Robot battle arena prototype.
As popularized by numerous YouTube channels, battle bot competitions with everything from legos to RC creations are spreading like wildfire. Here is arduino C code that latches a servo trap door with the use of a momentary pushbutton while a servo hammer oscillates.
The .STL 3D printer files are for a perimeter wall that you can scale to your bots, and a hammer which has worked well on a metal gear 9 gram hobby servo.