Automatic Nerf Sentry Gun

I built this Nerf Sentry Gun by grafting a couple of Arduinos, a power supply, a motor, and an ultrasonic distance sensor onto a Nerf Vulcan machine gun. I posted these build notes on Make: online. I’ve never compiled them all in one place, however, so this post serves to tie the whole project together in one place.

Part 1: Wiring the trigger

The first step was to add wiring and a two-wire connector to control the trigger circuit. I opened up the Nerf Vulcan (about 30 screws) and soldered an 1/8″ female jack to the fire selection mode switch. This way, I can retain all the regular functions of the gun when it’s unplugged from the Arduino. To control it from the Arduino, I’ll flip the orange switch on top to “off” and then wire the trigger into the “pulled” position (done here with a classy twist tie). Whenever the Arduino’s trigger circuit closes (bypassing that orange “off” switch) the gun will start firing.

To add the connector, I drilled a 1/4″ hole in the gun’s hand grip, fed the sleeve through, and secured it with a couple of zip ties inside for strain relief.

Next, I’m planning to build the Arduino’s trigger circuit using a MOSFET transistor wired to a male 1/8″ jack I can plug into the gun.

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SPLixel Sweeper

Sometimes its fun to build and code a little project to test new hardware, as well as just for the heck of it. I built this demo thing with a Spikenzie Labs SPLixel board and LED strip, Arduino, and ScrewShield. I read one knob to control the position (which LED is lit), the other controls the green component of the color mix.

In order to keep the knobs from moving around too much, I screwed some small c-clamps onto them.

It’s fun to play with. A little bit.

Imperial Melody Discharger – Stormtrooper helmet art build notes

I built the Imperial Melody Discharger, an articulated Stormtrooper helmet music box, for the Star Wars Day (“May the 4th be with you”) vinyl Stormtrooper helmet art show . For the event, artists across the Walt Disney Company, including DisneyToon Studios where I work, were invited to participate by using a blank 6″ helmet as the canvas for their work. What follows are my build notes and work in progress images.

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My intention for the piece was to provide a view behind the mask of the anonymous Stormtrooper, while creating a fun, interactive moment for the person experiencing it. I wasn’t sure exactly how to get there, but I was certain I’d need to cut the vinyl helmet open. You only have one shot at that, so I decided to first cut apart a CG model inside Maya, and rig it with pivot points that could be used in the real world for the facial articulation.

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Mostly satisfied that I knew where to separate the parts of the helmet, I grabbed an X-acto knife, took a breath, and began the incision. (Note: It smelled really foul in there. Also note: I have no way to compare the smell to that of the insides of a tauntaun.)

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Once splayed out I wasn’t too surprised to see that the “pelt” of the helmet was darned floppy. I needed to build an armature to keep the structure solid, and to support the articulation of the two halves of the face mask.

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With very little time to get fancy building parts from scratch, I rummaged around my workshop, closets, and shamefully disorganized garage, until I came upon an old spider Babyface homage to Toy Story I’d build back in ’95 out of Erector sets. Sorry, Spider Baby, I needed your body parts.

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Arduino GRANDE at Maker Faire

IMG_5056 by JohnEdgarPark
IMG_5056, a photo by JohnEdgarPark on Flickr.

This is my Maker Faire Bay Area 2012 project, the Arduino GRANDE. It is a fully functional Arduino that is about six times larger than real life. Come hear all about it at the Maker Faire this coming weekend, May 19th and 20th. I’ll be doing talks and demos on Saturday. http://makerfaire.com/pub/e/8185