Gate lock and Photon


I was wanting to use a spare Photon to interface with an RFID reader and then switch power to a maglock.

I have a 3.3v > 240v relay board I can use, so I think I’m covered for the power switching to the maglock, but how are people best interfacing with RFID readers?

Thirdly, I can see there are loads ofRFID PCBs but I was hoping to buy something a little more ‘finished’ - or is it just a case of building a waterproof enclosure yourself?


(I guess I’m confused why Freetronics make a digital gatelock shield for the arduino - is it just to integrate the power switching and the interfacing into one easy to use shield?


I use HID Proximity 125 kHz prox card readers. They’re the ones often used in office buildings, and many of them are fully weatherproof. The Wiegand protocol is easy to parse on the Photon. It has 5V logic levels, and works over long distances (at least 100 feet) over twisted pair, too.

They’re a little expensive new, but you can often find used ones on eBay that have been removed from office buildings cheap.


Thanks @rickkas7 I’ve found this which looks great but I note it’s “ID” not “HID”. Is that likely to be any impediment to me? Also just wondering about the 5v logic levels on the 3.3v Photon? Would I need to somehow step down the voltage? Thanks for getting me started - that looks like a much better bet than the plain chip I’d found. Will repurpose that for a “magic cards” project.

As long as it supports the Wiegand protocol it should be compatible.

While the Photon is a 3.3V device, all of the pins (except for DAC and A3) are 5V tolerant, so you can feed the output from the prox card reader directly into the device.

This is not true for Gen 3 (Argon/Boron/Xenon) so you’ll need some level shifting there.

The code to decode the signals is here (you only need the first example, the reader):

1 Like

Just for informational purposes, I forgot about the voltage difference between gen2 and gen3 devices. I recently installed a wiegand setup using a boron, without level shifters and so far everything is working great. I’m not sure if this works for all wiegand devices, but it’s worked great for me so far.