Tiny Pack v3b

This 3D printed case combines common parts into a small programmable controller with battery and charger, allowing access to all pins without opening the package. The total cost of this setup is less than $5, though you may have to buy multiple pieces of some components to reach that price.

The Bill of Materials includes:

• DigiSpark (or clone) ATtiny85, Arduino compatible controller with USB example link
• LiPo charger with TP4056 (battery pass-through, USB 5V input) example link
• 300mAh LiPo power cell. example link
• Two tall microswitches example link
• 6-pin right-angle female headers example link
• 3-pin male headers (Included with Digispark)

The resulting package is a small programmable computer with two switches and easy access to GPIO (fem Dupont headers), power (3-pin male headers), and USB for programming and charging. The internal connections from charger to battery and from battery to Digispark should be soldered with fine gauge wire.

The top and bottom halves can be printed in any PLA. 0.2mm layers are sufficient. I've included a complete STL with all the components to aid development or modifications.

This is a work in progress. Note the 300mAh LiPo usually comes with a Syma (JST-DS)connector. You will have to cut off the battery connector and solder directly, possibly replacing the whole wire since there isn't room for the wire+connector. It's a very tight fit and will need some tuning. The non-pass-through version of the TP4056 charger is shown, which is not ideal. Also, the digispark will be getting 4V, not 5V, from the LiPo without a regulator, which works more reliably in 8MHz mode. Switching controller speed requires re-flashing the bootloader on Digispark.