[IC] Piggyback, the keyboard-centric microcontroller board.

[KiserDesigns]

Piggyback

Piggyback is an RP2040-based controller board with three built-in 5-pin MX switch footprints. Similar to the Postage Board Mini, but now with the power of the RP2040, castellated edges, and a removeable USB port.



When the USB port is removed, it can be inserted co-planar with a sister PCB, making it trivial to design an "integrated" PCB (as opposed to a PCB that uses a pro-micro), without having to place and route the complicated components of the MCU.



A Kicad symbol and fooptrint make it easy to implement into new designs, and leave only diodes to be assembled on the sister PCB if the board uses the ezMate uDB connector.




The USB data and power lines broken out to the removable USB-C port, an ezMate connector for USB daughterboards, and to the castellated edges where they can be routed to the sister PCB's own USB implementation.

All 30 of the RP2040's I/O is broken out to the edge connector, with 4 of them being used as the columns and row of the 3 built-in switches.

Prototypes have be produced, and are confirmed fully functional.



I would love to hear your feedback, and know what you would like to see changed. The idea is to have these available to folks wanting to do cheap on-off or low-quantity PCB runs, or for hand-wiring a board without adding the thickness or size of a pro-micro.

I am also looking for potential interested international vendors.

[NoPunIn10Did]

From the integrated design side, it seems like it would be most useful as a library rather than to buy them already-manufactured. Do you have plans to license the design and/or make it open source?

[KiserDesigns]

That is a really good point. Are you thinking that this could be used a design basis for integrated boards, like a Kicad template?

[NoPunIn10Did]

That is a really good point. Are you thinking that this could be used a design basis for integrated boards, like a Kicad template?

That would be one possibility, yes.

[xjack312]

This is pretty cool, can definitely see it becoming popular compared to promicros. Well done!

[aicyborg]

Since this project's in the name of making PCBs easier and more accessible, could this be adapted for hotswap or are the components too close together?

[KiserDesigns]

Making a hotswap version would be difficult, but I am looking into it. It would definitely be the next logical step forward.
In the meantime, using Mill-Max sockets would be the next best thing to having Kailh sockets.

[Farhandsome]

This is super cool! Love to see the rapid implementation of the Molex EZMate and RP2040 lately and this makes it even more accessible.

[Jiunix]

This is great! I'd been waiting for something similar to the postage board mini to be released again for use with handwriting. The only (useless) suggestion I have is to make the PCBs purple 

[VXQN]

Fantastic idea. I've been thinking of something like this for a while, but your implementation is much more elegant than what I was turning around in my head.

I do agree with the assertion that the nature of the project does scream "open-source", so I hope you'll consider that.

[hunos]

Definitely interested. Would you consider Alps support as well?