835_spi_begin() and bcm2835_i2c_begin() will return false and all other non-gpio operations may fail silently or crash.