Detailed Working of μRFID with Base Board

This tutorial shows how to get started with the rhydolabz μRFID Base Board cum EM-18 μRFID reader. Radio Frequency Identification uses radio waves to detect the presence of  an RFID tag. Here the module works on 125KHZ, it can detect any RFID card within range and with the frequency same as that of its working frequency.


  • Onboard µRFID reader module
  • Operating frequency 125kHz
  • Current Rating < 50mA
  • Reading distance 10–15 cm
  • Communication parameters 9600bps, 8-N-1
  • Supports Tags which work at 125kHz
  • USB, RS232 (DB9) and TTL Interfaces for serial RFID data
  • Jumper Selection for output format: Serial & Wiegand 26
  • Wiegand 26 output pins brought out on board
  • DPDT slide switch to select between USB and DB9 output
  • LEDS for visual status indication; Power and Tag Detection
  • Audio alert on tag detection
  • Multiple options for powering; via USB port, DC barrel jack or RMC connectors
  • 5V on board regulation for DC power input
  • Fuse protection when USB powered
  • DC voltage input: 7~9V

How to power μRFID Base Board?

You can power the μRFID Base  Board by one of the following ways-

  1. Through the DC barrel Jack (any standard 9-12V Adapter)
  2. Through the miniUSB port
  3. Through the RMC connector (7-12V power supply) 

The power source is selected as DC / USB by the jumper J1. If DC source is selected, you can power the board via 2-pin RMC connector or DC barrel jack. Once the board is powered, the PWR LED (red) on the board [shown in the image below] glows.

How to Communicate with μRFID Base Board?

The μRFID Base Board communicates over UART (TTL serial / RS232) or Wiegand26 protocol. The SEL pin of RFID reader helps to select the required protocol.

  • The base board is configured for UART interface when J2 is open (SEL pin HIGH).
  • To change the output to Wiegand, place jumper J2 in position (SEL pin LOW).

Now wave a card over the reader. You can hear the beep sound of the buzzer and see the STS LED (Green) blinking. These are triggered automatically by the BUZ pin of the module that goes low on detecting a valid card. Also you can read the card no: either in serial / Wiegand format by making proper selections as mentioned above.

UART (TTL serial / RS232)
The detected tag data can be read from DB9 connector (RS-232), USB port or the RMC pins (TTL Serial). The DPDT slide switch allows you to select between USB or DB9. If you are interested to communicate via USB (Please go through the link CP210X Virtual Com Port (VCP) driver Installation).

Wiegand 26
The output can be obtained from the RMC pins (K2) only.                                                                                          Note that the RMC connector provides output in both the formats.The connector pin out is shown below.


Suggested Materials

To follow along with this tutorial, You will need the following:


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