Wood Enclosure Lends Warmth To This DIY Ribbon Microphone

We love it when someone takes an idea they’ve seen on Hackaday and runs with it, taking it in a new and different direction. That’s pretty much what we’re here for, after all, and it’s pretty gratifying to see projects like this wooden ribbon microphone come to life.

Now, we’re not completely sure that [Maya Rom├ín] was inspired by our coverage of [Frank Olson]’s homage to the RCA Model 44 studio mic rendered in walnut veneer, but we’re going to pat ourselves on the back here anyway. The interesting thing with [Maya]’s build is that she chose completely different materials and design styles for her project. Where [Frank] built as much of his mic from wood as possible, [Maya] was fine with a mixed media approach — CNC-milled plywood for the case and stand, laser-cut acrylic for the ribbon motor frame, and 3D-printed pieces here and there as needed. The woven brass cloth used as a windscreen is a nice detail; while the whole thing looks — and sounds — great, we think it would be even better with a coat of dark stain to contrast against the brass, as well as a nice glossy coat of polyurethane.

The video below shows the whole design and build process, which was a final project for [Maya]’s audio production class this semester at college. Here’s hoping that it got as good a grade as we would give it.

Continue reading “Wood Enclosure Lends Warmth To This DIY Ribbon Microphone”

Magnetic Angle Sensor Mods Make Encoder Better For Blasting

Most of the hacks we see around these parts have to do with taking existing components and cobbling them together in interesting new ways. It’s less often that we see existing components gutted and repurposed, but when it happens, like with this reimagined rotary encoder, it certainly grabs our attention.

You may recall [Chris G] from his recent laser-based Asteroids game. If not you should really check it out — the build was pretty sweet. One small problem with the build was in the controls, where the off-the-shelf rotary encoder he was using didn’t have nearly enough resolution for the job. Rather than choosing a commodity replacement part, [Chris] rolled his own from the mechanical parts of the original encoder, like the shaft and panel bushing, and an AS5048A sensor board. The magnetic angle sensor has 14 bits of resolution, and with a small neodymium ring magnet glued to the bottom of the original shaft, the modified encoder offers far greater resolution than the original contact-based encoder.

The sensor breakout board is just the right size for this job; all that [Chris] needed to do to get the two pieces together was to 3D-print a small adapter. We have to admit that when we first saw this on Hackaday.io, we failed to see what the hack was — the modified part looks pretty much like a run-of-the-mill encoder. The video below shows the design and build process with a little precision rock blasting.

Continue reading “Magnetic Angle Sensor Mods Make Encoder Better For Blasting”

Aesthetic DIY Bluetooth Speakers

DIY Bluetooth speaker projects are always a staple here at Hackady. In our latest feature of DIY audio builds, we have [Patrick’s] vinyl cylindrical speaker.

He found a pretty inexpensive Bluetooth audio amplifier on AliExpress. However, the amplifier module oddly enough had a few missing components that were critical to its operation, so he had to do a little bit of re-work. Not something you generally expect to do when you purchase a pre-made module, but he was certainly up to the task.

He noticed the board amp module was missing a battery protection circuit even though there was space on the board laid out for those components (maybe an older board revision?). To remedy this problem, he added his own battery protection circuit to prevent any unwanted catastrophes. Secondly, he noticed a lot of distortion at high volumes and figured that some added capacitance on the power supply would help fix the distortion. Luckily, that did the trick.

Finally, and not quite a mistake on the manufacturer’s part this time, but an improvement [Patrick] needed for his own personal use. He wanted the amp module’s board-level LED indicator to be visible once the enclosure was fitted around the electronics. So, he used the built-in status trigger as a digital signal for a simple transistor circuit powering a much brighter ring LED that could be mounted onto the enclosure. That way, he could utilize the firmware for triggering the board-level status indicator for his own ring LED without any software modifications to the amp module.

Now, all that was left was to construct the enclosure he had 3D-printed and fit all the electronics in their place. We’ve gotten pretty used to the always impressive aesthetics of [Patrick’s] designs, having covered a project of his before, and this build is certainly no exception. Great job!

While you’re here, take a look at some other DIY Bluetooth speaker projects on Hackaday.

Continue reading “Aesthetic DIY Bluetooth Speakers”

Magnetic Couplings Make This Lego Submarine Watertight

Although you’d be hard-pressed to tell in some areas, it’s summer in the northern hemisphere, which always seems to bring out the projects that require a swimming pool for adequate testing. The [Brick Experiment Channel]’s latest build, a submersible made almost entirely from Lego, is one such project and has us pining for weather that makes a dip sensible rather than suicidal.

The sub featured in the video below is a significant improvement over the “Sub in a Jug” approach the [Brick Experiment Channel] favored for version 1. Rather than starting with a vessel specifically designed not to hold water, the hull for this vessel is an IKEA food container, with a stout glass body and a flexible lid with silicone seals. And instead of penetrating the hull for driveshafts and attempting to seal them, this time around he built clever magnetic couplings.

The couplings transmit torque from the motors on the inside to gears and props on the outside. And where the first version used a syringe-pump ballast tank to control the depth, this one uses vertical thrusters. The flexible lid proved to be a problem with that scheme, since it tended to collapse as the depth increased, preventing the sub from surfacing. That was solved with some Lego bracing and adjustment of the lead shot ballast used to keep the sub neutrally buoyant.

This looks like a ton of summer fun, and even if you don’t have Legos galore to work with, it could easily be adapted to other materials. There are a ton of other fun [BEC] Lego builds to check out, some of which we’ve covered, including a Lego drone and a playing card shooter.

Continue reading “Magnetic Couplings Make This Lego Submarine Watertight”

Simple Demo Shows The Potential Of Magnetic Gears

We’ve probably all used gears in our projects at one time or another, and even if we’re not familiar with the engineering details, the principles of transmitting torque through meshed teeth are pretty easy to understand. Magnetic gears, though, are a little less intuitive, which is why we appreciated stumbling upon this magnetic gear drivetrain demonstration project.

[William Fraser]’s demo may be simple, but it’s a great introduction to magnetic gearing. The stator is a block of wood with twelve bolts to act as pole pieces, closely spaced in a circle around a shaft. Both ends of the shaft have rotors, one with eleven pairs of neodymium magnets arranged in a circle with alternating polarity, and a pinion on the other side of the stator with a single pair of magnets. When the pinion is spun, the magnetic flux across the pole pieces forces the rotor to revolve in the opposite direction at a 12:1 ratio.

Watching the video below, it would be easy to assume such an arrangement would only work for low torque applications, but [William] demonstrated that the system could take a significant load before clutching out. That could even be a feature for some applications. We’ve got an “Ask Hackaday” article on magnetic gears if you want to dive a little deeper and see what these interesting mechanisms are good for.

Continue reading “Simple Demo Shows The Potential Of Magnetic Gears”

Fail Of The Week: How Not To Die Of Boredom During Isolation

They say you can’t actually die from boredom, but put a billion or so people into self-isolation, and someone is bound to say, “Hold my beer and watch this.” [Daniel Reardon]’s brush with failure, in the form of getting magnets stuck up his nose while trying to invent a facial touch reminder, probably wasn’t directly life-threatening, but it does underscore the need to be especially careful these days.

The story begins with good intentions and a small stack of neodymium magnets. [Daniel]’s idea for a sensor to warn one of impending face touches was solid: a necklace with magnetic sensors and wristbands studded with magnets. Sounds reasonable enough; one can easily see a compact system that sounds an alarm when a hand subconsciously crosses into the Danger Zone while going in for a scratch. Lacking any experience in circuits, though, [Daniel] was unable to get the thing working, so he started playing with the magnets instead. One thing led to another, and magnets were soon adorning his earlobes, and then his nostrils. Unfortunately, two magnets became locked on either side of his septum, as did two others meant to neutralize the pull of the first pair. So off [Daniel] went to the emergency department for a magnetectomy.

Of course it’s easy to laugh at someone’s misfortune, especially when self-inflicted. And the now-degaussed [Daniel] seems to be a good sport about the whole thing. But the important thing here is that we all do dumb things, and hackers need to be especially careful these days. We often work with sharp, pointy, sparky, toxic, or flammable things, and if we don’t keep our wits about us, we could easily end up in an ER somewhere. Not only does that risk unnecessary exposure to COVID-19, but it also takes medical resources away from people who need it more than you do.

By all means, we should be hacking away these idle hours. Even if it’s not in support of COVID-19 solutions, continuing to do what we do is key to our mental health and well-being. But we also need to be careful, to not stretch dangerously beyond our abilities, and to remember that the safety net that’s normally there to catch us is full of holes now.

Thanks to [gir.st] for the tip — you actually were the only one to send this in.

Jigsaw Motor Uses PCB Coils For Radial Flux

Electric motors are easy to make; remember those experiments with wire-wrapped nails? But what’s easy to make is often hard to engineer, and making a motor that’s small, light, and powerful can be difficult. [Carl Bugeja] however is not one to back down from a challenge, and his tiny “jigsaw” PCB motor is the latest result of his motor-building experiments.

We’re used to seeing brushless PCB motors from [Carl], but mainly of the axial-flux variety, wherein the stator coils are arranged so their magnetic lines of force are parallel to the motor’s shaft – his tiny PCB motors are a great example of this geometry. While those can be completely printed, they’re far from optimal. So, [Carl] started looking at ways to make a radial-flux PCB motor. His design has six six-layer PCB coils soldered perpendicular to a hexagonal end plate. The end plate has traces to connect the coils in a star configuration, and together with a matching top plate, they provide support for tiny bearings. The rotor meanwhile is a 3D-printed cube with press-fit neodymium magnets. Check out the build in the video below.

Connected to an ESC, the motor works decently, but not spectacularly. [Carl] admits that more tweaking is in order, and we have little doubt he’ll keep optimizing the design. We like the look of this, and we’re keen to see it improved.

Continue reading “Jigsaw Motor Uses PCB Coils For Radial Flux”