Here’s a quick test video of my Arduino Nerf sentry gun in action. When my hand gets closer to the PING sensor than my initial value (in this case, very close), the gun stops sweeping and starts firing.

I didn’t have ammo in the first few belt casings, so I avoided getting shot. This won’t be the case when I demo it at Maker Faire this weekend.

In the Maker Shed:


PING))) sensor


7-Segment Shield

John Edgar Park

John Edgar Park

John Edgar Park likes to make things and tell people about it. He works at Disney Research and writes for Make and Boing Boing. He is training for American Ninja Warrior. You can find him at and twitter @johnedgarpark — if you like that sort of thing.

  • George C. Bragg

    Um, is there a “how-to”? The link in the video text seems to just lead back here…