Midi controller that snaps on to my trumpet. Made from a tiny drone remote control with a replaced "brain" and new housing.
https://i.imgur.com/oYFOBNv.jpeg
And an app that records audio retroactively. Wanted to have recorded the last 2 minutes? just tell it "-2m". It has a ring buffer that buffers the last 2h, but also forgets all the time. (at least that was the plan, but audio streams were so much more difficult so I just dumped a full day of audio and timestamps and cut it later. That makes it much more "eavesdropping" again though which I wanted to avoid with the auto delete though....)