These were great. Our college IDs had a barcode on them for cafeteria charge swipes.! I set up a cuecat outside my dorm door where one could swipe their ID for access, the IDs swipes would be compared against an access list and a match triggered a mechanical door opener from a locked door. Lulz all round. This was before everyone was walking around with a cellphone camera where these barcodes were marginally more secure in 2000 but the campus switched from barcodes a few years later.