Revisiting not-so-great readers

I was cleaning around in the workshop and found a bunch of discarded RFID / NFC readers that I don’t use anymore, or never even used once, because their performances range from meh to not working at all with glass implants. I decided to revisit them and see how they work with Flex implants:

  • Elatech MultiTech TWN4: this is a dual-frequency reader. It’s functional but a bit too finicky for my taste with LF and HF glassies. But the performances with flexies are really quite good: I get 1/2" of range with a flexNT or a flexDF2 (not quite enough to read through my finger or my hand though), and a solid 2" with a flexEM. Hmm… I might actually press that one back into service because its firmware is infinitely configurable and blows any other reader’s I’ve seen on the market out of the water.

  • Promag PCR300: this one sucks monkey ass even as a regular card reader. It still sucks with a flexEM, but at least it picks it up, which is more than can be said of its ability to pick up glass implants. The range is barely 1/4". Back into storage it goes. I haven’t thrown it away yet out of respect for the environment to be honest.

  • uTrust 3700F: okay with NFC glassies. I stopped using it only because why bother when the ACR122U with the same form factor works better. But it works great with flexies: I get 1/2" of range with the flexNT and the flexDF2. But crucially, it reads the flexNT through my finger with ease. That one’s definitely going back onto my desk.

  • ACR1281U-C2: this very disappointing NFC keyboard wedge proves that ACS also makes shit products. It plain don’t work with glassies, and it gets less than 1/2" with the flexNT or flexDF. It doesn’t read the flexNT through my finger. It keeps disappointing, so it goes back into the cardboard box of oblivion also.

  • Feitian R502 (not to be confused with the very good Feitian R502-CL): unusable with glassies, unusable with flexies also. Seriously: it only gets a read off of either the flexNT or the flexDF2 once in a blue moon, after carefully searching the sweet spot and ramming my hand hard against the surface. Surely Feitian went out of their way to make this one this bad. Surely… When you know what they can do when they try…

Anyway, I thought some of you might be interested in those results. It goes to show that flex implants can rescue an otherwise unusable or disappointing reader, and can even make a slightly boring one a really good one. If I find more stuff in my junk pile, I’ll retest it here.


You must be extremely precise with your hand movements. A couple of mils is amazing, if it was millimeters, it wouldn’t be as impressive! :crazy_face:

Engineering jokes aside, I’m surprised that someone managed to make a reader that’s so bad that it can’t even read flex implants…

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It’s even worse than that: I kind of assumed “mils” was an informal but accepted abbreviation for millimeters, but I just looked it up and it really means milliliters :slight_smile: Funny, I’ve always said mils for millimeters, and everyone I know does too.

Yeah Feitian is really deceitful with those R502. I bought two of the damn things, thinking they were R502-CLs with a contact card reader tacked on. But no: they’re their own particular hateful species of reader that just happen to share the same name as another, totally different kind that works great.

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That’s something I didn’t know, thank you.

It also means “thousands of an inch”. This unit is also referred as “thou”.

And this also means that my brilliant joke was not brilliant at all! FSM damm it! :man_facepalming:t2:

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Speaking from a country of metric, it is very common, to use mils for both, they are interchangeable and logical when talking about a liquid it millilitres and measure of distance millimetres.

Also used on a compass being 6400mils in a circle for accuracy ~18 mils to 1⁰

short for milliradian if you were wondering

This one is bizarre beyond belief: I’m checking out Identiv’s latest offerings, in case they have some new cool RFID hardware, and I hit their Youtube channel. And this is what I found:

Apparently they found a moderately convincing Tom Cruise lookalike and the marketdroids decided it would be a good idea to make an entire series of promotional videos for their products based on the guy’s lackluster imitation skills.

Jesus… Who authorized this? :slight_smile:

And another of my disused readers:

  • ACR122T: it’s actually a very good little reader, this. It’s the pocket version of the ACR122U. It works great with glass implants. I quit using it because I don’t travel all that much anymore. Sadly, it turns out it’s not all that great with flex implants: it works fine, but it gets only a little over 1/4" range with the flexNT and flexDF2. Unexpected considering how well it works with glassies.

So I got the ACR122T and experimented a bit with the location of the antenna. And I managed to get a range of about 1.5cm with a key fob around the area of the blue cicle I added to this picture:

I assume that this is the general location of the antenna on this thing and hope that it’s helpful.