Interfacing An Old Engine Cowl Flaps Indicator To USB

November 29, 2022 by 9 Comments

[Glen Akins] had a WW2-era aircraft engine cowl flap indicator lying around (as you do) and thought it would make a jolly fine USB-attached indicator. The model in question is a General Electric model 8DJ4PBV DC Selsyn, which was intended for four-engined aircraft. For those not familiar with the purpose [Glen] explains in his detailed writeup, that piston-engine aircraft of that era were air-cooled, and during conditions of maximum engine power — such as during take-off — flaps on the side of the engine cowling could be opened to admit additional cooling airflow. These indicator dials were connected to a sender unit on each of the flap actuators, providing the pilots an indication of the flaps’ positions. Continue reading “Interfacing An Old Engine Cowl Flaps Indicator To USB” →

This Electric Outboard Conversion Makes For A Quiet Day On The Water

November 29, 2022 by 21 Comments

Nothing beats a day on the lake in a little boat with an outboard motor putt-putting along behind you. It’s great fun, if perhaps a little noisy with all that putting going on. And maybe that oily sheen on the water in your wake is not so nice. it could be that the fish are a little annoyed with your putting, too. Come to think of it, outboard motors are a bit of a problem.

Fortunately there’s a better way, like converting an old outboard motor to electric. It comes to us by way of [Anton], who happened upon the perfect donor platform — a 5-hp outboard by Crescent, sporting a glorious 1970s color scheme and a motor housing shell perfect for modding. He started by ripping the old engine and drivetrain out of the housing to make room for the BLDC motor and its driver. The motor was a project in itself; [Anton] rewound the original stator with much thicker wire and changed the coil configuration to milk as much torque as possible out of it. What started as a 180-kv motor ended up at 77 kv with much more copper and new Hall sensors for the controller. He also put a ton of effort into waterproofing the motor with epoxy resin. With a 3D-printed prop and a streamlined fairing, the new motor looks quite at home on the outboard. In fact, the whole thing barely looks customized at all — the speed control is even right on the tiller where you’d expect it.

The video below shows the build and a test run, plus an analysis of the problems encountered, chief of which is water intrusion. But as [Anton] rightly points out, that’s easily solved by reusing the original driveshaft and mounting the motor above the waterline, like this. Still, we like the look of this, and the idea of knocking around on the water nearly silently seems wonderful.

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Aesthetic PCB Design Tips For Improved Functionality

November 29, 2022 by 9 Comments

Those of us hardware types that spend a lot of time designing PCBs will often look at other peoples’ designs with interest, and in some cases, considerable admiration. Some of their boards just look so good. But are aesthetics important? After all, for most products, the delicate electronic components on that PCB are tucked safely inside a protective enclosure. But, as [Phil’s Lab] explains, aesthetic PCB designs can lead to functional improvements, such that better-looking designs are also better performing, in terms of manufacturability (and therefore yield), electromagnetic compatibility (EMC), and several other factors that can be important.

First off, making a PCB easy to read and using sane placement of components and connections will speed up debugging by reducing errors. Keeping a consistent and not too-tight placement grid can give the pick and place machine an easier task, and reduce solder issues during reflow. But there are also more serious concerns, such as the enforcement of design partitionings — such as keeping analog circuits together and away from noisy power and digital areas — which can make the difference between functioning within specification, and failure.

The video goes into a few other interesting tips, one highlight is using a ground-tied PCB perimeter zone, with wavelength-of-interest via stitching. This will reduce EMC side emissions from the power plane, but also if you select an appropriate surface finish, and keep the solder mask open, you’ve got a free, full perimeter contact to ground your scope probe. Oh, and it looks good too.

Hackaday is no stranger to beautiful artistic PCBs, like the work of [Saar Drimer] and many others. But if one PCB doesn’t cut it for your needs, there’s always the ‘Oreo’ construction to consider.

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Weird Energy Storage Solutions Could Help The Grid Go Renewable

November 29, 2022 by 122 Comments

We’re all familiar with batteries. Whether we’re talking about disposable AAs in the TV remote, or giant facilities full of rechargeable cells to store power for the grid, they’re a part of our daily lives and well understood.

However, new technologies for storing energy are on the horizon for grid storage purposes, and they’re very different from the regular batteries we’re used to. These technologies are key to making the most out of renewable energy sources like solar and wind power that aren’t available all the time. Let’s take a look at some of these ideas, and how they radically change what we think of as a “battery.”

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Standing Desk With A Clever Flair

November 29, 2022 by 27 Comments

Standing desks (also known as sit-stand desks) are somewhat polarizing. The height is adjustable, but the idea is that you move between sitting and standing while you work. Hundreds of manufacturers are out there, but they’re all the same. Two metal legs that extend and one or more motors to move the legs up and down. [JAR Made] tried to make something slightly different for their standing desk with an extending curved surface.

The build started with some gorgeous alder that was milled into square with a track saw and a planer — no jointer was required. However, he wanted long boards and was debating how to butt join the pieces together and decided on pocket holes with dowels to try and clamp the boards together while the glue dried. The resulting product was one that [JAR Made] was unhappy with. He pivoted on his feet by switching Baltic birch plywood for the main desk surface. Which was bent using a kerf-cutting technique (though just using a track saw rather than a CNC bit).

Here is where you can see him learn from his earlier mistakes. He routed a half lap in the plywood for the butt joint to give it more strength and devised a clever clamping mechanism using CA glue and painter’s tape to get good clamping pressure. The alder from earlier came in use to serve as a front edge for the plywood and a groove to hold the sliding piece of plywood that extends and retracts as the desk goes up and down.

Regular old standing desk legs screw into the underside of the desk and allow it to move up and down. Overall, it’s a wonderful build of a gorgeous desk. We love seeing people make mistakes and then pivot and learn from them. Perhaps the next step is to automate the desk to move on its own.

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VR Sickness: A New, Old Problem

November 29, 2022 by 56 Comments

Have you ever experienced dizziness, vertigo, or nausea while in a virtual reality experience? That’s VR sickness, and it’s a form of motion sickness. It is not a completely solved problem, and it affects people differently, but it all comes from the same root cause, and there are better and worse ways of dealing with it.

If you’ve experienced a sudden onset of VR sickness, it was most likely triggered by flying, sliding, or some other kind of movement in VR that caused a strong and sudden feeling of vertigo or dizziness. Or perhaps it was not sudden, and was more like a vague unease that crept up, leaving you nauseated and unwell.

Just like car sickness or sea sickness, people are differently sensitive. But the reason it happens is not a mystery; it all comes down to how the human body interprets and reacts to a particular kind of sensory mismatch.

Why Does It Happen?

The human body’s vestibular system is responsible for our sense of balance. It is in turn responsible for many boring, but important, tasks such as not falling over. To fulfill this responsibility, the brain interprets a mix of sensory information and uses it to build a sense of the body, its movements, and how it fits in to the world around it.

These sensory inputs come from the inner ear, the body, and the eyes. Usually these inputs are in agreement, or they disagree so politely that the brain can confidently make a ruling and carry on without bothering anyone. But what if there is a nontrivial conflict between those inputs, and the brain cannot make sense of whether it is moving or not? For example, if the eyes say the body is moving, but the joints and muscles and inner ear disagree? The result of that kind of conflict is to feel sick.

Common symptoms are dizziness, nausea, sweating, headache, and vomiting. These messy symptoms are purposeful, for the human body’s response to this particular kind of sensory mismatch is to assume it has ingested something poisonous, and go into a failure mode of “throw up, go lie down”. This is what is happening — to a greater or lesser degree — by those experiencing VR sickness.

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DIY Self-Assembling 4D Printing

November 29, 2022 by 5 Comments

A 4D printed object is like a 3D printed object, but it changes shape or self-assembles when its environment changes. [Teaching Tech] has been reading about this technology and decided to try to replicate it using his conventional 3D printer.

His attempts to make a joint that changes when submerged in the water looked at several options: material that can absorb water, material that expands with temperature, and — the selected option — a dissolvable locking mechanism. Essentially, a hinge is held open by a water-soluble lock. When water dissolves the lock, the hinge can spring to its natural position.

Like most experiments, this one had a few false starts. But you always learn something each time. The final design had a TPU hinge and spring with PLA structural beams. The TPU required flat printing, so various pieces have to be rotatable so they can be placed in their final orientation after printing.

Usually, multi-material setups are for printing different colors of the same kind of plastic, it’s possible to use different plastics, but it can be tricky. As a compromise, [Teaching Tech] did one print using PLA and TPU, but printed the PVA locks in a separate pass and installed them on the print at the end. The first finished 4D print wasn’t entirely successful. The hot water slowly dissolved the PVA, but it also deformed the PLA. A redesign of the lock made a big difference.

We aren’t sure this is practical yet, but we are sure someone has a need for this technique and it could be made very practical with a little work. The last time we saw 4D printing, there were magnets involved. We think this is an exciting time where people aren’t just trying to get conventional printing to work well, but are pushing the envelope with new techniques like conical slicing, for example.

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