The Potowitzer: A Rapid Fire Potato Cannon

If you’ve ever fired a potato cannon, you’ll know that they are a raucous good time, but are somewhat clumsy to reload after each shot. Seeing an opportunity to improve on the design and minimize the delay between launches, [Danger First] have concocted a fast reloading potato cannon — or should I say — Potowitzer.

The key here is that they’ve gone through the extra effort of designing and building honest-to-goodness artillery rounds for their Potowitzer’s manual breech-loading mechanism. Foregoing the inconsistency of potatoes, they’ve 3D printed a bevy of bullets and sealed them with propane gas into PVC pipe cartridges. Metal contacts around the base to carry current from a BBQ lighter to the inside of the cartridge to ignite the propellant. Seeing it fire at about 18 rounds per minute is something special.

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Minecraft Sword Lights Up When Nearby Friends

With All Hallow’s Eve looming close, makers have the potential to create some amazing costumes we’ll remember for the rest of the year. If you’re a fan of the hugely addict-*cough* popular game Minecraft, perhaps you’ve considered cosplaying as your favorite character skin, but lacked the appropriate props. [Graham Kitteridge] and his friends have decided to pay homage to the game by making their own light-up Minecraft swords.

These swords use 3D-printed and laser-cut parts, designed so as to hide the electronics for the lights and range finder in the hilt. Range finder? Oh, yes, the sword uses an Arduino Uno-based board to support NewPixels LEDs and a 433Mhz radio transmitter and receiver for ranged detection of other nearby swords that — when they are detected — will trigger the sword to glow. Kind of like the sword Sting, but for friendlies. Continue reading “Minecraft Sword Lights Up When Nearby Friends”

Hackaday Prize Entry: Antigravity Arm Floaties

A few years ago, [Mike] heard about orthotic devices for people in wheelchairs that make it easier to them to move their arms. His daughter had the opportunity to demo one of these devices, and the results with the device were good. The fights with the insurance company were not so good, but this really was a device that could be made on a 3D printer with a few rubber bands, after all. Thus, [Mike] invented 3D printed antigravity arm floaties.

The name basically tells the story — these antigravity arm floaties work well to counter the pull of gravity for individuals with low muscle tone. [Mike]’s daughter found the professional, official, not-covered-by-insurance version useful, so [Mike] decided to build his own. There’s really not much to it – it’s just a few 3D printed parts attached to a wheelchair with a few rubber bands giving the mechanical linkages some resistance.

In the true hacker spirit, [Mike] took the basic idea of these spring-loaded arm floaties and put a new twist on it. He’s using a chain as the mechanism that allows freedom of movement in the XY plane. This makes the device slightly better, and is by every account an improvement on the commercial version. That’s what you get when you can iterate quickly with a 3D printer, making this project an excellent example of what we’re looking for in the Assistive Technology portion of the Hackaday Prize.

Hackaday Prize Entry: 3D Prints For The Visually Impaired

Students with visual impairments can have difficulty with visual and spatial relationships. 3D printers can print almost everything, and with a lot of CAD work, this project in the Hackaday Prize provides these students with physical objects to learn any subject.

[Joan] and [Whosawhatsis] have already written the book on 3D printed science projects and have produced a 3D printed Braille map of a campus, but for this project, they’re making things a little bit simpler. Visually impaired students are tactile learners and the simplest of their 3D printable objects are fixed volume objects. This collection of 3D printable cylinders, cones, prisms, and pyramids give a physical representation of geometric solids. These objects also have another trick up their sleeve: they all contain the same volume. Fill the cylinder up with water, pour that water into a cone, and the student will discover that they all contain the same volume.  That’s useful for the visually impaired, but would also put these printable shapes at home in any elementary or middle school math class.

This project already has a rather large following, with teachers of the visually impaired contributing on a Google Group, and a ton of people downloading the models. [Joan] and [Whosawhatsis] are getting a lot of great feedback and growing the range of contributors, making this the start of an awesome community and a great Hackaday Prize entry.

Monstrous Suit of Power Armor 3D Printed over 140 Days

fallout-armour-3d-printed-no-helmet[hirocreations] printed an entire suit of enormous Fallout power armor on his Monoprice Maker Select 3D printer, which took some 140 days and over 120 pounds of IC3D PLA filament. Happily, [hirocreations] was able to arrange a sponsorship with IC3D for the build – who would be crazy enough to use so much filament over so long for an entire 7+ foot tall suit, right? Over those 140 days, the belts on the printer needed to be replaced twice but it otherwise chugged right along.

Most of the parts were printed at 0.46 mm layer height. Individual parts were welded (melted) together using what is essentially a soldering iron with a flat tip; many parts were too thin for any kind of joints or fixtures to be practical. Parts were smoothed with drywall spackle, lots of filler primer, and painted. Some of the parts – like the chest armor – are mounted on a frame made from PVC tubing. [hirocreations] may have gone through 120 pounds of filament, but the end result doesn’t weigh that much; the suit itself weighs in at 85-90 lbs, the rest of it went to support material, skirts, and print failures.

It was known from the start that weight could become a serious issue, so [hirocreations] went for a very light infill (10%) and 3-4 perimeter layers; he also extruded at a high temperature (~230C) which he said seemed to provide a very strong layer bond with the settings and filament he was using. So far, he says it’s taken some very hard knocks and nothing has broken or cracked. He has a short video series documenting the assembly, and you can see some of the raw armor parts before any finishing in one of the videos, embedded below.

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Hackaday Prize Entry: A 3D Printed Prosthetic Foot

For the last few years of the Hackaday Prize, there have been more than a few prosthetic devices presented. Almost without exception, the target for these projects are prosthetic hands. That’s a laudable goal, but mechanically, at least, feet are much more interesting. A human foot must sustain more than the weight of the human it’s attached to, and when it comes to making this out of plastic and metal, that means some crazy mechanics.

This Hackaday Prize entry is a complete reversal of all the prosthetic limbs we’ve seen before. It’s a prosthetic foot, and in the tradition of easily made and easily modified prosthetic arms, this prosthetic foot is mostly 3D printed.

A foot will take a lot more abuse and weight than a hand, and because of this 3D printing all the parts might not seem like the best idea. Exotic filaments exist, though, and the team behind this project does have access to a few pieces of test equipment in a materials engineering lab. With the right geometry, everything seems to support the load required.

There are some relatively new twists to this 3D printed prosthetic foot, including electronic control, a micro-hydraulic power plant, and sensors to measure and adjust the user’s gait. It’s all very cool, and deserves a lot more engineering than even the most complicated 3D printed prosthetic hand.

3D Printed Nozzles Turbocharge Microsphere Production

Researchers at MIT have used 3D printing to open the door to low-cost, scalable, and consistent generation of microencapsulated particles, at a fraction of the time and cost usually required. Microencapsulation is the process of encasing particles of one material (a core) within another material (a shell) and has applications in pharmaceuticals, self-healing materials, and dye-based solar cells, among others. But the main problem with the process was that it was that it was slow and didn’t scale, and it was therefore expensive and limited to high-value applications only. With some smart design and stereolithography (SLA) 3D printing, that changed. The researchers are not 3D printing these just because they can; they are printing the arrays because it’s the only way they can be made.

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