Built and programmed by Bob Rudolph, this awesome robotic sentry gun was designed to locate intruders, determine their path, and then fire at them. In other words, “the sentry gun picks up its target using a webcam attached to its tripod, which a laptop translates into movements for the servo motor controlled gun; once the target is in range, it’s blammo from gun pelting you with paintballs or AirSoft pellets.” Video after the break. This is what its creator has to say about the fourth version:

Version 4 is here, with improved accuracy, better vision processing, target path anticipation, a compact and portable turret, 750 round ammo capacity, and faster and more powerful software behind it.

[via Dvice]