Controlling a spud gun with an Arduino

We’re a long way from the Aquanet-powered plastic pipe spud guns of our youth. [smirpab] over on the SpudFiles forum posted a work in progress of an amazing replica AS50 sniper rifle he’s building. This pneumatic cannon goes above and beyond any air-powered rifle we’ve seen with an Arduino that is able to switch between automatic, semi-automatic, and burst modes with an LCD display and a rate of fire control.

The mechanics of [smirpab]‘s build are fairly normal for this level of pneumatic gun; it shoots 6mm plastic pellets from a smooth bore barrel with using air compressed to about 10 bar (145 psi). The electronics is where this project really shines, with an Arduino controlling the mode of fire (auto, semi-auto, and a 3-round burst), and the number of rounds per second adjustable with a pot.

A very cool project, and looking at the CAD renders of what [smirpab] completed project will look like, we can’t wait to see this build finished. As always, this build comes with the standard Hackaday “you’ll put your eye out, kid” warning. You can check out a video of [smirpab]‘s piston after the break, along with a demo of the Arduino-powered control circuit going through all three firing modes.

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Pneumatic car launcher is actually more than just a hacker’s fantasy

So if you had to launch a car through these goal posts how would you do it? Certainly not with a slingshot (although we might have gone with a steam-powered catapult a-la an aircraft carrier). That maroon car with the white stripe is about to make the flight thanks to a very powerful pneumatic launcher.

We don’t usually attend the demolition derby, so this sort of thing is new to us. And we were even more surprised to find that this isn’t strictly a novelty act. The system is actually how some of the more dangerous automotive stunts are done for the movies. This launch sends the car in a graceful arc that is right on target and reminds us of the cliffhanger stunts from The Dukes of Hazzard (TV, not the recent movie). But if you’re a director looking for a horrific car accident, the rig can be altered to send the car spiraling through the air. Sounds like the record is nearly eight turns while airborne.

We don’t have any extra cars to launch, so we’ll stick to making the confetti fly.

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How to build a competitive battle robot

Ever wonder what’s under the hood with a competitive battle robot like this one? It’s usually a big secret as teams don’t care to give their competition any help. But [AlexHrn] decided not only to give us a peek, but also shows us his step-by-step build process for Phoenix, the 30 pound flipping battle robot.

[Alex] has already seen quite a bit of success with a different robot, but he couldn’t quite beat another competitor whose bot included a flipping arm which threw its competition across the ring. So [Alex] decided to join in on the technique with this build. The arm itself uses air pressure to exert a large force very quickly. Inside, a paintball gun tank powers the pneumatic ram. It looks like this tank is charged up before the competition and only gets about 12 shots before it’s depleted. You can see the power in the quick clip after the break.

For locomotion the unit uses a couple of cordless drill motors. These have a fairly high RPM and work well when powered by batteries.

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Old timey UAV cameras

These brave birds are weapons of war. Well, not these actual birds… they’re just models used for this photograph courtesy of a taxidermist. But their living relatives were used to take spy photographs during World War I. [Dr. Julius Neurbronner] didn’t suddenly jump into the field of avian photography. He, like his father before him, used homing pigeons to deliver prescription drugs in loads of up to 75 grams. This makes us wonder if the birds are ever used in modern drug running?

The inspiration came when the doctor found out about subminiature cameras available at the turn of the twentieth century. Those cameras included a tiny roll of film, allowing for several images to be taken. He figured out a way to make a timer that used a pneumatic system to trigger the shutter in the camera. You can see a diagram of the timer mechanism here. The idea is that the birds will always be able to find their way home. So if you take them to a starting point that puts the enemy lines in between them and home base, they’ll fly over and get some juicy recon in the process.

That’s pretty old school. But we’re still tying things onto birds these days. Here’s some modern tech that uses sun-up/sun-down to track travel habits.

[Thanks F via The Atlantic]

A Full Auto PVC Battery Gun

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So what’s better than a battery gun? A full auto pneumatic battery gun of course!  [ukilliheal], decided to build one of these, and show us the results in his video after the break.  After turning the gun on, this contraption shoots at a pretty impressive rate of fire (although, apparently not as fast as some of his other experiments).  Apparently batteries can do a pretty fair amount of damage to a cardboard target as shown around 1:20. [ukilliheal] apparently thinks this is pretty hilarious, but we wouldn’t want to be on the other end of this device!

Although details on this build are fairly slim in this video, [ukilliheal's] other videos should provide some clues, especially those where he explains how to make a full auto paintball gun.  If the same technique is used, a piston reloads the chamber using a homemade valve that releases pressure when it gets too high.  Electronics could also be used, but keeping everything mechanical will allow for the batteries to be used solely as ammuntion.

If full-auto guns aren’t your thing, why not check out this bolt-action miniature pneumatic spud gun!

Star Trek style pneumatic doors that don’t require a stagehand

In 1966, [Gene Roddenberry] introduced fully manual doors powered by a stagehand on Star Trek. The fwoosh sound of the door was later dubbed into each show, but progress marches on, and now [Alex] created his own Star Trek-style automatic doors for his house.

The build includes a ‘control panel’, and [Alex]‘s door operates in three modes: Open, and stay open; Close, and stay closed; and Automatic. The control panel itself is fairly remarkable. A small puck interacts with a magnetometer underneath [Alex]‘s counter. If the puck is pointed towards ‘Open’, the door stays open. If the door is pointed towards ‘Closed’, the door stays closed. If the puck isn’t near the magnetometer, the door operates in automatic mode with the help of a few IR sensors to detect someone trying to get in or out of [Alex]‘s kitchen.

For the mechanical portion of the build, [Alex] used a One meter long piston with the quietest air compressor he could find. We can’t tell from the video after the break if the compressor ever kicks in, but [Alex] says it’s about the same volume as his fridge. As a small added bonus, the new automatic door does have a fwoosh sound, just like [Gene] would have wanted.

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Halloween Hacks: A radioactive display with more trick than treat

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radioactive_barrel_display

[Shawn] was looking for a way to shake up his decorations this Halloween and decided to build a new prop for his front yard. He had a pair of old oil barrels in his garage and thought they would look great with a little bit of work.

He bolted the pair of barrels together, then slapped a fresh coat of black paint on them before adding a bright yellow radiation trefoil to each one. One barrel contains a pneumatic piston that opens the lid, revealing a light up pumpkin, a fog machine, and a set of water nozzles that spray the area. The second drum houses an air compressor, a wireless router, and an IP camera for recording the action. A web-enabled Arduino triggers the lid and sprayer, both of which can be controlled from the comfort of his house.

We think it’s a creative use of some old scrap barrels, but we’re hoping he doesn’t plan on wetting trick-or-treaters that pass through, as it seems  like a good way to get your house egged or otherwise vandalized on Halloween. If the water sprayer were perhaps swapped out with some other cool effects, [Shawn] is far less likely to be the target of some angry, wet teenagers.

Be sure to check out the video below to see the display in action.

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