Raspi RFID scanner

## cards.json
{
    "170038E91C": "1003729691",
    "17003F5A1D": "1004151834"
}

## requirements.txt
ipython==1.1.0
python-ldap==2.4.13
requests==2.0.1

## scanner.py
import logging
import pifacedigitalio
from evdev import InputDevice, categorize, ecodes
from utils import switch_relay, check_id

# setup logging
logging.basicConfig(format='%(asctime)s %(levelname)s: %(message)s',level=logging.DEBUG)
logging.info('rfid scanner starting')

# connect to the piface
p = pifacedigitalio.PiFaceDigital()
p.relays[0].turn_off()
logging.info('Turned relay off')

# connect to rfid device for events you can find the correct device with `lsusb`
dev = InputDevice('/dev/input/event0')

badge_no = ''
logging.info('Listening for rfid events')

# every time a card is scanned, a 'keystroke event' will be fired for every character of the card, we need to
# listen for this, and group all the events together, untill we receive a newline (enter) key. Then we can
# check all the previous characters in 'badge_no' if it was correct
for event in dev.read_loop():
    if event.type == ecodes.EV_KEY:
        event_cat = categorize(event)
        if event_cat.keystate:
            # if we received an ENTER, we check the previous string since
            # the last time an ENTER was received
            if event_cat.keycode == 'KEY_KPENTER':
                logging.info('Received %s' % badge_no)

                # is access granted?
                if check_id(badge_no):
                    switch_relay(p.relays[0])

                # reset for new input
                badge_no = ''
            else:
                key = event_cat.keycode
                key = key.replace('KEY_', '')
                badge_no = badge_no + key

## supervisor.conf
[program:scanner]
command=/home/svdgraaf/rfid/scanner.py
autostart=true
autorestart=true
redirect_stderr=true
stdout_logfile=/var/log/rfid-scanner.log
stderr_logfile=/var/log/rfid-scanner.error.log
directory=/home/svdgraaf/rifd/

## utils.py
import logging
import time
import json
import requests

# setup logging
logging.basicConfig(format='%(asctime)s %(levelname)s: %(message)s',level=logging.DEBUG)

# if the access_string is in the cards file, access is granted
def check_id(access_string):
    json_data=open('cards.json')
    data = json.load(json_data)

    if access_string in data:
        logging.info('ACCESS GRANTED')
        return True
    else:
        logging.info('ACCESS DENIED')
        return False

# open the correct relay
def switch_relay(relay):
    logging.info('Opening Relay')
    relay.turn_on()

    # keep relay open for 3 secs
    time.sleep(3)
    logging.info('Closing Relay')

    # close the relay
    relay.turn_off()
    return True