It is simple electronic dice powered by chinse copy of arduino nano and 9V battery. The roll of dice is triggered by one poushbutton on the top - rolls random number with random length animation and buzzer beeps when animation finishes. Power switch, and mute/unmute switch can be found on the side. Source code for this thing can be found in Thing files.

https://www.youtube.com/watch?v=c4zydXXOAcM

Printed with PLA, 0.2mm layer and 0.3mm nozzle. 30% infill should be enough.