If anyone is really looking for a single-key macropad... the Seeeduino Xiao is a small microcontroller development board which would suit the purpose. e.g. http

If anyone is really looking for a single-key macropad... the Seeeduino Xiao is a small microcontroller development board which would suit the purpose. e.g. https://www.40percent.club/2020/08/wonky.html https://www.40percent.club/2020/08/wonky.html