Simple to make 2s Li-Po charger, using just 2 components and a 3d printed shell.
Some life hacks for writing to cd's and tricks!
Using a cheap PI Zero W or similar
to build yourself, or to use my site.
The silent pocket Metronome with IEM connection (Or buzzer)
from the beat vocals and more
rft-mkd va-z-221 Tube info
A few PCBs made that can be used for anything you need!
Recommendation of Audio interfaces, Headphones, iem's, speakers