I find that having a way to check the battery and connection status is very useful with wireless devices. Traditionally, the way to do this is through the addition of a display. However I always thought displays were a bit overkill for that and once I started using Xiao BLE controllers I noticed that they have an RGB LED built onto the controller itself that can be programmed.

So I wrote a small tool to indicate the battery and BT profile status that uses that LED, and I thought I’d share more broadly in case it is useful to others. It’s pretty easy to add to your ZMK build as documented in the README as it is a ZMK module.

While it supports Seeeduino Xiao BLE out of the box, it’s also easy to add support for it if you have a custom keyboard that has three dumb LEDs for RGB colors.