3D-Printed Halbach Motor Part Two: Tuning, Testing

Building your own Halbach-effect brushless DC motor is one thing. Making sure it won’t blow up in your face another matter, and watching how [Christoph Laimer] puts his motor to the test is instructive.

You’ll remember [Christoph]’s giant 3D-printed BLDC motor from a recent post where he gave the motor a quick test spin. That the motor held together under load despite not being balanced is a testament to the quality of his design and the quality of the prints. But not wishing to tempt fate, and having made a few design changes, [Christoph] wisely chose to perform a static balancing of the rotor. He also made some basic but careful measurements of the motor’s parameters, including the velocity constant (Kv) using an electric drill, voltmeter, and tachometer, and the torque using a 3D-printed lever arm and a kitchen scale. All his numbers led him to an overall efficiency of 80%, which is impressive.

[Christoph] is shipping his tested BLDC off to the folks at FliteTest, where he hopes they put it to good use. They probably will — although they might ask for three more for a helicarrier.

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Fly Across The Water On A 3D-Printed Electric Hydrofoil

Paddleboards, which are surfboard-like watercraft designed to by stood upon and paddled around calm waters, are a common sight these days. So imagine the surprise on the faces of beachgoers when what looks like a paddleboard suddenly but silently lurches forward and rises up off the surface, lifting the rider on a flight over the water.

That may or may not be [pacificmeister]’s goal with his DIY 3D-printed electric hydrofoil, but it’s likely the result. Currently at part 12 of his YouTube playlist in which he completes the first successful lift-off, [pacificmeister] has been on this project for quite a while and has a lot of design iterations that are pretty instructive — we especially liked the virtual reality walkthrough of his CAD design and the ability to take sections and manipulate them. All the bits of the propulsion pod are 3D-printed, which came in handy when the first test failed to achieve liftoff. A quick redesign of the prop and duct gave him enough thrust to finally fly.

There are commercially available e-foils with a hefty price tag, of course; the header image shows [pacificmeister] testing one, in fact. But why buy it when you can build it? We’ve seen a few hydrofoil builds before, from electric-powered scale models to bicycle powered full-size craft. [pacificmeister]’s build really rises above, though.

[pacificmeister], if you’re out there, this might be a good entry in the Hackaday Prize Wheels, Wings, and Walkers round. Just sayin’.

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An Enchanted Rose For A Beauty

Being a maker opens up so many doors in terms of ways to romance one’s partner through passion projects. If their passion is Disney films, then you may handily make them the enchanted rose from Beauty and the Beast for their birthday. Easy-peasy.

In addition to the love and care that went into this build, redditor [Vonblackhawk2811] has included a set of LEDs, salvaged from cheap flashlights and electronic candles, which are controlled by four toggle switches and offer multiple lighting selections — candlelight, soft white, colour cycling, and bright white — to appropriately set the mood. As if that wasn’t enough to romance his sweetheart, he’s also included an aux cord input and a pair of speakers so they may be serenaded by a tune or two as they dance the night away.

Liberal use of hot glue and duct tape are keeping the electronics secured, preventing any shorts. After all — what would it say if this gift went up in flames? An inspired stencil design — hand drawn and cut out — was used to apply a spray-on frosted glass finish to the cloche, and a romantic phrase was burned into the base, completing this heartfelt gift. The only quibble we have is that now we all have to step up our game in the courtship department.

That is, unless one is sporting the Romance Pants.

[via /r/DIY]

Dual-Purpose DIY Spot Welder Built With Safety In Mind

Ho-hum, another microwave oven transformer spot welder, right? Nope, not this one — [Kerry Wong]’s entry in the MOT spot welder arms race was built with safety in mind and has value-added features.

As [Kerry] points out, most MOT spot welder builds use a momentary switch of some sort to power the primary side of the transformer. Given that this means putting mains voltage dangerously close to your finger, [Kerry] chose to distance himself from the angry pixies and switch the primary with a triac. Not only that, he optically coupled the triac’s trigger to a small one-shot timer built around the venerable 555 chip. Pulse duration control results in the ability to weld different materials of varied thickness rather than burning out thin stock and getting weak welds on the thicker stuff. And a nice addition is a separate probe designed specifically for battery tab welding — bring on the 18650s.

Kudos to [Kerry] for building in some safety, but he may want to think about taking off or covering up that ring when working around high current sources. If you’re not quite so safety minded, this spot welder may or may not kill you.

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Oscilloscope Mod For The Blues

Roughly 8% of males and 0.6% of females are red-green color blind, and yet many common oscilloscopes use yellow and green for the traces for their two-channel readouts. Since [Roberto Barrios] is afflicted by deuteranopia, a specific form of red-green colorblindness that makes differentiating between yellow and green hard, if not impossible, he got to work hacking his Agilent oscilloscope to make it more colorblind friendly.

Starting with a tip from [Mike] from the EEVblog forums, [Roberto Barrios] set out to rewire the LCD interface and swap the red and green signals. That way yellow will turn bluish (red component replaced by blue) and it could be seen as “very different now” from the green trace on the readouts. Sounds simple right? Well, slight issue: the 0.5 mm pitch of the connector. He did not want to design a PCB and wait a few weeks to receive it, so he decided on using 0.1 mm wires held together with Kapton tape to route each signal individually from one connector to the other. After an hour under the microscope, it was done. And boy, his work is impressive, go check it out.

Voila! It worked splendidly. Now [Roberto Barrios] can use his scope. And, the stock UI is mostly grey or white, so swapping the red and blue channels did not change much the appearance of the interface. Moreover, the switch had a small unintentional bonus, the loading screen is much cooler now with an edgy red sky. Further, [Roberto Barrios] “would not be [himself] if [he] could resist changing the CH1 button backlight LED to blue, to match the new trace color. So, no [he] couldn’t.”

This was a well done and very functional oscilloscope mod, but if you need more frivolity in your life, fear not: we’ve got your back with real-time Quake played on an oscilloscope.

A Goldmine Of Radio Shack Goodies Is Up For Auction

Where did you buy the parts for your first electronic project? That’s a question likely to prompt a misty-eyed orgy of reminiscences from many Hackaday readers, if ever we have heard one. The chances are that if you are from North America or substantial parts of the English-speaking world, you bought them from a store that was part of the Radio Shack empire. These modestly sized stores in your local mall or shopping centre carried a unique mix of consumer electronics, CB radio, computers, and electronic components, and particularly in the days before the World Wide Web were one of very few places in which an experimenter could buy such parts over the counter.

Sadly for fans of retail electronic component shopping, the company behind the Radio Shack stores faltered in the face of its new online competition over later years of the last decade, finally reaching bankruptcy in 2015. Gone are all but a few independently owned stores, and the brand survives as an online electronics retailer.

The glory days of Radio Shack may be long gone, but its remaining parts are still capable of turning up a few surprises. As part of the company’s archives they had retained a huge trove of Radio Shack products and memorabilia, and these have been put up for sale in an online auction.

There is such a range if items for sale that if you are like us you will probably find yourself browsing the listings for quite a while. Some of it is the paraphernalia of a corporate head-office, such as framed artwork, corporate logos, or strangely, portraits of [George W. Bush], but the bulk of the collection will be of more interest. There are catalogues galore from much of the company’s history, items from many of its promotions over the years including its ventures into sporting sponsorship, and numerous examples of Radio Shack products. You will find most of the computers, including a significant number of TRS-80s and accessories, tube-based radios and equipment from the 1950s, as well as cardboard boxes stuffed with more recent Realistic-branded items. There are even a few retail technology dead ends to be found, such as a box of :CueCat barcode readers that they evidently couldn’t give away back in the dotcom boom.

If you are interested in any of the Radio Shack lots, you have until the 3rd of July to snap up your personal piece of retail electronic history. Meanwhile if you are interested in the events that led to this moment, you can read our coverage of the retail chain’s demise.

Thanks [Mark Scott] for the tip.

Hacked Car Axle Yields Custom 90° Gearbox

Need a sturdy angle gearbox to handle power transmission for your next big project? Why not harvest a rear axle from a car and make one yourself?

When you think about it, the axle of a rear-wheel drive vehicle is really just a couple of 90° gearboxes linked together internally, and a pretty sturdy assembly that’s readily available for free or on the cheap. [Donn DIY]’s need for a gearbox to run a mower lead him to a boneyard for the raw material. The video below shows some truly impressive work with that indispensable tool of hardware hackers, the angle grinder. Not only does he amputate one of the half axles with it, he actually creates almost perfect splines on the remaining shortened shaft. Such work is usually done on a milling machine with a dividing head and an end mill, but [DonnDIY]’s junkyard approach worked great. Just goes to show how much you can accomplish with what you’ve got when you have no choice.

We’re surprised to not see any of [DonnDIY]’s projects featured here before, as he seems to have quite a body of hacks built up. We hope to feature some more of his stuff soon, but in the meantime, you can always check out some of the perils and pitfalls of automotive differentials.

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