Raspberry Pi Zero Compatibility

I have looked through the forums and documentation for the Zymkey4i, however I have not seen anything on if the Zymkey4i will work on a Raspberry Pi Zero.

Would the Zymkey4i have any issues on a Pi Zero?

Yes, Zymkey 4i will work with the PiZero.
Just beware that the Zymkey is longer than the PiZero is wide, so it overhangs a little.
Other than that it should work perfectly fine.

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Hi Both,
I’ve installed the Zymkey 4i on a Raspberry Pi Zero W. It works just fine.

One difficult bit, as mentioned above, the HDMI port gets blocked if you try to install directly to the headers - due to being longer than the pi is wide. To get around this, I soldered jumpers from the through-holes on the PI to the pin header that connects to the Zymkey .1 header adapter, then potted everything to hold it all together.

To Zymkey: A couple ideas for to make this easier:

  1. Can you plate the through-holes that are part of the header? That’s easier to solder to - and they are already there - just not plated for soldering.
    1a) Once you have that: Maybe sell a zymbit without that header-connector? Saves space and makes the whole thing more compact.
  2. Can you sell a little shim board for the zero? Something that rotates it and aligns it down the middle of the pi? That way it doesn’t cover the WiFi. I did this with my jumpers, but its ugly and had to be glued since its a potential failure point. (If you don’t I’ll probably need to commission this to reach scale.)

Otherwise this little board is a perfect balance for what I’m after. I can’t wait to get my hands on the 5.

DM me if you want pictures of how I did it.

Thanks!

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@mamacker - Awesome ! thanks for sharing. Yes, if you can please post a few images of your set up, so we can respond to your specific suggestions.

I had this exact same issue and resolved it in similar fashion as @mamacker

+1 on option #2

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@grundyoso you are a master technician! We can certainly help make is easier for you going forward by making an adapter for RPI Zero.

Do you use the Tamper Detect ? and if Yes do you like the connector use, or prefer and alternative ?

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@Phil_of_Zymbit I’m still in the early iterations of my design so haven’t gotten to adding Tamper Detect in yet. Right now I’m just trying to have some protection of the code base and keys running on the RPi0. I’m building these one by one at the moment so it’s a bit of a craft with the occasional mishaps. For instance, the jumper wires I used to extend the Zymkey connector run the risk of causing shorts on the PCB… as seen here:

So I added a thick gob of hot glue to secure the Zymkey onto my top PCB (Juicebox Zero) without risking shorts. The final assembly fits nicely into an enclosure I found on Mouser:

When I’ve gotten my design more robust I intend to add Tamper Detect, which I assume will be via the microUSB connector to some conductive trace adhered to the inside of the enclosure prior to it’s final assembly. Do you have some examples/pictures of how others have done this? It would need to be some process that’s irreversible for it to be effective so I’m sure there’s some good tips to doing that properly and reduce unintended failures in the field.

@grundyoso thanks for sharing more details. We can certainly help make the process easier for you, especially if you plan to use the tamper detect with some kind of mesh/wire.
If you can share the exact enclosure you are using (send us a private message if you prefer to support@zymbit.com)… then we can take a look at what we have that will work.
Thx, Phil

@Phil_of_Zymbit I’m using this enclosure at the moment:

Perfect, thanks for sharing. We’ll take a look at get back to you early next week.

(Coincidently, NewAgeEnclosure is just down the road from us in San Luis Obispo!)

@grundyoso This part looks much bigger (4 x 8 x 1.5 inches) than the one in the drawing you sent over. Am I correct ?

I put the wrong link originally and then corrected it… i believe the correct one is reflected on my updated post but here it is again just in case:

it measures 3.25"x2"x1"

Looks good this time. Thanks

Any chance those shims are around the corner? I have to build 5 more now… and would love to use a sleeker method. :slight_smile:

shims? - do you mean PiZero to ZYmkey, or the perimeter adapter ?

PiZero to zymkey.

That’s the one one that resulted in ugly soldering. :slight_smile:

-Matt

Looks like the design was revised to accomodate some additional customer feedback. Its should be going to fab early next week, ETA for first boards Oct 21.

Not sure if that timing works for you ? either way i can get you CAD/Mechanicals when its pushed to FAB.

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@grundyoso @mamacker
We took on board your need for a PiZero adapter and came up with the following !
Would love to hear you feedback before we go to fab with this. Thanks for your inputs.

Key Features

  • Rotates Zymkey 4 by ninety degrees
  • Adds extended battery socket for CR2032 (delivering nominally 5-7 years operation)
  • Easy access to perimeter detect features
  • Blocks SDcard by adding perim adapter (type4)
  • Adds FPC (flexible printed circuit) cable, or customer FPC for wrap around security mesh
  • All active components face inwards, making it easier to wrap with a mesh and /or pot

Overview

Fully Assembled with Perim Adapter

Exploded View 1 - perim removed

Exploded View 2 - pi zero removed

Exploded View 3 - zymkey 4 removed

Schematic

This is awesome!!! Let me know when I can pre-order! I’d love to see the flex shield too. If it’s possible, can the flex shield leave the ports accessible? (And avoid blocking the wifi as much as possible.)

This looks like a far better solution than my ugly soldering. It also looks like I can solder to the perimeter detect breakout pads - which is great.

hell yeah, this is amazing work!! I love the sdcard-blocking daughter board. :slight_smile: the assembly also leaves space for the juicebox zero to mount on the top side along with a battery… I’ll need to check my enclosure clearances but seems like I can make it fit. When can we get some pre-orders??

thanks for the quick turn around hustle… this looks very promising