Pretty much anything electronics related is on-topic as far as I'm concerned - although I probably won't be able to help too much with non-Espruino stuff ;) There's the Interfacing forum for connecting stuff up to Espruino/microcontrollers, but I'm open to adding other ones if you think I've missed something out.
Espruino is a JavaScript interpreter for low-power Microcontrollers. This site is both a support community for Espruino and a place to share what you are working on.
Pretty much anything electronics related is on-topic as far as I'm concerned - although I probably won't be able to help too much with non-Espruino stuff ;) There's the Interfacing forum for connecting stuff up to Espruino/microcontrollers, but I'm open to adding other ones if you think I've missed something out.