If you’ve played Team Fortress or its sequel TF2, you’ve certainly run into a sentry gun. This unit can be set up by an engineer character to guard various positions, and looks like something that could make an amazing prop.

YouTuber “henry3136” apparently agrees, and spent an estimated 400-500 hours building and programming his own out of cardboard, plastic bottles, and a few 3D-printed bits.

His Arduino-controlled gun pans back and forth using a servo and “fires” whenever it senses a target with its ultrasonic sensor. An Adafruit Audio FX Sound Board helps produce some fun effects, while the barrel moves in and out to scare off the bad guys.

You can see it in action below!