[IC] Switch-mounted controller board (controller that solders to 2x switches)

[LifeIsOnTheWire]

Hi everyone.  I guess this isn't really an "IC", just wanted to show off something that I'm about to have manufactured, and get some feedback from you folks.  In simplest terms it is a controller board similar to the Teensy or Pro Micro boards that everyone uses for hand-wiring keyboard projects, however this one is specifically designed for keyboard hand-wire projects.

Pictures at the bottom V V V V

The concept behind this one is that it is soldered to 2x switches on your top row, and it is supported by soldering to the switch pins as you typically would with a PCB.  This controller board has a home!  That coveted 10mm thick sandwich-style keyboard is much easier now.

I made it because I feel the biggest problem with hand wire projects is that there is nowhere to easily stow your controller board.  Most people just leave them hanging in the case.  Some people glue them somewhere, and run a USB extension cable to the edge of their keyboard.  It is a rather troublesome factor for me.

I'm posting this to gain some feedback, and see if there are any thoughts or concerns that anyone wants to share, before I have them manufactured. 

This is a personal project, I'm prepared to buy a batch on my own.  I'm not doing this contingent on the success of a GB or anything.  If anyone happens to be interested in buying them, I will definitely take orders.

The board is about 99% done at this point.  I have several final touches left, some traces might be rerouted, I still need to clean up the solder mask a bit to cover a few exposed traces.  I will be ordering a batch of prototypes in a few days.

A few points/thoughts about the design:

- Atmega32u4 chip, full QMK compatability
- 25 IO pins available (including the Row0, Col0, and Col1 integrated into the 2 onboard switches)
- The 2 onboard switches have pinouts on the sides that allow you to continue wiring the remainder of Row0, Col0, and Col1
- I am in the process of changing the USB connector to a Type-C connector.
- The USB port is aligned to the USB cutout in most GH60/60% cases (between the 1st and 2nd switches on top row), it looks like the JD40 and others use this same position.
- This board is compatible with any layout as long as you have at least 2 switches on your top row with 1u spacing between them (I can't think of any layouts that don't offer this).
- The size of the board is made possible by rotating the 2x onboard switches 90 degrees, facing away from eachother, and the 2 switches below the board on the 2nd row are rotated 180 degrees.  See the picture below.
- The notch on the top left might need some resizing to actually clear some legs/supports if used in a Plate Sandwich-style keyboard.  I'm not super confident about it clearing some legs.
- Pinouts are arranged in a standard 26-pin (2x13) pin header layout (standard 2.54mm spacing, just like most PC motherboard ribbon cables, or like the Rasp Pi).  If you want to solder in a pin header, and use a ribbon cable to wire up your keyboard, this is ready for that.  However, most keyboards probably wouldn't have a enough room below a PCB for a ribbon cable connector (those ribbon connectors are like 14mm tall).  However, some angled high profile cases would have more than enough room.

The last thought I have about this is that one of my initial concerns was that some keycaps might not accomodate a 90 degree rotation (the cross-shape of the MX stem is not symmetrical), however I have never seen a keycap that does not have a symmetrical female-stem interface, they might exist, but I haven't seen them). 

Some people have also suggested that some keycaps might be excessively tight fitment if rotated.  I haven't found this to be the case with any of the switches and keycaps I have laying around.

Please let me know if you are familiar with any caps that would not work in this way, I am no keycap expert.

Layout image:  https://i.imgur.com/1Y5Paue.jpg

Example image of how the switches need to be rotated to accommodate the board:  https://i.imgur.com/zDCRIOe.png  I have over-exaggerated the overhang of the board that intrudes under the lower switches.  Its not nearly that much, I just wanted to emphasize the reason for the lower switches being rotated 180 degrees. 

Thanks for any constructive feedback you have

[Vulcan]

I cant open the picture, but from what i read, this is really groundbreaking

Sent from my SM-G935F using Tapatalk

[donut_sauce]

This is great!  I would definitely buy a couple. Any ideas on cost?

[LifeIsOnTheWire]

This is great!  I would definitely buy a couple. Any ideas on cost?

I'm not entirely sure yet.  I'll be ordering a batch myself, and based on volume, I might be able to sell them for about $20.  The cost could come down if I ordered more than planned.  I'm not sure I have the free time right now to manage a GB, but near the end of May I will have a bunch of free time, and I'll consider it then. 

For now I'm just going to order about 100x units myself, and I'll be happy to sell them as people are interested.

Just ordering about 5x prototypes in a few days (which I will hand-solder), and then I will order a big batch when I'm satisfied with the protos.

[LifeIsOnTheWire]

I cant open the picture, but from what i read, this is really groundbreaking

Sent from my SM-G935F using Tapatalk

I'll just post them here:

[Tom_Kazansky]

Do you have the dimensions for the board?

I'm using a controller board for my PCB too because I have not figured out how to use the Atmega32 directly.
Though the controller board that I'm using is a bit bulky so my PCB ended up bulky as well.

I'm looking for something smaller.

Your board seems to be what I need 
but:
- is there anyway I can add an alternate USB connector?

below is the image of the controller board that I'm using, it has pins for USB connector, I can connect my USB connector with them and this alternate USB connector will work as the on-board USB connector.

(sorry that the pic is blurry)

- I'm just stating my opinion: I don't like the on-board switches very much.

I guess it's too late to change the design now... so I will wait for your next board. 

[ErgoMacros]

Cool design. I like seeing how small we can go.

Here's another of my favorite small designs, Keytee:
    https://deskthority.net/workshop-f7/keytee-controller-breakout-board-for-small-keyboards-t15586.html

It does not do all that yours do, for example:
   * Atmega32u2 instead of your Atmega32u4 chip
   * TMK instead of QMK compatibility
   * meant to be hand-wired.
   * 20 instead of your 25 I/O pins

Still, if you haven't seen it before it is an interesting approach.

Good luck!

[LifeIsOnTheWire]

Cool design. I like seeing how small we can go.

Here's another of my favorite small designs, Keytee:
    https://deskthority.net/workshop-f7/keytee-controller-breakout-board-for-small-keyboards-t15586.html

It does not do all that yours do, for example:
   * Atmega32u2 instead of your Atmega32u4 chip
   * TMK instead of QMK compatibility
   * meant to be hand-wired.
   * 20 instead of your 25 I/O pins

Still, if you haven't seen it before it is an interesting approach.

Good luck!

Yes I like that Keytee idea.  Definitely outside-the-box thinking.   That's one of the things that inspired my idea. 

[LifeIsOnTheWire]

- is there anyway I can add an alternate USB connector?

I'll get exact dimensions when I get home.   

Why not use a Pro Micro with a USB extension cord?

[LifeIsOnTheWire]

Do you have the dimensions for the board?

Dimensions are 23 x 38mm

[Anakey]

Interesting project, I might get a couple if i decide to do handwire in the future. Personally i do not see a benefit of USBC at the moment, however what i would like to see is for the female usb connector to be through hole to avoid the connector coming off and potentially ripping the pads off the board with it.

[odd]

I would for sure buy a couple of those. I have a few handwire builds coming up and zI have not decided on a controller yet. I would love to be added to the list of people who would purchase if available