SparkFun Electronics Forum

I want to count, maybe with OpenLog, or even a digital readout (7segment display?) when an RFID badge is scanned by my SparkFun RFID reader... I want it to be small as possible. OpenLog would be great, not sure if I use the "LED" light (turns on when a card is presented) as the trigger or if there is some other way. Basically don't want to read the card, but just the fact that someone presented the card, I want to tally that. Seems simple, I'm just not sure how small I can make such a counter, openlog is what I'm shooting for, but again I don't want to write down card details necessarily... in fact I'd like to avoid it.

Which RFID reader? SparkFun offers a few different options. It's possible that there's a "card detected" sort of output you could use.

use the "LED" light (turns on when a card is presented)

If there is such a light, go ahead and use it.

You could replace the LED with the input to an optocoupler, or tape a photocell of some sort over the LED, and use either as an input to a micro for logging.