Integration with Home Assistant

I'm not sure if you spotted it, but I did post some code on https://forum.espruino.com/conversations/382301/#comment16798335 - sorry I missed this post when you made it last year though!

I see from the documentation of BThome that different button actions are also supported. Would it be possible to create an app with a "screen button", or even use the side button on Bangle.js 2, to be integrated in an HomeAssistant automation?

Do you have a link? I'm sure we could do something like that, yes. We now even have an app that will send temperature.

There is already a home assistant app which uses Gadgetbridge and the home assistant Android app too.

this bthome integration looks awesome, is there a good way to send custom data?

There is count I guess: https://bthome.io/format/

But if you have a specific request, maybe contact the developers. It seems like an evolving standard :)