For GEMMA projects in particular, a slim battery holder with a built-in power switch is handy. Coin cells are fairly high capacity for the size; this pack can give you about 6V and 250mAh. However, it can’t provide tons of current for long periods of time, this pack can power a gemma plus three or four neopixels for a couple hours-- pack spares in case the party runs long.
This guide was first published on Aug 18, 2015. It was last updated on Aug 18, 2015.
This page (Coin cells) was last updated on Jan 19, 2021.