Hi there!

It’s currently just the Q10. The other keyboards have different connectors and different keyboard matrix configurations. It wouldn’t be too hard to adapt it to another keyboard, except that you’d need to know what the target keyboard connector is called. I tried to figure that out for the Key2 and at least when I was at the research phase (~2 years ago) I couldn’t find any info online about that.

After the connector is known, the rest isn’t too hard. The next step would be to make a breakout port, so you can figure out the keyboard matrix layout. Here you connect each pin from the matrix to an Arduino and just trace which two pins get shorted when you press which button.

Then you just feed that info into the Arduino sketch that is running on the final device, adjust the KiCAD designs for the new connector and that’s basically it.

Except if you want to support higher-level features like capacitative touch on the keyboard. That would be a bit more difficult.

I don’t I have the time to do all that work, but if you want to, feel free to do so!

Regarding the correct measurements: The easiest thing would be if you find an STL or something of your phone. There are lots of these for many phones available. You can then just dump that into the script (there is an option of using an STL shape as a “negative mold”. You then go to GSMarena or something like that and fetch your phone’s dimensions from there.

Be aware that any modifications to your phone (e.g. screen protectors) must be accounted for. To do so, get some cheap digital calipers (I got mine from Aliexpress for €4 including shipping, but Amazon also has them for ~€10). They allow you to perfectly measure the dimensions.

The most difficult part is the corner radius, which you have to pretty much guess.

If you have a 3D printer, you can just try out a few different settings and figure out what fits best. It should be a tight fit without wiggle room, but it should also slide on and off with little resistance.

Pass-through charging would be possible, but I determined that if I put everything in that I want, the project would never be finished^^

I also considered adding a headphone jack, but that was also cut.

Passing through more than charging gets complicated fast. That would require a fitting hub. USB2 would be possible, USB3 would be difficult, stuff like display port would be really hard.

Also, afaik, a single USB port cannot be in host and device mode at the same time, so I believe it would be impossible to have the keyboard attached and connect the phone to a PC at the same time.

In the end I settled for a quickly detachable design to avoid all that added complexity.

Another option would be to use a phone with wireless charging and wireless connectivity.

F for firmware?

FOSD could be used for design files.

Minimum order quantity for most of the device is 2, and it costs ~€40-50 per piece if you make 2 of them. If you make 10, this drops to ~€20-30 per piece. If you want to, I can link you up with some people that might be willing to pre-pay, so that you can get the funding to make an initial batch.

From what people told me, they’d be happy to pay €50-150 per piece, with most people being at €70-100.

Required skills would be soldering (same pitch as TQFN44) and 3D printing (PETG) for making them, and Blender or OpenSCAD for adapting the design files to other devices than the FP4.

Yeah, you are right. On the other hand, all the software on there is also FOSS and if you are very liberal with the term “software”, design files could maybe also be construed as software.

Tbh, though, I’ve never seen anyone use the term FOSH.

Looks like you got your energy back ;)

Looks like you need a better nuclear powerplant setup.

Both where fighting against fictional problems.