Raspberry Pi Sentry Turret Is The Enemy Of All Mankind

War, huh, what is it good for? Absolutely nothing, except as an excuse to build a Raspberry Pi powered sentry turret that will track and fire upon your enemies. That’s what [Matt Desmaris] decided to do, and he has released the full details of his build.

It lacks the polished elegance of most military hardware, but what do you expect of a quick and dirty hack? It’s not shiny or ominous, but it has that killer motion-tracking feature. [Matt] is using OpenCV to detect movement from a USB webcam, two servos to pan and tilt the camera and gun and a small relay to pull the trigger. Manual control over the Interwebs is also available.

We’ve seen lots of similar builds using weaponry such as rubber bands and Nerf guns, but this one is a great start if you are interested in seeing how you can tie together tools like OpenCV and servos to create a camera that actively tracks movement.

Arduino Powered Rubber Band Sentry Turret Is Not a Lie

You know that guy in the next cube is sneaking in when you are away and swiping packs of astronaut ice cream out of your desk. Thanks to [Kevin Thomas], if you have an Arduino and a 3D printer, you can build a rubber band sentry gun to protect your geeky comestibles. You’ll also need some metric hardware, an Arduino Uno, and a handful of servo motors.

The video shows [Kevin] manually aiming the gun, but the software can operate the gun autonomously, if you add some sensors to the hardware.  The build details are a bit sparse, but there is a bill of material and that, combined with the 3D printing files and the videos, should allow you to figure it out.

We couldn’t help but wish for a first person view (FPV) camera and control via a cell phone, so you could snipe at those ice cream thieves while hiding in the broom closet. On the other hand, if you got the gun working, adding the remote wouldn’t be hard at all. You probably have a WiFi FPV camera on your quadcopter that finally came out of that tree and there’s lots of ways to do the controls via Bluetooth or WiFi.

Not that you don’t have options. But here at Hackaday HQ, we have lots of rubber bands and not so many green pigs. If you’d rather shoot paintballs, be careful you don’t accidentally repaint the insides of your cube.

Continue reading “Arduino Powered Rubber Band Sentry Turret Is Not a Lie”

Angry Birds Sentry Gun has Pigs Flying

[Farlei Heinen] has a C programming class at school. Not wanting to do another boring cookie-cutter project out of the textbook, he decided to do something different — he’s built an Arduino controlled sentry gun!

It consists of two parts: The sentry gun itself and a sonar detection tower which can tell if you’ve successfully knocked down the pigs or not. He’s using an Arduino Mega at the heart of the project, which controls the servos and reads information off of the sonar sensors.

The sentry gun uses two servo motors to control up and down, and left and right. The loading mechanism is manual, using elastic bands to launch the projectile. The firing mechanism however is a micro (9g) servo, which can release the elastic and shoot the projectile. The target is an Angry Birds toy play set made for kids.

It’s a pretty cool project, and [Farlei] has even released the source code for it if you’re interested in building your own — check it out in action, after the break!

Continue reading “Angry Birds Sentry Gun has Pigs Flying”

Open-Source Sentry Gun Plans Promise the Next Level of Office Warfare

We admit it, we were browsing Reddit when we found this beautifully hacked together Nerf Sentry turret. But are we ever glad we did — as it turns out, it is very similar to the totally awesome, open-source Project Sentry Gun.

We have actually covered a project that used that system before, but it looks like it has evolved a bit more since then. It’s just too cool not to share.

The system itself is quite simple and easy to build. You’re going to need three servo motors, an Arduino, a webcam, and assorted wires, nuts and bolts, etc etc. Grab a copy of the code, slap it all together, and you’re ready for business!

Just take a look at the following video of the Gladiator II Paintball Sentry Gun — we know you’re going to want to build one now.

Continue reading “Open-Source Sentry Gun Plans Promise the Next Level of Office Warfare”

Sentrifying a Nerf gun


[Brittliv] made the mistake of getting her friends into Nerf weaponry, and so began the race to mutually secured destruction via foam darts. She may have the upper hand in this war, because her Nerf Vulcan sentry gun is both incredibly powerful and is able to be operated autonomously with a webcam featuring a friend or foe identification system.

The azimuth and elevation mount for the gun is made out of plywood, with each axis controlled by a single servo attached to an Arduino. Of course a stock Nerf gun would be fairly boring, so [BrittLiv] increased both the voltage going to the gun’s motor and the strength of the gun by replacing a 2kg spring with a 5kg spring.

Targets are tracked with a webcam using Processing and a bit of code from Project Sentry Gun. One interesting feature is a friend or foe tracking system; if the gun sees someone wearing a t-shirt with the Instructables logo, the target is identified as a friend and is not brutally mowed down with plastic darts.

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Nerf Sentry Gun for the Apocalypse


If you’ve ever wanted to shoot someone with a Nerf gun, but just didn’t have the energy to get off the couch, this hack may be for you. It’s also a good way to ward off zombies if another apocalypse, Mayan or otherwise, is on the horizon.

Although the effects are very cool, as seen in the video after the break, the method for making this setup was quite simple. The requirements for this project were that the gun could not be permanently modified, and everything had to fire automatically. These restrictions may have contributed to the simplicity of the design as many of us would start breaking things before we had to.

Instead of some elaborate hack, the trigger was tied back in the firing position at all times. A relay was then used to interrupt the power supply to the mechanism allowing an Arduino equipped with an infrared sensor to automatically control the firing. The setup is explained after the break, but skip to around 1:55 if you’d rather just see the guns in action. Continue reading “Nerf Sentry Gun for the Apocalypse”

Automated Paintball Sentry

Reader, [Ben Godding], sends in the video for his senior design team’s automated paintball sentry. The frame is made of plasma cut aluminum. The paintball gun uses a custom hopper mounted remotely from the gun body. It has two webcams offering a 160 degree field of vision, and the image processing is done by a dual core pentium CPU booting windows xp off a compact flash card. The computer interfaces with the 1/4scale RC servos using a PIC24. The paintball sentry can either be configured via a computer GUI when a monitor is available or a baclkit keypad and 4×20 charachter display in the field.

Related: [Jared Bouck]’s paintball gun turret