SNARC: A Networked RFID Controller

I just got my hands on a first prototype version of the SNARC (Simple NetworkAble RFID Controller) designed by Lawrence “Lemming” Dixon at the Hackerspace Brisbane (HSBNE).

SNARC provides a simple platform for network controlled RFID access. It has a microcontroller, Ethernet module, connector pins for an RFID reader (5V,TX,RX,GND) and an N Channel MOSFET output on board. This makes it a convenient solution for applications where a device needs to be powered or triggered via an RFID card while its access rights are stored somewhere in the cloud, e.g. doors in office buildings etc.

SNARC comes with an ATMega328p chip and Wiznet Ethernet module (both of which are used by Arduino as well), which makes it fully compatible to the Arduino platform. The ATMega chip comes with an Arduino bootloader, i.e. you can use your Arduino IDE and run Arduino sketches on the board, by simply uploading them through an FTDI cable.

I have previously developed a networked RFID solution with an Arduino Uno, Ethernet Shield and ID-20 RFID reader, which is basically capable of doing the same thing, but nowhere as compact and easy to setup as the SNARC. The fact that SNARC bases on Arduino, makes it an easy to use enabler for DIY Internet of Things solutions. A minor disadvantage is that you still need to physically connect it to an Ethernet cable. I would like to see SNARC further developed with a WiFi or Zigbee interface at some stage.

Find more information about SNARC on the Brisbane Hackerspace Website (http://www.hsbne.org/projects/SNARC) and example code on github (https://github.com/davidbuzz/snarc). SNARC is not released for official sale yet, but apparently will be soon. So stay tuned. Or shoot HSBNE an email if you’re interested to get a prototype.

I am working on a checkin-system at the moment, which enables visitors in a public library to leave digital footprints of their profile information at particular “checkin points”. I use SNARC at these checkin points to read a user’s RFID card and submit a GET request to my server URL with the RFID value of the card attached as a parameter.

The Electronic brick – 125Khz RFID Card Reader from Seeedstudio serves as an RFID reader in this application. It’s cheap, very easy to connect and there is an existing Arduino library for it (https://github.com/johannrichard/SeeedRFIDLib). The connection between SNARC and the RFID reader is 3 wires only: GND, +5V and the RFID reader’s TX to SNARC’s RX. You can ignore the RFID reader’s RX; as we are only reading cards, the data flow is exclusively from the RFID reader to the Arduino. SeeedRFIDLib uses SoftSerial, so you can use any available Digital Pin as Tx on the SNARC.

Find my code for this application on github: https://github.com/markbil/NetworkedRFIDController

The code is fully compatible to an Arduino 1.0+ with Ethernet Shield, if you don’t have a SNARC. A little buzzer on pin 19 provides feedback when a card is read and two LEDs (green on pin 5 / red on pin 6) indicate successful/failed connections to the server. If you use a SNARC, the sketch provides feedback through the two onboard LEDs.