The ballistics of humble potato is a time-honoured research topic for everyone who likes things that go bang. The focus of such work is usually on the launcher itself, with the projectiles being little more than an afterthought. [drenehtsral] decided that the wares of the local organic ammunition supplier were not good enough for him and his minions, so he designed and then 3D printed some rifled potato cannon slugs.
The design was done using OpenSCAD, has a number of adjustable parameters like infill and rifling. We doubt that the rifling introduces any spin, since it is being fired from a smooth bore barrel, but as always 3D printing brings the capability to quickly test different ideas. A quick search on Thingiverse shows a number of 3D printed spuds, so [drenehtsral] is not the first give it a go. However, this did bring to our attention that the field of spud gun projectiles is begging to be explored.
There is enough space inside a projectile to fit an IMU and logging electronics, which would give some very nice empirical data (providing you can recover it of course) on spin, acceleration, and trajectory that can be used to further improve designs. Spring loaded stabilising fins would be cool, and maybe someone can even manage to implement some form of guidance? The possibilities are endless! If you’re up for the challenge, please document your work it and let us know.
As you would expect we have no shortage of potato cannon themed content, ranging from cartridge firing and bolt action versions to antenna launchers and Arduino-powered fire control systems.
We live in an amazing time where the availability of rapid prototyping tools and expertise to use them has expanded faster than at any other time in human history. We now have an amazing ability to quickly bring together creative solutions — perfect examples of this are the designs for specialized arm prosthetics, Braille printing, and custom wheelchair builds that came together last week.
Earlier this month we published details about the S.T.E.A.M. Fabrikarium program taking place at Maker’s Asylum in Mumbai. The five-day event was designed to match up groups of makers with mentors to build assistive devices which help improve the condition of differently-abled people.
The participants were split into eight teams and they came up with some amazing results at the end of the five-day program.
Hands-On: Prosthetic Designs That Go Beyond
Three teams worked on projects based on Bionico – a myoelectric prosthesis
DIY Prosthetic Socket – a Human Machine Interface : [Mahendra Pitav aka Mahen] lost his left arm during the series of train bomb blasts in Mumbai in 2006, which killed 200 and injured over 700 commuters. He uses a prosthetic arm which is essentially a three-pronged claw that is cable activated using his other good arm. While it is useful, the limited functionality restricted him from doing many simple things. The DIY Prosthetic socket team worked with [Mahen] and [Nico Huchet] from MyHumanKit (who lost his right arm in an accident 16 years back), and fabricated a prosthetic forearm for [Mahen] with a modular, 3D printed accessory socket. Embedded within the arm is a rechargeable power source that provides 5V USB output at the socket end to power the devices that are plugged in. It also provides a second port to help recharge mobile phones. Also embedded in the arm was an IR reflective sensor that can be used to sense muscle movements and help trigger specific functions of add-on circuits, for example servos.
Continue reading “Rapidly Prototyping Prosthetics, Braille, And Wheelchairs”
[Eric Strebel] is quickly becoming a favorite here at Hackaday. He’s got a fantastic knack for turning everyday objects into something awesome, and he’s kind of enough to document his builds for the viewing pleasure of hackers and makers everywhere. It also doesn’t hurt that his voice and narration style gives us a real Bob Ross vibe.
The latest “Happy Accident” out of his workshop is a neat light-up cane made from a ceramic skull found at a local store. But while the finished cane itself might not be terribly exciting, the construction methods demonstrated by [Eric] are well worth the price of admission. Rather than using Bondo like the filler we’re all accustomed to, he shows how it can be used to rapidly build free-form structures and components.
After building up layers of Bondo, he uses a cheese grater to smooth out the rough surface and a hobby knife to clean up the edges. According to [Eric], one of the benefits of working with Bondo like this is that it’s very easy to shape and manipulate before it fully hardens; allowing you to really make things up as you go.
[Eric] also shares a little secret about how he makes his gray Bondo: he mixes some of the toner from a laser printer cartridge into it. This allows you to very cheaply augment the color of the filler, and is definitely something to file away for future reference.
If the video below leaves you hungry for more [Eric Strebel], check out his fantastic series on working with foam core, which should lead you right down the rabbit hole to his DIY foam core spray painting booth.
Continue reading “Skull Cane Proves Bondo Isn’t Just For Dents”
Here on Hackaday, too often do we turn our heads and gaze at the novelty of 3D printing functional devices. It’s easy to forget that other techniques for assembling functional prototypes exist. Here, [Reuben] nails the aspect of functional prototyping with the laser cutter with a real-world application: a roll-pitch friction differential drive built from just off-the shelf and laser-cut parts!
The centerpiece is held together with friction, where both the order of assembly and the slight wedged edge made from the laser cutter kerf keeps the components from falling apart. Pulleys transfer motion from the would-be motor mounts, where the belts are actually tensioned with a roller bearing mechanism that’s pushed into position. Finally, the friction drive itself is made from roller-blade wheels, where the torque transferred to the plate is driven by just how tightly the top screw is tightened onto the wheels. We’d say that [Reuben] is pushing boundaries with this build–but that’s not true. Rather, he’s using a series of repeatable motifs together to assemble a both beautiful and complex working mechanism.
This design is an old-school wonder from 2012 uncovered from a former Stanford course. The legendary CS235 aimed to teach “unmechanically-minded” roboticists how to build a host of mechanisms in the same spirit as MIT’s How-to-make-almost-Anything class. While CS235 doesn’t exist anymore, don’t fret. [Reuben] kindly posted his best lectures online for the world to enjoy.
Continue reading “Friction Differential Drive Is A Laser-Cut Triumph”
Join [Sylvia Wu], a Senior Manufacturing Engineer at Fictiv, for this week’s Hack Chat. [Sylvia’s] work at Fictiv gives her a unique viewpoint for modern manufacturing. The company connects engineers with rapid manufacturing by taking in a design and routing it to a shop that has the tools and time to fabricate the part quickly. This means seeing the same silly mistakes over and over again, but also catching the coolest new tricks as they pass by. She also spends time tearing apart consumer products to see how they have been manufactured, adding to their arsenal of available processes, both time-tested and newfangled.
Anyone interested manufacturing needs to get in on this Hack Chat. Mark your calendar for this Friday, 3/10 at noon PST (20:00 UTC)
Here’s How To Take Part:
Our Hack Chats are live community events on the Hackaday.io Hack Chat group messaging.
Log into Hackaday.io, visit that page, and look for the ‘Join this Project’ Button. Once you’re part of the project, the button will change to ‘Team Messaging’, which takes you directly to the Hack Chat.
You don’t have to wait until Friday; join whenever you want and you can see what the community is talking about.
Upcoming Hack Chats
On Friday March 17th the Hack Chat features chip design for oscilloscopes with engineers from Keysight.
Nadya Peek is one of the hackers that should require no introduction for the regular Hackaday reader. She is a postdoc at the Center for Bits and Atoms at the MIT Media Lab. She’s responsible for Popfab, a CNC machine that fits in a suitcase and one of the first implementations of a Core XY stage we’ve seen. Nadya has joined the ranks of Rudolf Diesel, Nikola Tesla, Mikhail Kalashnikov, and George W.G. Ferris by having a very tiny piece of the Novena laptop bear her name. She’s built cardboard CNC machines, and taken the idea of simple, easy to build printers, routers, and drawbots worldwide. She just defended her thesis, the gist of which is, ‘How to rapidly prototype rapid prototyping machines.’ She’s also one of this year’s Hackaday Prize judges, for which we have the utmost appreciation.
This year, the organizers of the Fab 12 conference on digital fabrication in Shenzhen turned to Nadya and her team to bring their amazing experience to conference attendees. A workshop was in order, but Nadya didn’t have time to organize the logistics. The conference organizers made a deal: the Center for Bits and Atoms would teach a workshop, but getting all the materials and electronics was the responsibility of the organizers.
Upon arriving at the Shenzhen Sheridan, Nadya found the organizers didn’t hold up their end of the bargain. The cardboard, motors, electronics, and glue were nowhere to be found. A “rider” doesn’t quite translate from English, it seems. This is Shenzhen, though, where you can buy all the cardboard, motors, electronics, and iPhone clones you could imagine. What was the solution to this problem? Founding a company in Shenzhen for eight days.
Half a tourist’s guide to Shenzhen and half a deconstruction of what goes into cardboard CNC, Nadya’s talk for the 2016 Hackaday SuperConference covers what happens when you have a week to build a company that will build machines that build machines.
Continue reading “Founding A Company In Shenzhen For Eight Days”
The “Navigation Thing“ was designed and built by [Jan Mrázek] as part of a night game activity for high school students during week-long seminar. A night-time path through a forest had stations with simple tasks, and the Navigation Thing used GPS, digital compass, a beeper, and a ring of RGB LEDs to provide a bit of “Wow factor” while guiding a group of students from one station to the next. The devices had a clear design direction:
“I wanted to build a device which a participant would find, insert batteries, and follow the beeping to find the next stop. Imagine the strong feeling of straying in the middle of the night in an unknown terrain far away from civilization trusting only a beeping thing you found. That was the feeling I wanted to achieve.”
The Navigation Things (there are six in total) guide users to fixed waypoints with GPS, a digital compass, and a ring of WS2812 LEDs — but the primary means of feedback to the user is a beeping that gets faster as you approach the destination. [Jan] had only four days to make all six units, which was doable. But as most of us know, delivering on a tight deadline is often less about doing the work you know about, and more about effectively handling the unexpected obstacles that inevitably pop up in the process.
Continue reading “Navigation Thing: Four Days, Three Problems, And Fake Piezos”