tk4100-rfid-reader

Read cards from a USB TK4100 / EM4100 card reader

Only tested on Raspberry PI but should work on any Linux OS. I personally used this reader from Amazon.

• SainSmart RFID Mifare IC Card Reader USB for TK4100/ EM4100/ EM4200 (13.56M 1443A (2H+4H))

Usage

As a module

First, install the module

npm install tk4100-rfid-reader

Then use it like:

var RFIDReader = require('tk4100-rfid-reader');
 
var rr = new RFIDReader({
   device: '/dev/input/event0', // input device to read
   maxLength: 32 // max key length, defaults to 32, set to 0 to disable
});
 
rr.on('tag', function (tag) {
    // tag as a hex string
    // tag => "abcd1234"
});
 
rr.on('error', function (err) {
    // error was encountered while reading
    // currently this is only fired if the key is greater than maxLength
});

As a command line tool

The tk4100-rfid-reader command will listen for new tags being read by the reader, and then fork an external command for each new tag ran in order.

Install the tool globally

npm install -g tk4100-rfid-reader

Then create a JSON config file

{
    "device": "/dev/input/event0",
    "exec": {
        "file": "./new-tag",
        "options": {
            "timeout": 30000,
            "uid": 1000,
            "gid": 1000
        }
    },
    "log": {
        "level": "debug",
        "name": "rfid-reader"
    }
}

• device: the device passed to the RFIDReader constructor to listen for events
• exec.file: command to execute for each new tag detected
• exec.options: exec options - passed directly to child_process.execFile
• log: passed directly to the bunyan constructor for logging

And finally create the ./new-tag script - this will be executed whenever a new tag is read.

#!/usr/bin/env bash 
tag=$RFID_TAG_ID
echo "running command as $(whoami) for tag $tag"

This program will be executed with the environmental variable RFID_TAG_ID set.

Example

# tk4100-rfid-reader config.json
[2018-07-16T21:03:06.269Z]  INFO: rfid-reader/5970 on garage-pi.rapture.com: watching for events on /dev/input/event0
[2018-07-16T21:03:08.605Z] DEBUG: rfid-reader/5970 on garage-pi.rapture.com: read tag "abcd1234"
[2018-07-16T21:03:08.615Z] DEBUG: rfid-reader/5970 on garage-pi.rapture.com: executing "./new-tag"
    opts: {
      "env": {
        "TERM": "xterm-256color",
        "SSH_AUTH_SOCK": "/tmp/ssh-P0FEDWaaeL/agent.1566",
        "PATH": "/opt/custom/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/home/dave/bin",
        "TZ": "US/Eastern",
        "HOME": "/home/dave",
        "SHELL": "/bin/bash",
        "MAIL": "/var/mail/root",
        "LOGNAME": "root",
        "USER": "root",
        "USERNAME": "root",
        "SUDO_COMMAND": "./tk4100-rfid-reader config.json",
        "SUDO_USER": "dave",
        "SUDO_UID": "1001",
        "SUDO_GID": "1003",
        "RFID_TAG_ID": "abcd1234"
      },
      "encoding": "utf8",
      "timeout": 30000,
      "uid": 1000,
      "gid": 1000
    }
[2018-07-16T21:03:08.658Z] DEBUG: rfid-reader/5970 on garage-pi.rapture.com: execution succeeded (stderr="")
    stdout: running command as pi for tag abcd1234

License

MIT License