Dummy AA and AAA batteries

thingiverse

When you're tired of changing batteries and want to use a USB power source instead, you can do some electronics modification or you can use these dummy batteries instead of modifying the battery powered light/game/toy ... Three alkaline type batteries in series supply 4.5V, just right for a 5V USB power supply. Solder the USB black and red wires (from an old wired mouse, dollar or thrift shop) to the cathode and anode of two dummy batteries and insert those instead. This design has holes in both ends for the wires and to make terminals (I used some solder wick for the contacts). You may also want to use the dummy battery as a straight through short circuit. The designs should print nicely without support if you lay them with the long flat side on the bed. All overhangs are 45° or less. They won't bend with age because they have longitudinal support in the form of a cross through the length. This also leaves space for the wires to run. Files are 3mf for best accuracy and cura lays the origin at the origin so you have to move the model to the middle of the bed, or wherever you like to print, and above the bed. Also turn it 45°. STL's are also there.