Planet Arduino

Well, here it is: a shoe-in for the new world’s largest NERF gun. (Video, embedded below.) The Guinness people haven’t shown up yet to award [Michael Pick], but at 12.5 feet, this baby is over twice as long as the current record holder, which belongs to former NASA mechanical engineer Mark Rober and his now-puny six-foot six-shooter.

We have to wonder if it is technically bigger than the six-shooter, because they seem to be roughly the same scale, except that [Michael] chose a much bigger model to start from. The main body is made from wood, and there are a ton of 3D-printed details that make it look fantastically accurate. The whole thing weighs over 200 pounds and takes at least two people to move it around. We especially love the DIY darts that [Michael] came up with, which are made from a PVC tube inside a section of pool noodle, topped off with a 3D printed piece for that distinctive orange cap.

Propelling those darts at around 50 MPH is a 3,000 PSI air tank connected to an Arduino Pro Mini that controls the trigger and the air valves. While [Michael] hasn’t run the thing quite that high, it does plenty of damage in the neighborhood of 40-80 PSI. As you’ll see in the video after the break, this is quite the ranged weapon. Watch it blow a hole clean through a sheet of drywall and much more.

Want to build something with a bit more stealth? Make it death from above with a NERF quadcopter.

Many of the projects we feature on Hackaday are motivated by pure greed. Not on the part of the hacker, mind you; but rather the company that’s charging such an outrageous price for a mass produced item that somebody decides they can do the same thing cheaper as a one-off project. Which is precisely how [Bryan Kevan] ended up building his own carbon fiber tube wrapping machine. Not only do the finished tubes look fantastic, but they cost him a fraction of what even the “cheap” commercial ones cost.

The principle behind producing the tubes is really pretty simple: carbon fiber ribbon (or “tow”, in the official parlance) gets wrapped around a rotating mandrel, ideally in interesting patterns, and epoxy is added to bind it all together. When it’s hardened up, you slide the new carbon fiber tube off the mandrel and away you go building a bike frame or whatever it is you needed light and strong tubes for. You could even do it by hand, if you had enough patience.

[Bryan] had done it by hand before, but was looking for a way to not only automate the process but make the final product a bit more uniform-looking. His idea was to rotate a horizontal PVC pipe as his mandrel, and move a “car” carrying the carbon fiber ribbon back and forth along its length. The PVC pipe just needs to rotate along its axis so he figured that would be easy enough; and using a GT2 belt and some pulleys, getting the carbon-laying car moving back and forth didn’t seem like much of a challenge either.

The frame of the winder is built from the hacker’s favorite: 20/20 aluminum extrusion. Add to that an Arduino Uno, two stepper motors with their appropriate drivers, and the usual assortment of 3D printed odds and ends. [Bryan] says getting the math figured out for generating interesting wrap patterns was a bit tricky and took a fair amount of trial and error, but wasn’t a showstopper. Though we’d suggest following his example and using party ribbon during testing rather than the carbon stuff, as producing a few bird nests at the onset seems almost a guarantee.

One of the trickiest parts of the project ended up being removing the carbon fiber tubes from the PVC mandrel once they were done. [Bryan] eventually settled on a process which involved spraying the PVC with WD-40, wrapping it in parchment paper, and then using a strip of 3M blue painter’s tape to keep the parchment paper from moving. If you can toss the whole mandrel in the freezer after wrapping to shrink it down a bit, even better.

So was all this work worth it in the end? [Bryan] says he was originally looking at spending up to $70 USD per foot for the carbon fiber tubes he needed for his bike frame, but by buying the raw materials and winding them himself, he ended up producing his tubes for closer to $3 per foot. Some might question the strength and consistency of these DIY tubes, but for a ~95% price reduction, we’d be willing to give it a shot.

Years ago we covered a Kickstarter campaign for a very similar carbon winder. Probably due to the relatively limited uses of such a gadget, the winder didn’t hit the funding goal. But just like the current wave of very impressive homebrew laser cutters, the best results might come from just building the thing yourself.

Last spring [Mike] built a foam rocket launchpad which was a hit with the kids in his neighborhood. But the launch system was merely a couple of buttons so the early enthusiasm quickly wore off. He went back to the drawing board to make improvements and really hit the jackpot!

The original launch system had one button for building up air pressure with a second big red button of doom for launching the rocket. The problem was a complete lack of user feedback; all the kids could do is guess how long they needed to hold the button to achieve the highest launch. This revision adds flashing LEDs to hold the attention of the wee ones but to also function as a gauge for the new pressure control system. The visually fascinating control board also includes a removable key to prevent accidental launches.

The particulars of this are as you’d expect: it’s a bunch of plumbing to manage the air pressure, an Arduino to control it all, and additional electronics in between to make them work together.

We’re especially impressed by the leap in features and quality from the first version to this one. It’s a testament to the power of quick proofs-of-concept before committing to a more involved build. Great work [Mike]!

We’ve seen rocket launchers for adults and some neat mission control panels but [Mike’s] kid friendly launch controller really is out of this world (sorry, couldn’t resist). You’ll find a video demo of this launcher after the break.