I stitched together a box that can read any card with a magnet strip and, if it's on a list of registered people, turns on a relay that turns on the tool power for your shop, recording who turned it on and when ona separate file. A single person has the power to add other cards to the list. A separate key switch is available to turn tool power on an off. A large LCD screen provides information and feedback for the user. Inside it uses an Arduino Uno, USB Host shield to handle the car reader, and an Adafruit Datalogger SD Shield to handle the file manipulation.