Proxmark3 Easy Case and modification

Projects
1

Thanks to @DonFire 's excellent guide I got my Proxmark back up and running.

Since then I’ve been playing around with all of the things I can do with it. One of my main concerns with the board was the lack of a proper case. Knowing me, I was bound to short something and make the device more brick-like than my botched firmware update did.

So I started designing a case for it and while I was thinking about the design I had a realization. The middle PCB is barely useful. It raises the LF antenna away from the main PCB and covers the traces of the HF antenna. This got me messing around with a variety of orientations and attachment methods for the LF antenna. What I found was the higher the antenna was from the main PCB the higher the Q factor would go with the opposite happening if the antenna was placed so only one set of standoffs separated them. This led me to finding a more minimal case design and a practical mod. Rotate the LF antenna so it is over the HF antenna and remove the middle PCB all together. This reduces the Proxmarks height from 15.8mm down to 11.5mm. The only downside is having to flip the Proxmark over or placing it on top of HF tags to be read which I find an acceptable compromise.

I also found the new orientation lead to better performance when reading or writing the LF side of my NEXT. The hw tune command shows the Q factor increased by approximately 12%

Stock Vs. Modified

unmodified:

hwtune-unmoded
hwtune-unmoded1269×538 22.3 KB
Modified:
hwtune-moded
hwtune-moded1281×552 22.4 KB

The Case

IMG_20210119_022608
IMG_20210119_0226084000×3000 4.11 MB

Important notes:
The middle holes are bigger to accept a pair of the original standoffs. Those standoffs are required as they are part of the circuit for the LF antenna. Also note the arrows on the antenna board should always be over the middle holes on the Proxmark. For the rest of the attachments I used Phillips head countersunk M2x10 screws from the bottom to the top 4 holes of the antenna. The last two holes are Phillips head countersunk M2x6 with M2 hex nuts melted into the plastic.
proxmark3easycase.zip (226.8 KB)

4 Likes
2

I’ll be adding this to my print que

3

Could you post a pic of the reordered PCB stack? I think i get what you mean, but just wanting to make sure I’m on the right track.

This could very well be the way i set mine up going forwards!

1 Like
4

Sure. It looks like this:

IMG_20210119_042330
IMG_20210119_0423304000×3000 2.98 MB

5

Have you given any thought to the lf underneath and upside down the Hf with no stand offs?

6

Definitely makes it much slimmer!

1 Like
7

hmmmm an interesting idea. I’ve tested it out real quick and I can definitively say that Its easy to get a read and the antenna is only a millimeter or two away from the HF antenna. I will get a new case printed out and post an update tomorrow.

Edit: I was wrong about it still being easy to read. That 2mm makes a difference with reading a NEXT.

8

Might be a good idea to update it with a ‘window’ in that case? Something with beveled edges as it would make it more comfortable on your hands when you lay your implant close to the reader.

9

So what’s the consensus about flipping the lf to the bottom of the board?

10

It works great if you’re reading standard cards or fobs. It does decrease the effectiveness of the HF antenna though.