RFID (radio-frequency identification) is the wireless non-contact use of radio-frequency electromagnetic fields, for the purposes of identifying and tracking tags attached to objects. This is the ID-3LA, a very simple to use RFID reader module from ID Innovations. The only holdups are the 2mm pin spacing (breakout board available below) and you will need an external antenna. Power the module, hold up a 125kHz card, and get a serial string output containing the unique ID of the card.
The new ID-3LA is essentially the same as the ID-2, but has a lower voltage input.