keytee -- Controller breakout board for small keyboards

[trebb]

Ordering PCBs for a recent project of mine, I didn't quite like how shipping cost exceeded the actual product value, so I tried to shift the balance in favour of the latter with something useful: a keyboard controller that doesn't increase the size of your hand-wired keyboard in any way.

Keytee is based on the ATMEGA32U2. With its 20 usable I/O pins, it can drive keyboards with up to 100 keys. I tested it with TMK. The bootloader I use belongs to the LUFA project which has been incorporated into TMK.



PCB, back side. Thickness is 0.6 mm.


PCB, component side. I used solder paste and hot air from the cheapest rework station I could find. Overall height, including controller, is 1.5 mm.


Intended use. If your keyboard has at least five keys, then keytee won't add any bulk.


Programmer, made of old computer parts with liberal amounts of hot glue. The spring contacts come from a RAM socket.


I have a couple of spare PCBs I'm willing to give away if someone is interested. Weight of a single PCB is 0.3 grams, so shipping cost should be affordable, I suppose.

The whole project is on Github under an open-source licence.

[Matt_]

Impressive. How would you go about installing this in a keyboard? Solder wires to all pads, install the controller and then connect the wires where they should go?

Also, do you sell the PCB naked or with all components soldered?

[trebb]

How would you go about installing this in a keyboard? Solder wires to all pads, install the controller and then connect the wires where they should go?

Exactly, using thin stranded wire.

Also, do you sell the PCB naked or with all components soldered?

Naked. Soldering for someone else could only be an exception.

[duynguyenle]

Sorry for the noob question, but where does the USB port go? Do you need to get an additional breakout board with the USB connector?

[Matt_]

How would you go about installing this in a keyboard? Solder wires to all pads, install the controller and then connect the wires where they should go?

Exactly, using thin stranded wire.

Also, do you sell the PCB naked or with all components soldered?

Naked. Soldering for someone else could only be an exception.

I see, thanks.

[Ced67]

Sorry for the noob question, but where does the USB port go? Do you need to get an additional breakout board with the USB connector?

The usb signals are noted GND/+5V/D+/D-. I believe you can either directly solder a usb cable or one side of extension cord, like that one: https://www.amazon.com/YCS-Basics-Femal ... B00IFG9FDO

[xszy]

This is so cool! I would love to try one of these out of the jd40 handwire I'm planning on doing once I get more solder. If I could use this instead of a teensy that would make the case so much smaller and the board overall much slimmer! Great concept, I love the premise of this project!

[rominronin]

Looks good. I'd like one if you still have one going.

[trebb]

I'd like one if you still have one going.

PM me an address and I'll send you one or two in a letter.

[need]

If a 100 keys keyboard controller could be made this small, I wonder why every keyboards out there has bigass controllers?

[Ray]

With three lock-lights you would be down to a max of 72 keys.
Plus it needs hand-soldering, since there are no connectors possible to the pads.

[xszy]

Do you happen to have any more available? I would love to pick one up.

[trebb]

Do you happen to have any more available? I would love to pick one up.

I do. Just PM me your address.

[NuttyOx]

Awesome build! I would like one as well if you dont mind PMing the cost and we can go from there

[trebb]

Awesome build! I would like one as well if you dont mind PMing the cost and we can go from there

No cost as long as demand remains as modest as it is now.

[hargon]

Really nice, I like the design!

[Sythe]

Hi, really like the design and am interested in getting hold of 1 if you still have any left.
Sent you a PM as well.

[rominronin]

I'd like one if you still have one going.

PM me an address and I'll send you one or two in a letter.

Sent a message.

[rominronin]

Just received mine, thanks @trebb.

Can we find someone to turn this into a group buy? If we find a manufacturer who can produce the board with all the components in place, I'd be interested in perhaps dozens (for the right price).

[trebb]

Can we find someone to turn this into a group buy?

I'd appreciate and be willing to help if someone wanted to do this.

[tuxlovesyou]

MUST HAVE!!

[Sythe]

Just received my Keetee pcbs. Thanks so much for sending them.
I will update once I finish my project with them.

[CountZero]

I tried uploading pcb.kicad_pcb to osh park and got "we can't build anything with that many layers." Tried opening the project up in kicad and when I tried to look at the circuit board I got the following error:



Could anyone tell me if this is something I need to fix on my end ? Or is it a problem with the files up on github ?

[Sythe]

Just about to order parts and I just wanted to make sure.
What were the package sizes used for resistors/capacitors/crystal?

[Ratfink]

I tried uploading pcb.kicad_pcb to osh park and got "we can't build anything with that many layers." Tried opening the project up in kicad and when I tried to look at the circuit board I got the following error:

[snip]

Could anyone tell me if this is something I need to fix on my end ? Or is it a problem with the files up on github ?

I get the same error on Linux with KiCad 4.0.5.

[trebb]

What were the package sizes used for resistors/capacitors/crystal?

You need size 0402 capacitors and resistors, and a crystal like this:
http://www.produktinfo.conrad.com/daten ... HZ_SMD.pdf

[Sythe]

Awesome, thanks.

For some reason I thought they looked smaller than 0402, but thats good to know.
I have access to a lot of 0402 parts.

[trebb]

Could anyone tell me if this is something I need to fix on my end ? Or is it a problem with the files up on github ?

I get the same error on Linux with KiCad 4.0.5.

Can confirm for KiCad 4.0.2 on Ubuntu. I'm using PC-BSD/FreeBSD where the KiCad version info looks like "r6904-product"; not sure how these relate.

Generated Gerber files and PDFs can be found at https://trebb.github.io/keytee/.

[CountZero]

Could anyone tell me if this is something I need to fix on my end ? Or is it a problem with the files up on github ?

I get the same error on Linux with KiCad 4.0.5.

Can confirm for KiCad 4.0.2 on Ubuntu. I'm using PC-BSD/FreeBSD where the KiCad version info looks like "r6904-product"; not sure how these relate.

Generated Gerber files and PDFs can be found at https://trebb.github.io/keytee/.

Thanks! The gerbers from your link worked perfectly. For anyone interested in building one, I ordered six boards from OSH Park and it cost me all of 5.70$ shipping included (I'm located in the US, which may effect that). I'll have to order components and whatnot but that seems like a very reasonable price for PCBs. I love the design, and am looking forward to doing hand wired projects without worrying about excessively thick cases or finding somewhere to jam a teensy.

[trebb]

For anyone interested in building one, I ordered six boards from OSH Park and it cost me all of 5.70$ shipping included (I'm located in the US, which may effect that). I'll have to order components and whatnot but that seems like a very reasonable price for PCBs. I love the design, and am looking forward to doing hand wired projects without worrying about excessively thick cases or finding somewhere to jam a teensy.

So you should be able to make single-digit batches with components from reputable suppliers for less than 5 [$€£] apiece, ignoring labour and tools. The 1.6 mm thickness OSH Park seems to do exclusively(?) may look a bit overweight, though.

One can still get a couple of free PCBs from me; these would be 0.6 mm thick.