M328 Case, USB powered

thingiverse

This modification of the transistor tester case was designed by alvaroalea. It's a smaller version that runs on USB power. To make it, you'll need a micro USB pinout board and a compact DC-DC boost converter - any type will do as long as it's small enough. I added a tiny capacitor to filter out the high-frequency noise generated by the DC-DC converter, making sure not to use an electrolytic cap.