A quick brush over the part with some sand paper and it quickly transforms from obviously plastic to metallic.

Learn Resin Casting Techniques: Cold Casting

July 14, 2016 by Gerrit Coetzee 36 Comments

Sometimes we need the look, feel, and weight of a metal part in a project, but not the metal itself. Maybe you’re going for that retro look. Maybe you’re restoring an old radio and you have one brass piece but not another. It’s possible to get a very metal like part without all of the expense and heat required in casting or the long hours in the metal fabrication shop.

Before investing in the materials for cold casting, it’s best to have practical expectations. A cold cast part will not take a high polish very well, but for brushed and satin it can be nearly indistinguishable from a cast part. The cold cast part will have a metal weight to it, but it clinks like ceramic. It will feel cool and transfers heat fairly well, but I don’t have numbers for you. Parts made with brass, copper, and iron dust will patina accordingly. If you want them to hold a bright shine they will need to be treated with shellac or an equivalent coating afterward; luckily the thermoset resins are usually pretty inert so any coating used on metal for the same purpose will do.

It is best to think of the material as behaving more or less like a glass filled nylon such as the kind used for the casing of a power tool. It will be stiff. It will flex a relatively short distance before crazing and then cracking at the stress points. It will be significantly stronger than a 3D printed part, weaker than a pure resin part, and depending on the metal; weaker than the metal it is meant to imitate.

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Wireless Robotic Gripper With Haptic Feedback

June 29, 2016 by Gerrit Coetzee 17 Comments

We’re not sure what kind of, “High School,” [Sam Baumgarten] and [Graham Hughes] go to that gave them the tools to execute their robotic gripper so well. We do know that it was not like ours. Apparently some high schools have SLS 3D printers and Solidworks. Rather than a grumpy shop teacher with three fingers who, despite that, kept taking the safety off the table saws and taught drafting on boards with so many phalluses and names carved into the linoleum, half the challenge was not transferring them to the line work.

Our bitterness aside, [Sam] and [Graham] built a pretty dang impressive robotic gripper. In fact, after stalking [Sam]’s linkedin to figure out if he was the teacher or the student, (student) we decided they’re bright enough they could probably have built it out of scraps in a cave. Just like [HomoFaciens], and Ironman.

The gripper itself is three large hobby servos joined to the fingers with a linkage, all 3D printed. The mechanical fingers have force sensors at the contact points and the control glove has tiny vibrating motors at the fingertips. When the force of the grip goes up the motors vibrate more strongly, providing useful feedback. In the video below you can see them performing quite a bunch of fairly fine motor skills with the gripper.

The gripper is mounted on a pole with some abrasive tape, the kind found on skateboard decks. At the back of the pole, the electronics and batteries live inside a project box. This provides a counterbalance to the weight of the hand.

The control glove has flexible resistors on the backs of the fingers. The signal from these are processed by an Arduino which transmits to its partner arduino in the gipper via an Xbee module.

[Sam] and [Graham] did a great job. They worked through all the design stages seen in professional work today. Starting with a napkin sketch they moved onto digital prototyping and finally ended up with an assembly that worked as planned. A video after the break explaining how it works along with a demo video.

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The Hacker Is The Future Of The Prosthetic: Hackers Helping Those In Need

June 8, 2016 by Gerrit Coetzee 4 Comments

In the show Full Metal Alchemist, there’s a city called Rush Valley whose main and only business are the high performance prostheses called Automail. Engineers roam the street in Rush Valley; the best have their own shop like that of the high-end clothiers in Saville Row. Of course; it’s all fantasy set in a slightly ridiculous Japanese cartoon, but while walking through this year’s Maker Faire I began to wonder if is a future that may come to be.

The problem with prosthetics is the sheer variety of injuries, body types, and solutions needed. If an injury is an inch higher or an inch lower it can have a big effect on how a prosthetic will interact with the limb. If the skin is damaged or the nerves no longer function a different type of prosthesis will be needed. Some prostheses are to replace a lost limb, others are to assist an ailing body in order to return it to normal function. More than a few are simply temporary aides to help the body along in its healing efforts. Unfortunately, this means that it’s often the case that larger companies only sell the prostheses people are most likely to need; the rarer cases are often left without a solution.

The e-Nable project doesn't mess around. — The e-Nable project doesn’t mess around.

However, we see hackers stepping up and not just working on the problems, but solving them. One of our semifinalists last year, openbionics, inspired one of the projects we’ll be talking about later. There are robotic legs. We met a guy at MRRF who has been 3D printing hands for his son from the E-nable project.

Along these lines, we saw two really cool projects at Maker Faire this year: The first is the Motor-Assistive Glove, or MAG. MAG is designed to help people with Peripheral Neropathy regain some use of their hands while they go through the lengthy road to recovery. Perhipheral Neuropathy is a disease, usually resulting from diabetes, toxin exposure, or infection, where the nerves are damaged in such a way that typically the hands and feet are no longer mobile or feel sensation in a useful way. Once the disease is in full swing, a previously able person will find themselves unable to do simple things like hold a can of soda or grasp a doorknob firmly enough to open it.

We had a chance to interview one of the members of the MAG team, [Victor Ardulov], which you can see in the following video. [Victor] and his group started a research project at the University of Santa Cruz to develop the Motor-Assistive Glove. The concept behind it is simple. People with Peripheral Neuropathy typically have some movement in their hands, but no strength. The MAG has some pressure sensors at the tips of the fingers. When the user puts pressure on the pad; the glove closes that finger. When the pressure is off; the glove opens. The concept is simple, but the path to something usable is a long one.

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Path To Craftsmanship: Safety, Cleanliness, And Documentation As Habits

May 12, 2016 by Gerrit Coetzee 49 Comments

When I started boxing classes I was told, at my level, I could do just as much good for my form by doing core exercises such as crunches, running, push-ups, and pull-ups for a month as I could by doing the class. I consder habits like safety, cleanliness, and documentation to be habits that influence the quality of hacks much the same way. They’re not really related, and the work can get done without them, but their implementation alone improves the quality of everything you do at the workbench.

The best mechanic I’ve ever met had a well-organized shop. All of his employees wore nitrile gloves when they worked on engines to protect their hands from the chemicals inside. They used ear protection and safety glasses. His rates were low, and the car was always repaired fast. I never had to go back for the same repair twice. He knew exactly what repairs were done, and even kept the parts removed from my vehicle to show me if I desired. I got some of the most fantastic explanations of why parts failed from him. Two blocks down the street was a shop which was unorganized and had double rates. The employees were always sitting on the waiting chairs in the lounge. It took one trip there to never return.

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Colin Furze Flies The Dangerous Skies

April 28, 2016 by Elliot Williams 111 Comments

To quote our tipster: “Furze is my hero … You just need to know how to weld and have zero consideration for your personal well-being.” We’re not exactly sure that he has no consideration, but [Colin Furze] definitely pulls off some dangerous hacks. This time? Two-engine hoverbike. We don’t have to tell you to watch the video, do we? Continue reading “Colin Furze Flies The Dangerous Skies” →

DIY Spot Welder Doesn’t Look Like It Will Immediately Kill You

April 24, 2016 by Gerrit Coetzee 30 Comments

We love hacks that involve mains voltage, but most of the time, for safety’s sake, we secretly hope for that one macabre commenter that details every imaginable way the questionable design choices will result in death. This spot welder may still be dangerous, but it looks like they took some precautions to make it non-lethal, and that counts for a lot.

After their extremely questionable high speed belt sander, this one is, refreshingly, extremely well done. It starts of as a dead standard microwave spot welder build: take apart microwave, try not to die from large capacitor, remove coil, modify coil, and hook up.

After that, it gets to some nice heavy metal music fabrication. Aside from a slightly shocking number of fresh OSHA reportable hand injuries (wear gloves!) the build goes together well. A lot of planning obviously went into it, from the actively cooled transformer to what appears to be a resettable timer circuit for the weld duration, not to mention the way that it just fit together so well at the end. There were some neat ideas as far as home mechanics go that we’ll be using in some of our projects.

In the end, the proof is in the spot-weld. The timer is set, pedal gets pressed down, and when tested, the sheet metal breaks instead of the weld. Video after the break.

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Hackaday Invades Toronto

April 14, 2016 by Brian Benchoff 5 Comments

Next Wednesday, April 20th, Hackaday will invade Toronto.

[Sophi Kravitz] and [Michael Guilfoil] are heading north of the border to meet up with our friends at HacklabTO. They’ll be hosting a Bring A Hack meetup with drinks, snacks, and swag.

Since this is a Bring A Hack, attendees are encouraged to bring whatever project you’re working on and show it off, give a lightning talk, and pitch it to the community. [Sophi]’s last visit to Toronto brought some crazy hardware to the meetup, including a gaming glove for a Commodore 64, a demonstration of Ontario’s power plants, testing hamburgers for anything that is not beef with PCR, and analog synthesizers.

Since the Hackaday Prize is in full swing, this is an excellent opportunity to team up with fellow Torontonians for a great Prize entry, or just bounce a few ideas off people to see if your idea is feasible.

The meet and greet at the Hacklab is free, but we would request that you RSVP for the event. The event is also on Hackaday.io, just in case you’d like to chat with [Sophi] or other attendees.

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