Plug a reader into the headers, use a Qwiic cable, scan your 125kHz ID tag, and the unique 32-bit ID will be shown on the screen. The unit comes with a read LED and buzzer, but don't worry, there is a jumper you can cut to disable the buzzer if you want. Utilizing SparkFun's handy Qwiic system, no soldering is required to connect it to the rest of your system. However, we still have broken out 0.1"-spaced pins if you prefer to use a breadboard.
Utilizing the onboard ATtiny84A, the Qwiic RFID takes the six byte ID tag of your 125kHz RFID card, attaches a timestamp to it, and puts it onto a stack that holds up to 20 unique RFID scans at a time. This information is easy to get at with some simple I²C commands.