This is one of those tricky ones.
Keyboards is generally the traditional keyboards - a matrix of switches connected to a controller, usually in a QWERTY or similar layout.
Input devices, as the forum description says, is for touch pads, trackballs, joysticks etc.
What you are developing, although used as a keyboard, is not something that people would immediately recognise as a keyboard. OTOH it IS a keyboard, but a new design.
It might also fall into the "other geeky stuff" too - that covers mobile phones and similar devices.
I'd say leave it where it is for now, and if you don't get a response in another couple of days (bearing in mind that a lot of people might be away, what with being Easter), and if you don't get many responses, perhaps ask one of the mods if they could move it to a more appropriate area.