/*

ABOUT
-----
Use NodeJS to read RFID ids through the USB serial stream. Code derived from this forum:
http://groups.google.com/group/nodejs/browse_thread/thread/e2b071b6a70a6eb1/086ec7fcb5036699

AUTHOR
------
Chris Basham
@chrisbasham
http://bash.am
02/01/2011

SOFTWARE
--------
NodeJS, version 0.2.6
http://nodejs.org

HARDWARE
--------
Sparkfun RFID USB Reader
http://www.sparkfun.com/products/8852

RFID Reader ID-20
http://www.sparkfun.com/products/8628

EM4102 125 kHz RFID Tags
http://www.trossenrobotics.com/store/p/3620-Blue-Key-Fob.aspx

*/

var sys = require('sys');
var fs = require('fs');

// This will be unique to your hardware.
// List your available USB serial streams via terminal and choose one:
//   ls /dev | grep usb
// Had trouble with TTY, so used CU.
var serial = '/dev/cu.usbserial-A600exqM';
// Simplifies restruction of stream if one bit comes at a time.
var f = fs.createReadStream(serial, { bufferSize: 1 }); 

var id = '';

f.addListener('open', function(fd) { 
	sys.puts('SCAN RFID TAGS');
	sys.puts('--------------');
});

f.addListener('data', function(chunk) { 

	var c = chunk.toString('ascii').match(/\w*/)[0]; // Only keep hex chars
	
	if ( c == '' ) { // Found non-hex char
		if ( id != '' ) // The ID isn't blank
			sys.puts(id);
		id = ''; // Prepare for the next ID chunks
		return;
	}
	
	id += c; // Add to the ID

});