Compatibility with Animal chips

Hi there,

It was recommended that I post here after commenting on Kickstarter enquiring if this would support pet microchips which operate at 134kHz.

These are common in Australia along with i believe a lot of countries - basically most if not all pets get a tag implanted, and if that pet is lost/runs away and loses their collar, any vet can ‘scan’ the tag in the pet and see its serial number which links to a database with the owners phone number.

In terms of compatibility, the first question is if the antenna is putting out enough power to couple well with small glass tags - this has two benefits, it would work on pet tags, and also human RFID implants since they are the same form factor.

Normally getting compatibility with both sorts of tag is pretty easy from a hardware standpoint, instead of aiming for your antenna to be tuned to 125kHz, a lot of people aim for 129-130kHz - this is usually close enough to 125 and 134 to work well for either.

This is done for most Proxmark stock antennas with good success. Another idea is that an extra ‘tuning capacitor’ could be added to the receive circuit and switched in software with a transistor, so the coil could be tuned to 125, and it could ‘detune’ to read 134 - but this is often unneeded.

You can also find me on the Dangerous Things forum - where a lot of implants are discussed - If you would like, i can try and organise for some chips to be sent to you to test with your antenna design!

Thanks, let me know if you would like more details!


This is also common in Europe, and I would like to see this feature!
But I think this mod works becouse the proxmark has enough power to overcome the inefficiency from having the antenna frequency not quite matched?
The tuning capacitor seems like it would be a more reliable on low powered hardware but I don’t know how involved this change to the design would be.

I think this is an important feature!

This would be a great feature!

I agree that having a sufficiently powerful RFID hardware setup would be critical to make it work, but you’d need that to couple with the small glass tags anyway regardless of the slight difference in frequency.

And to my understanding, the chip used can pump out plenty of power, check out the HydraNFC.

Normally you’d decrease power in a battery powered device, but since it won’t be constantly reading, and has a user interface to request a scan, i don’t see why it couldnt put out more power on a read to make this work. That said, I’ve never had the hardware in my hands, so this is all speculation until @zhovner or someone on the team can test.

its very common to add several capacitors with MOSFETs to tune the antenna. maybe it needs to add this here. it have very small footprint.

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I’ve been playing with a project relating to this. I’ve been trying to use RFID reader boards, not build something new. This guy’s video is probably the best I’ve seen.

When he measures his antenna, he’s using a LTR-R4, not anything special. Someone better than me with RF could make recommendations, but it looks like his method works.

For mine, the RFID readers I’ve tried so far had pathetically short range. I thought I’d either read the cat’s implant, or a collar device. The chips move, so it becomes hard. If you’ve ever seen a vet scanning cats, you’ll see that their professional devices have a hard time reading them.

I did get the better board that he used in the video, but the first one arrived damaged. Like, components ripped off the board damaged. The vendor sent a free replacement, but I haven’t had time to hook it up to try.

On Flipper, it may be a desirable feature, but hard to implement well. Just dropping that board inside would add bulk. Setting it up to use over a GPIO should be easy. It could probably be put in a friendly plastic case, so it’d look better than just a PCB dangling off it, with a separate wired antenna for scanning with.

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Yeah I’d be concerned about reliability with the antenna on the flipper. That’s why proxgrind came out with the Ferrite antenna specifically for implants. I have trouble sometimes with the LF implant I have on the proxmark3 rdv4. I usually get better results with the Proxmark3 Easy antenna since I don’t have that newer one for the rdv4. I went with the HF flex antenna implant and that doesn’t have any issues with the stock antenna’s so I’m confident the flipper should be good for the flex HF implants.

Just saying, that would be a nice extra feature on flipper0, I’m in europe and would like to be able to use my flipper0 to find the owner of a lost pet without having to take it to the vet.

Yeah it should work in theory but just saying the antenna may be an issue depending on the size of your implant.

The changes to the antennas don’t look promising…
Any insights on the performance difference with xSeries implants

Looks like the coil one you circled is the Sub 1G antenna, not for RFID. It’s still there in the new design too. Just looks like the wire wound antenna is being replaced with PCB trace antennas. Depending on clearance to back case I’m not too confident either

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Right you are good sir, nice spotting :+1:

It doesn’t look like there are any stand-offs, so if they are flush, they may work okay.

I would love to hear if @koteeq has done any testing

I believe it doesn’t really help to add here, but I would be a great fun of this feature. The product would be an instant get for me if this could be implemented!