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MFRC522 RFID Reader

A project log for FIMble

Concept of a plug-and-play IoT food monitoring system. It aims to reduce food wastage at consumer and distributor level

zst123zst123 08/08/2020 at 10:280 Comments

Change of Plans

I initially wanted to use the "SparkFun Simultaneous RFID Reader - M6E Nano", however my local Sparkfun resellers do not plan to bring in any stock. I chose that RFID reader because it was a UHF long range RFID reader which will be needed if my smart inventory system is placed in a large storage space. It is unfortunate that I couldn't get one. Many other UHF RFID readers on the market are meant for industrial use and I cannot possibly afford it (costing from a few hundreds to thousands of dollars). I wanted to at least have a fully working prototype, so I had to look for alternatives.

Furthermore, I realised that the Cypress PSoC 6 Kit does not have a lot of GPIOs left. This is because the LCD display module takes up most of the pins. I found out there are no exposed hardware UART pins, SPI pins or I2C pins. (Technically, I can share I2C with the one for the KitProg).

With the constrain on the pins, I decided to choose the MFRC522 RFID Reader module which requires only SPI. SPI is very easy to bit-bang and I am familiar with the MFRC522 because I have used once when I first started with Arduino programming. 

Testing the MFRC522 Module

I first verified that my module works using the Arduino examples.

And it works, so I ported the Arduino C++ library to a C library so I can use it with my Cypress PSoC.

As for wiring, I tapped off VDD and GND from the Pmod connector. I wanted to avoid soldering, so I used long socket pins to make a friction fit.

For the SPI pins, I connected it as follows:

This is how the whole setup looks like.

Shown in the above picture is the debug screen. The RFID card UID is being read.

That is it for today. The hardware is 100% completed for this project. The next post will be to have the RFID reader upload the card detected to AWS.  I will then simulate an inventory with RFID tags and make a demo video for you to see soon!

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