RFID presence

Hi all,

I'm using this at the moment http://www.seeedstudio.com/depot/electronic-brick-125khz-rfid-card-reader-p-702.html?cPath=144_153 and it's going fine.

However, the one limitation is that if I ask it whether it has can see a tag, it will only respond yes once while the tag is present. For this project, I need to know if the tag is there whenever I make the request, even if the tag hasn't moved.

This tutorial (http://bildr.org/2011/02/rfid-arduino/) covers the concept quite well but there is no reset wire on my device. How can I get it to tell me the ID whenever I request it?

Thanks,

Gausie

Basically with that reader you can't.
It is a function of the logic inside the reader. The token is constantly read but only the first reading is transmitted. Use another reader or build your own.

Can you reset it by having the arduino cycle the power to it?

I suppose you could but it might not initialise until the token is out of the field, but I don't know.
The problem could be that it takes a few seconds to initialise on start up. You need to experiment with your reader. I did have a look on the web site and the answers to questions are best described as evasive.

Thanks for the responses.

Grumpy_Mike:
Use another reader or build your own.

Can you suggest a reader that would be appropriate? Is building my own a significant undertaking?

wildbill:
Can you reset it by having the arduino cycle the power to it?

Can I cycle the power without getting a relay involved?

Gausie