Hacking the Trackball module to add another key (UHK-80)

Modding
1

I am interested in hacking up a trackball module to include an additional key, extending the keyboard to the left of the ‘n’, but otherwise leaving the positioning of the rest of the module as is. Is that a reasonable thing to do? Looks like I can maybe open up the module to add switch in the right place and 3d print a new cover allowing space to do that. Is it possible to wire a new switch into the module’s controller? Any other ideas for approaches?

-l

2

@mlac?

3

Interesting idea.

On a somewhat similar note, I have noticed room on the PCBs for some reed switches in the UHK60v1. Do they serve any purpose? Could I solder switches on them and use them in the firmware?

4

According to the design at GitHub - UltimateHackingKeyboard/trackball-electronics: The electronics files of the trackball module, there are plenty of spare GPIO pins, but some need to be exposed on the PCB, requiring a design change.

Alternatively, some of the nets in the Tag-Connect header can be repurposed for this purpose.

5

The unpopulated reed switch pads on the UHK 60 v1 PCB serve a development purpose: to easily reboot the MCU and trigger the bootloader without physical disassembly.

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6

So if I can get a GPIO pin or steal one from the Tag-Connect header, what firmware/software do I need to update so I can get it mapped? Is there a sw/fw architecture doc around somewhere? Is there a microcontroller on the trackball module that talks to one of the keyboard side’s microcontrollers?

7

No.

Yes.

See the firmware source code, namely the trackball and shared directories.

module.c key_vector.c, slave_protocol.c are relevant.

Please note that the amount of support we are willing to provide in this respect is limited.

8

Definitely trackball’s firmware.

With a bit of luck, that is all.

You will need to map the actions via macros.

Note that atm it is not possible to flash module firmware via uhk80.

9

So will I need some separate hardware to flash the module then?

10

Depends, I am working on uhk80 module flashing right now, so it should suffice to wait a couple of weeks.

Otherwise you will need a j-link probe.

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