Raspberry Pi Zero Compatibility

@grundyoso @mamacker

Thanks for the positive feedback ! We are wrapping up a few manufacturing items, and expect to get in our webstore by Friday for pre-order, with deliveries in about 3 weeks.

@mamacker - the challenge with a complete wrap around flexshield is that it will likely interfere with the WiFi, especially if its a high density (small pitch) design - it makes a pretty good Faraday cage. So we have some finessing experimenting to do here to figure out what the right balance is.
As a start we suggest working with a standard FPC cable like one of these, then wrap it where you need it most:

> molex, 1mm pitch, 7 conductors, 300 mm length

> parlex, 1mm pitch, 7 conductors, 18 inch length

Yup. I completely understand the faraday cage problem.

Thanks for the recommendation on the cable. I’ll order when I can pre-order these boards. Thank your team for us - this is great!

I’m going to modify my housing to account for the new board. Any idea what the expected height of the whole stack is? (Including the little end-blocking board.)

It looks like the other dimensions are the same as the pi-zero - though I should probably put in a little clearance for the FPC cable.

Very well designed. Everything is well thought out here.

Very nice. I will definitely be ordering one.

@grundyoso @mamacker @mlts22 @josephmarsden

PiZero hat for Zymkey is now available for pre-order from our store, first shipments expected by Oct 30.

Special Offer - For the first 25 orders received, we’ll be throwing in a new Zymkey 4 too !
This offer now fully subscribed @ 2019.11.03 !

Thanks for all your inputs !

Buy Now >

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@grundyoso @mamacker @mlts22 @josephmarsden
Your boards arrived today - there in the lab for testing.
We hope to be sending out to you early next week.

Awesome! Can’t wait!

stellar… they look great

Just got my Pi Zero Hat in the mail today, can’t wait to try it out!
How tall are your Pi headers? Mine seems to be a little short and the Zymkey connector pins are touching the board when I try to put it on. Small thing but should be easy to fix.

@josephmarsden -

We don’t fit a connect because everyone has a different application need. For the most compact assembly use a connector with a body part which is 8.5mm depth. Greater depth also works.
We’ll post some mechanical drawing soon

Any of the following header connectors should work - these are UK supplier links

https://shop.pimoroni.com/products/booster-headert

https://uk.farnell.com/multicomp/2214s-40sg-85/connector-rcpt-40pos-2-54mm/dp/2847248

@Phil_of_Zymbit got my boards in today and played around with some assemblies since I need to accommodate the Juicebox board in my solution… my tl;dr: it’s a good first iteration, but there’s room for improvement. in the first config (most compact), zymbit board mounts could be longer to simplify assembly while avoiding shorts. in second config, the zymbit connectors collide with the juicebox tallest parts creating a lot of wasted space.

@grundyoso
Thanks for the feedback.

Standoff Height
To set the minimum standoff distance, without causing a short hazard, use a 7mm x M2.5 x 0.45 screw in standoffs (yes we can put them in the kit going forward, if that makes sense for customers).

Available here > https://www.digikey.com/product-detail/en/raf-electronic-hardware/M2102-2545-AL/1772-1944-ND/7681355

@Phil_of_Zymbit I got some standoffs and played around with fitting the final assembly in the NewAge enclosures I have. Save for Dremel-ing down the enclosure walls, there’s nothing I could do to get things to fit right. I even used 6mm standoff instead of 7mm you suggested. The stack up with the Juicebox is still about 1/8" (1/8th of inch) too tall. Judging from the layout of the Zymbit and Juicebox boards the only opportunity to reduce stack height would be to move the Juicebox connectors to the opposite end of their board. That way achieve the most stack density without losing the protection of the perimeter adapter on the sdcard. This will also allow for the charge connector on the Juicebox to not be so recessed from the enclosure walls which is a pain. I will contact the Juiceboox and refer to this post to see what they say.

Just as an FYI - I’ve successfully booted a raspberry pi zero - using cryptfs on the SD card - and using this add-on board.

This is great. Thank you all for the quick turn! Now I just need to update my housing a little, and figure out the perimeter stuffs.

@Phil_of_Zymbit Since installing the HAT the Zymkey has gone into some state where it flashes quickly 10 times, pauses, then slowly 8 times, and zkgrifs shows “no zymkeys installed” - what does this mean?

Zymkey is in development mode (I have not cut the lock tab) and no perimeter actions set.

@josephmarsden - can you give us some context.

  • What linux distro are you using ?
  • When you initially got you Zymkey running, was that with our without the Hat fitted ?
  • Have you had the Zymkey working, with the HAT fitted ?

Thx

Hi Phil. I’m using Raspbian 10 (buster).

Zymkey was originally working in a Pi 3B and bound to it fine - was under the impression it would “re-bind” when moving it to the Zero, as it’s in development mode. I don’t believe I have had it working (bound) with the HAT as of yet.

If I connect it to the headers normally on the Pi Zero, it apperas to bind normally. Battery on the HAT is the right way around (face down) and there is no battery in the Zymkey.

Sometimes the Zymkey will not even flash when it’s connected to the HAT, it will just stay dark for several hours and then flash in the 10-quick, 8-slow pattern I’ve observed.

If its working without the hat (direct to the Pi), then it sounds like an electrical/connection issue.
Can you post a few pictures of your set up, in particular the headers from the Pi to the HAT.

Also, please check that the Zymkey is pushed all the way down onto the header.

HAT removed from Pi

Top view

Front view

Side view

Thanks for your help. It’s also worth noting that when the Zymkey is in the so-called dormant state I mentioned earlier, it won’t work immediately even if you connect it to the Pi header; it takes several hours to recover - I think this could possibly be related to the power rail tamper detection stuff, but my power supply is good, I’m using the official rpi power supply.

Thanks for the images. I don’t see any solder between your header connector, and the zymbit HAT. Did you just press fit them in ? In which case that is a high probability of being the source of your problems. The header connector needs to be soldered to the zymbit HAT to ensure all electrical signals are solid. (In practice, if you just solder the first ten pins (5x2), that will be sufficient.