I love to take things apart and modify them. This automated Nerf Sentry Gun I made for Bay Area Maker Faire 2010 was one such project. There’s a lot of impressive engineering to appreciate and extend once you get inside and look around. Plus, this beast is big, loud, and fun.
I performed two major modifications to the Nerf gun: one, I adapted it to run from a DC power plug instead of batteries, and two, I wired the trigger to fire from an Arduino-controlled relay, unattended. (A transistor would make more sense, but I think this relay was all I had on hand!)
I scratch-built a turret from 80/20 aluminum and created a motorized mount controlled by an Adafruit Motor Shield and Arduino for the otherwise static foam dart blaster. I then added an ultrasonic distance sensor and wrote an Arduino sketch to detect subjects that get just a little too close…
That’s when it stops sweeping and unleashes a hail of rubber-tipped darts at its unlucky target!
For detailed build notes, check out the full write-up here.