Viz.:
Since a lot of stuff depends on 3v logic/power nowadays, I rigged this up.
It’s a CR2032 button-cell holder soldered to a couple of flat-toothed alligator clips.
I found these at a local component shop. The flat “lips” of these clips make them perfect for clamping onto edge-pads like a micro:bit or one of Adafruit’s little dev boards.
They’ve also been useful a few times with Charlie and other Pi related things.