I built the Robotic Gun for demonstrating how easy it is to make a basic autonomous weapon, and got shot by it a few times in live performances like this one in Zürich Switzerland.

Weaponised by a standard paintball gun mounted on a robotic turret, the system is using a machine vision software (open CV with processing) that allows the gun to track and shoot moving objects within its 180º range.

If you are interested in the topic of autonomous weapons, check this information page from the Future of Life Institute, and the related movie Slaughterbots: