Creating a 3D-printed, Arduino-powered rubber band sentry gun

Thanks to this Maker’s project, you’ll never have to fling rubber bands with your fingers again.

If you’ve ever flung a rubber band into your sibling’s back or launched one across a classroom, then you’re sure to love this 3D-printed project from Kevin Thomas. Up until now, there’s only a been a handful of ways to fire one: the index finger, the thumb, the combination of the two, and then of course, the tip of a pencil. That may all change thanks to what the 20-year-old Maker calls the Rubber Band Sentry Gun


Traditionally speaking, a sentry gun is a firearm that automatically aims and shoots at targets that it detects via sensors. In this case, Thomas used this model as the foundation for a fully-functional rubber band version. After stumbling upon a design on Thingiverse for an Automatic Rubber Band Blaster, the Maker was inspired to devise a mechanism that would be entirely automated.

In order to accomplish this, he employed an Arduino Mega (ATmega2560) as the brains of the gadget along with a pair of servo motors, a micro servo 180° for its tilt, another normally sized one for the pan, and a 360° servo motor to actually fire the band. The project, which took about three days to complete, is capable of shooting 24 rubber bands in succession, though he tells that it can easily be adapted with a larger barrel to fire up to 30.


Thomas used a software package created by Project Sentry Gun in order to control his device, enabling it to find and shoot any moving target. Meaning, no more having to prep your fingers, locate your sibling or friend, and then hope to launch it further enough to hit them! As for the 3D printing portion of the project, the Maker designed the unit with Cubify Invent and printed it with his AVR powered bq Witbox.

Okay, now you have to see this thing in action! Want to make one yourself? Head over to its Thingiverse page to get started.

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