Robotic sentry gun

sentry gun

Reader [aaron rasmussen] and his brother Ezra built this awesome robotic sentry gun. The gun is an airsoft replica of an FN P90 and fires 6mm BBs. Pan and tilt are controlled by two hobby servos using a simple controller. Aaron wrote custom software to watch the usb webcam and track targets. There is a video on the site of it being tested

Imagination Not Necessary With This Helicarrier Bed

We think we have another dad-of-the-year award to give out. When [Andy’s] five-year-old son won a Raspberry Pi 2 and needed a new bed, they decided to build the ultimate bed. It’s loosely based on the Helicarrier from S.H.I.E.L.D. and it’s packed with so much tech, you barely need to imagine anything to have fun with it.

It looks pretty simple from the outside, until you realize that the detailed little hatch on the side is actually a keypad secure entry automatic sliding door. Controlled by the Raspberry Pi, recordings of [JARVIS’] voice speak to you as you enter the belly of the ship, er, bed.

imag1813Inside are glowing display cases featuring some of his son’s favorite Marvel superhero’s equipment — ready for use. But what’s really cool is the command console.

The terminal is expertly crafted to look like something out of the movies, and with the Raspberry Pi 2, his son can play with it and fight off the bad guys. There’s even a sentry turret with camera on the outside, controlled from inside the bed.

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SPARC: A Voice Controlled Robot Sings Sweetly in DTMF

One of the recurring themes of science fiction is the robot. From such icons as C-3PO and R2D2 in Star Wars to WALL-E and Eve, robots have always had a certain appeal. Inexpensive microcontrollers like the Arduino have opened up the world of robotics to more people. [JohnFin] has done just this. By linking two Arduinos as the brain, he has created a voice controlled robot he calls S.P.A.R.C. (Sentry/Project Assistant/Robot Companion).

It began when he received a robotic arm for Christmas and was disappointed by it. Instead of simply building a better arm, he got “carried away” and built an entire robot instead. The entire project took three months, most of which he spent learning programming.

SPARC has three sonar sensors for detecting obstacles and movement, an arm and a couple of interchangeable hands for holding objects, and an EasyVR Arduino Shield for the voice control. The robot’s “eyes” are an LED ‘KITT’ scanner and an AN6884 VU meter chip that flashes the “eyes” when the robot speaks. It carries an onboard smartphone to look up weather, play music from the phone’s SD card, and GPS functions.

SPARC can respond to a range of commands and games including “follow me” and “singing.” [JohnFin] has also added a “sequencer” function to record and playback a series of commands. A video of this feature can be found after the break.

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Upgraded Nerf Gun Keeps Track of your Ammo

[Paul] and his buddy [Jonathan] recently had a zombie themed Larp event to go to, so in the spirit of making the experience more realistic, they decided to upgrade their Nerf N-Strike Stryfe gun.

They started by cracking open the gun and making note of the available space for a few bells and whistles. Luckily, thanks to traditional plastic injection molding practices — there’s lots of room!

Upgrades include a magazine sensor, a jam sensor, a trigger sensor and a voltmeter to make the gun a little bit smarter. A knockoff Arduino Pro Mini takes in all these inputs and outputs it to a 7-segment LED display for easy visibility. Our favorite part is the ammo sensor, which keeps a tally of how many shots you’ve used. It’s simply an IR photo-diode and IR transistor in a Darlington configuration, connected to the GPIO interrupt pin on the fake Arduino.

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Sci-Fi Contest Roundup: The Valve Universe


While most of the entries to our Sci-Fi contest come from movies and TV shows, a select few are based on the Valve universe, including a few builds based on Portal and Team Fortress 2.

Deadly neurotoxinGLADOS

Who wouldn’t want a gigantic articulated sociopathic robot hanging around? Two groups are building a clone of GLaDOs from the Portal series. and already the builds look really great.

[AmarOk], developed an open-source personal assistant called RORI that intends to be a more helpful version of GLaDOs, without all the testing and killing. He, along with [Peterb0y] and [n0m1s] are turning this personal assistant software into a GLaDOs replica.

Taking a slightly different tack, [Eric] and [jjyacovelli] built a GLaDOs-like robot with a camera in the ‘face’. This camera connects to a Google Glass and tracks the user’s head movements. There’s also a Nerf gun attached to the end of the robot body, triggered by double winking. Yep, it’s a heads-up display GLaDOs, perfect for punishing your test subjects.

Heavy load comin’ through!


Not to be out done by a malevolent, hyper-intelligent artificial intelligence, [Tyler] and [Ryan] are building the cutest gat’ dern weapon in all of west Texas. It’s the level one sentry from Team Fortress 2, and the guys are turning one into a paintball sentry.

The TF2 sentry is a cute little bugger capable of motion tracking and perimeter defense, filling enemies with lead should they ever come too close.

While the end result probably won’t be as large or as heavy as the “official” real-life turret, a smaller table-top sized model is probably a little more practical. Even if it doesn’t live up to expectations, upgrading the sentry is simply a matter of whacking it with a wrench a few times.


There’s still time for you to cobble together an awesome Sci-Fi project and have a chance to win some awesome prizes.

Rubber Band Blaster Shoots 10 Rounds a Second

rubber band blaster

Office warfare has just been stepped up a notch and it’s time to hide in your cubicles! Enter the Rubber Band Blaster-32, a fully automatic rubber band handgun with switchable barrels for quick reloading.

It features a unique trigger release design that we haven’t seen before. By using a pull string release, [Dave] the inventor was able to load multiple rubber bands per barrel for individual firing, one by one. Hold down the trigger and as the firing wheel spins up, you can start shooting up to 10 rounds a second!

According to [Dave], reload time is around a minute per barrel, but the barrels can be stored loaded and ready to go, so pack a few mags and hang out behind the water cooler. That’s the last time [Bill] from accounting steals my stapler!

To see this puppy in action, sit tight after the break!

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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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