I made this so I don't have to attach anything direct to the Circuit Playground. The CPE was a gift and I used this project to make the gift more interesting. The cutout version holds the 100mah battery in place and keeps the entire profile thinner. I used two washers for the magnet. I super glued the washers to the plastic back and used clear tape to keep the battery down.
Follow me on twitter @greybeard_3d.
Or check out the GreyBeard3D YouTube.
Or see the largest filament collection at