scan.py

import sys
import struct
import select

def parse_scanner_data(scanner_data):
    upc_chars = []
    for i in range(0, len(scanner_data), 16):
        chunk = scanner_data[i:i+16]

        # __  __  __  __  __  __  __  __  01  00  __  00  00  00  00  00
        if chunk[8:10] != '\x01\x00' or chunk[11:] != '\x00\x00\x00\x00\x00':
            continue

        digit_int = struct.unpack('>h', chunk[9:11])[0]
        upc_chars.append(str((digit_int - 1) % 10))
        
    return ''.join(upc_chars)

f = open('/dev/hidraw0', 'rb')

while True:
    print 'Waiting for scanner data'

    scan_complete = False
    scanner_data = ''
    while True:
        rlist, _wlist, _elist = select.select([f], [], [], 0.1)
        if rlist != []:
            new_data = ''
            while not new_data.endswith('\x01\x00\x1c\x00\x01\x00\x00\x00'):
                new_data = rlist[0].read(16)
                scanner_data += new_data
            
            [rlist[0].read(16) for i in range(4)]
            scan_complete = True
        if scan_complete:
            break
			
    barcode = parse_scanner_data(scanner_data)
    print "Scanned barcode '{0}'".format(barcode)