For now all i have is the ideia, a dream and some initial draws.

I initially started to thinking which microcontroller i will use for this project, and some easy ideias come to my mind, like the; RP2040, Atmega32u and STM32F103, all with USB interface Build-in and a vast community examples of how to use them like a keyboard, but after some research i found none of them has capacitive touch functionality, which is not exactly a problem, cause this functionality can be easily implemented by software, but with little bit of more research i discover the CH32V303, which accordingly to his datasheet have built-in USB2.0 and 16 channels of capacitive touch; with this i could multiplexing 12x4 touch pins and get a 48 keys, which is more than enough to consider this a 40% keyboard. The chip is very cheap (:D) and just need a few passive components to work well. So the CH32V303 was the first choice for this project, i hope the software development doesn't make me regret.

Other thing that i wanna for this project is a PCB usb-c connector where i get the ideia from here, this make the project cheaper and more easy to give away it to someone else, which is the propose of a business card, but i will talk more about costs later.

Here's the first drawings: