Multi Reader Wiegand 4 bit, 8 bit, 24 bit, 26 bit, 32 bit and 34 bit library for Arduino
The Wiegand interface is a de facto standard commonly used to connect a card reader or keypad to an electronic entry system. Wiegand interface has the ability to transmit signal over long distance with a simple 3 wires connection. This library uses interrupt pins from Arduino to read the pulses from Wiegand interface and return the code and type of the Wiegand.
Why another Wiegand library?
The original Wiegand library was written to support a single wiegand reader for an Arduino UNO. As time goes by, gathered by the requests from users, I wrote another Wiegand NG library to solve readers that send out non-standard bit length wiegand data. Due to different methods used in storing the raw data, the two library were maintained in different repos.
This Multi Wiegand library was a modified version of the original Wiegand library written to support C++ objects so that the same object can be reused by multiple wiegand readers and yet with the variables stored in the individual object's memory.
The reason why when I first wrote the original Wiegand library I did not write the library in pure C++ object method was because Arduino attachinterrupt cannot be attached to class method directly and I also wanted the first library to be clean and simple to use instead of adding hacks and workaround like this library does.
Different Wiegand libraries comparison
| Library | Description |
|---|---|
| Wiegand library | This is the easiest and cleanest library to use when only a single wiegand reader is needed. I strongly suggest to use this version if you only need one reader support |
| Wiegand NG library | This is another single reader library, however it uses dynamic memory to store the raw wiegand thus allowing unlimited bit length to be stored as long as your Arduino board has the memory to store it. I won't recommend to use this library unless you are facing a non-standard wiegand reader that sends out data that will not be decoded by the original Wiegand library. |
| Multi Wiegand library | This library uses pin change interrupt, thus allowing all the pin change interrupt supported pins to be used. With this, multiple readers can also be supported. Due to a workaround (hack) used to overcome the limitation with attachInterrupt not being able to be attached to the class method directly, the initialisation of the sketch is more ugly and complicated. |
NON Standard Bit Length
This library was designed to decode standard Wiegand protocol with 1 START bit, 1 STOP bit and bit length stated in the title. For multi-bit length protocol, please try Wiegand NG Multi Bit Wiegand Library for Arduino.
Requirements for the Example to Work
The following are needed
- Arduino - Any ATMEGA328 compatible board should work.
- Pin Change Interrupt Library
- Wiegand RFID Reader - The code was written for this reader however customers reported working with HID compatible readers.
- DATA0 of the first Wiegand reader connects to Arduino PIN 2 and DATA1 of the first Wiegand reader connects to Arduino PIN 3
- DATA0 of the second Wiegand reader connects to Arduino PIN 4 and DATA1 of the second Wiegand reader connects to Arduino PIN 5
Installation
Create a folder named WiegandMulti in Arduino's libraries folder. You will have the following folder structure:
cd arduino/libraries
git clone https://github.com/jpliew/Multi-Reader-Wiegand-Protocol-Library-for-Arduino.git WiegandMultiArduino Sketch
Execute Arduino IDE, select Example-->WiegandMulti-->WiegandTest
Example
Please see example in the example folder.
Contributors
softwarefoundry added library.properties
Francesco Uggetti (ugge75) improved this version of library to support multiple readers for ATMEGA2560. Please check out his version of multiple wiegand readers library here
Apollon77 improved interrupt safety and removed sysTick from global
paulfurley added 4 bit code
PaulStoffregen added Use digitalPinToInterrupt on newer Arduino software, if present
tholum Simpler Instructions
zanhecht Recognize 24- and 32-bit
luckymallari Simplified begin(D0, D1) for ESP(8266/32) devices.
Written by JP Liew
Project home: http://www.monkeyboard.org/tutorials/82-protocol/24-wiegand-converter
This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.