3D Printing A Prosthetic-Compatible Golf Club

September 2, 2022 by Danie Conradie No comments

Relearning an old sport, or starting a new one, can be challenging for amputees. Besides the obvious physical aspects, custom prosthetics or adaptors might need to be made and fitted, which can be very expensive. With the power of 3D printing and some machining, [Ian Davis] was able to build a custom prosthetic golf club to get a quadruple amputee back on the greens.

The recipient of this prosthetic lost both hands above the wrists, so [Ian] had to come up with a mechanism that could hold the club and mimic wrist motion throughout the swing. He was able to achieve this motion with a simple four-plate hinge for each arm. For optimal ergonomics, [Ian] also added two-axis adjustability, with only a single bolt needing to be loosened per axis. A standard golf club can be used and is clamped in the printed holders.

Machined prosthetic sockets were used to allow quick connection to the user’s existing prosthetic forearms. Theoretically, this should also allow him to switch clubs without excessive hassle. [Ian], an amputee himself, has used his engineering skills to build a series of prosthetic hands and even a custom controller mod to get back to gaming with fewer flesh fingers.

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Fixing A Hot Shop, With Science

September 2, 2022 by Dan Maloney 42 Comments

We know that pretty much everybody in the Northern hemisphere has had a hellish summer, and there’s little room for sympathy when someone busts out with, “Oh yeah? You think THAT’s hot? Well, lemme tell you…” But you’ve got to pity someone who lives in north Texas and has a steel Quonset hut for a shop. That’s got to be just stupidly hot.

But stupid hot can be solved — or at least mitigated — with a little smarts, which is what [Wesley Treat] brought to bear with this cleverly designed shop door heat shield. When it pushes past 42°C — sorry, that sounds nowhere near as apocalyptic as 108°F — the south-facing roll-up door of his shop becomes a giant frying pan, radiating heat into his shop that the air conditioner has trouble handling. His idea was to block that radiant heat with a folding barrier, but to make sure it would be worth the effort, he mocked up a few potential designs and took measurements of the performance of each. His experiments showed him that a layer of extruded polystyrene (XPS) foam insulation covered with reflective Mylar did better than just the foam or Mylar alone.

The finished heat shield is an enormous tri-fold plywood beast that snugs up against the door when things get toasty in the shop. There’s a huge difference in temperature between the metal door and the inside surface of the shield, which will hopefully keep the shop more comfortable. We imagine that the air between the door and the shield will still heat up, and convection could still distribute all that hot air into the shop. But at least he’s giving the AC a fighting chance.

In addition to great shop tips like this and his custom storage bins, [Wesley] is a talented signmaker. He’s pretty funny too — or maybe that’s just the heat talking.

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Cutting The Grass With Frickin’ Lasers

September 2, 2022 by Dave Rowntree 29 Comments

We techie types are quite often much more comfortable in front of a keyboard knocking out code, than out in the yard splitting logs for winter, and even the little jobs like cutting the grass are sometimes just too much like hard manual labour for our liking. The obvious solution is a robot mower, but they’re kinda boring, with their low-tech spinning metal blades. What we need is a big frickin’ laser. YouTuber [rctestflight] has been experimenting with using a 40W blue diode laser module to cut the weeds, (Video, embedded below) and it sort of works, albeit in a rather dangerous fashion.

The first test used a fixed assembly, mounting the laser to a camera lens, upon a rotating gear driven by a small stepper motor. An Arduino controls the beam scanning, very slowly, burning the grass in its sights. But with a range limited to around eight feet best case, sitting in one spot just isn’t going to cut it. (sorry) The obvious next step was to mount one of the tested laser modules onto a moveable platform. After tweaking one of his earlier projects — a tracked rover — with a new gearbox design, it could now drive slow enough to be useful for this slow task. The laser was mounted to a simple linear rail slider, with an attempt at a vacuum pickup system to suck up the clippings, removing them from the beam path, and stopping them impeding the cutting efficiency of the laser.

Obviously this vacuum idea didn’t work, and since the contraption takes the best part of a week to cut just one small area, we reckon it would likely be growing faster than that! Still, it must have been fun to build it anyway. It just goes to show that despite the march of technological progress, maybe the boring old spinning blades of old are still the best way to get the job done.

Lawnmowing is clearly one of those jobs we love to hate, and do so with hacks. Here’s a way to prevent your mower sucking up foreign bodies and hurling them at you at ballistic speeds, and for those who really want to be hands off, add RTK-GPS to a robot mower, and just leave it to do the dirty work.

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Magnetic Gearbox Can Go Fast But Not Hard

September 2, 2022 by Danie Conradie 13 Comments

3D printed gearboxes are great for experimental designs, but due to roughness and inaccuracies in the printed surfaces, they can wear quickly and be rather noisy. As a possible alternative, [Resetman] is experimenting with magnetic 3D printed gearboxes that work without physical contact between the rotating wheels, and can also be “geared” for different ratios in some interesting ways.

Naturally, two closely spaced wheels with magnets will interact with each other, with the ratio defined by the number of magnets on each wheel. A much less obvious implementation is a second-order radial flux coaxial magnetic gearbox. It works similar to a normal planetary gearbox, with an outer and inner wheel containing magnets, and an intermediate ring known as a flux modulator, containing equally spaced pieces of ferromagnetic steel metal. In [Resetman] demonstration, the flux modulator is just a 3D printed ring screws around its circumference.

The most obvious disadvantage is of course severely limited torque transfer. [Resetman] could easily accelerate the sun wheel to 12,000 RPM if the flux modulator is accelerated slowly, but any sudden changes in speed would cause it to lose synchronization. Of course, you can consider this a torque-limiting feature for certain use cases. With a bit of testing, he determined the torque limit at a 1:4 ratio was a meager 0.05 Nm. This could be increased by some optimization, for example rearranging the magnets to form Halbach arrays, and reducing the air gaps between the components.

Magnetic gearboxes are nothing new, we’ve featured another demonstrator before, and even did an “Ask Hackaday” on the subject. What would you use these for? Let us know below.

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Hackaday Prize 2022: A Cooler For Your Footwear

September 2, 2022 by Lewin Day 15 Comments

Sweaty feet can be uncomfortable, and the smell generated in one’s shoes isn’t much to admire, either. In an effort to help solve this issue, [Revoxdyna] has created a cooler for one’s feet that should help out in hot conditions.

Modern shoes, particularly sneakers, are often ventilated, but it’s not always enough. This build takes things further, using active cooling. Water is pumped through tubes and into a copper insole which cools the sole of the foot. It’s achieved thanks to a pump assembly that mounts to the rear of the shoe in a 3D printed housing. The water itself is chilled with a thermoelectric cooler, which helps remove heat from the shoe area.

There is some bulk to the design, which would prevent its use in performance applications in its current form. However, we could imagine companies like Nike leaping at the chance to build some very fancy, high-tech shoes along these lines in future. After all, they already managed to create power laces, and this is even cooler again! Pun definitely intended.

This Week’s Hack Chat Sets The Stage For Supercon

September 2, 2022 by Tom Nardi No comments

While the 2020 and 2021 Remoticons were a blast, we all know that virtual events are no substitute for in-person conferences. Which is why we’re so excited to once again invite the Hackaday community to converge on Pasadena in November for a weekend of talks, workshops, and hardware hacking for our sixth Supercon.

To help get the community prepared for the triumphant return of what we very humbly believe to be the greatest hardware hacking conference the world has ever seen, we invited Majenta Strongheart to this week’s Hack Chat to answer the community’s questions about this hotly anticipated event. There’s an incredible number of moving pieces involved in an event like Supercon, and as Head of Design and Partnerships at our parent company SupplyFrame, she’s integral to putting them all together right up until the doors open on November 4th.

The Chat kicked off with a general confirmation that yes, we did receive your talk and/or workshop proposal. It seems several people didn’t receive the intended confirmation message when they sent their information on, but Majenta assured everyone that all of the completed forms were received correctly and are currently under review. If you put in a proposal, you should be notified in the next few weeks about whether or not it was accepted.

With that out of the way, the next big question was the one that so many of you have been wondering: what does the Hackaday Supercon look like in the era of COVID? The truth is, things are still evolving and it’s hard to be sure of anything with two more months to go. But Majenta did confirm that the decision has been made to limit ticket sales compared to previous years so that attendees have a bit more breathing room — literally and figuratively. In addition many of the planned events will be held outdoors, and the talks will be streamed live for anyone who’d rather not sit in the audience.

Majenta also took this opportunity to let everyone know that the volunteer application form for Supercon will be available very soon, and that as usual, those who are willing to help out will get a free ticket in exchange. Speaking of which, if you’d rather pay the gold price, General Admission tickets for the 2022 Supercon are currently on sale.

As you might imagine, Majenta has been exceptionally busy as of late, so we appreciate her taking the time to sit down with us and Chat. If you couldn’t make this live discussion about Supercon, don’t worry. You can send questions, ideas, or comments, to superconference@hackaday.io and we’ll see what we can do.

The Hack Chat is a weekly online chat session hosted by leading experts from all corners of the hardware hacking universe. It’s a great way for hackers connect in a fun and informal way, but if you can’t make it live, these overview posts as well as the transcripts posted to Hackaday.io make sure you don’t miss out.

Robot Brutally Chops But Makes Poor Guacamole

September 2, 2022 by Lewin Day 27 Comments

Making guacamole by hand normally takes [Estefannie] about 9 minutes. Given her insatiable appetite for the delicious condiment, she spends a lot of time whipping it up in the kitchen at home. Thus, it’s a task ripe for automation, and she set about building a robot to do the job instead.

The robot starts by chopping ingredients like tomato, onion, and avocado with a knife that swivels to cover the entire chopping board surface. Once chopped, a sweeping blade pushes the ingredients into a bowl to form the guacamole.

Initial tests were messy, and ingredients were chopped a little inconsistently. Later work involved reprogramming the machine to chop ingredients separately, rather than all at once, which did improve the quality of the guacamole significantly. However, fundamentally, it wasn’t making good guac, so much as it was making a very chunky salad. It simply couldn’t do all the complicated jobs required to make a smooth, delicious dip.

[Estefannie] elected to instead let it live out its life as a mighty chopper, showing off its prowess by having it attack candy, cake, watermelon, and chocolate, which was pretty fun to watch. It bears noting that if you’re building a robot that swings a blade around, you need to be very careful. If you’re looking for something a bit safer, perhaps a Taco Bot is in your future.

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