Jumping In At The Deep End

To gather some hands-on experience with RFID technology, and to eventually build a first prototype of an Rfish reader, I did order Grand Idea Studio’s Serial RFID Module which is available as item #28140 from the Parallax web store for $39.99 (discounts apply for orders of five or more). From an earlier project I have a BlueSmirf Gold Bluetooth Module, sold by SparkFun for $64.95 and an USB to Serial Adapter similar to the FT232RL for $14.95, SparkFun as well.

After reading the Data Sheet of the the Parallax module it seemed that some additional circuitry is necessary to connect the 5V RFID reader to the 3.3V BlueSmirf module. Lacking even the most basic hardware skills I thought that this could already be the end. Google brought up several projects connecting an RFID module to a Laptop or a controller like the Arduino, but only after a while I found Knut’s Bluetooth RFID reader, the project by HC Gilje and some comments hinting at a similar effort by David from Blendid. Thanks to their encouragement I had another look at SparkFun’s product page and finally realized that the BlueSmirf module can be powered from 3.3V up to 6V for easy battery attachment. So all there was left to do was setting the BlueSmirf to 2400 baud and throwing together a test program that reads from the COM port. Half an hour later the console on my laptop displayed the first few RFIDs – received over Bluetooth, straight from the Rfish reader.


The Parallax Serial RFID module and the BlueSmirf Bluetooth module where connected through direct wires (sout to rx-i, /enable to rts-o, vcc to vcc and gnd to gnd) and powered by the same battery pack (three AA LR6 1.5V cells). While this might not be the ideal setup it is at least a proof of concept. Once again it paid out to eliminate the biggest risk first – today was a good day.


Creative Commons License This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 2.5 Switzerland License.


One Response to “Jumping In At The Deep End”

  1. Rfish Reader Prototype « rfish blog Says:

    […] rfish blog I R Fish « Jumping In At The Deep End […]

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