DIY capacitor leakage tester nestled among neighbours all mounted underneath a shelf

DIY Capacitor Leakage Tester With A Professional Finish

January 22, 2023 by Dave Rowntree 7 Comments

[Manuel Caldeira] has built a nice electronics work area that would be the envy of many, complete with an under-shelf rail of custom-built instruments that are specific to the needs of areas of electronics that [Manuel] is involved with. The highlighted project here is a capacitor leakage tester, which is very handy for sorting through piles of old parts looking for anything still within spec, or just verifying a part on a board is the culprit you suspect it is.

The thing is, certain types of capacitors have a limited life both in operation and in storage. Usually, we’re talking about electrolytics here, where the electrolyte solution can leak out or dry out, but also the passive oxide layer on the anode plate can deteriorate if the device is left unpowered for long periods — the oxide disintegrates, and the capacitor will start to leak current. Eventually, the breakdown can be bad enough for the capacitor to conduct so well that it overheats and the result can be a surprisingly violent experience. So, if you deal with capacitors a lot, especially electrolytics, then a leakage tester is a very good instrument to own.

We like [Manuel]’s construction method here, with custom PCBs nestled inside a simple bent aluminium enclosure. No need for a top or sides, as these, are intended to bolt underneath a shelf, and butt up against their neighbor. The front panel graphics are done in a simple but very effective manner, using printable sticker sheets, with a clear adhesive over-sheet. They certainly have a professional finish, and this is definitely a construction method worth considering.

For those a little unfamiliar with this important component, why not leap into some theory with this handy dive into the simple parallel plate capacitor? Next, may we suggest a little overview of the different capacitor types and how to best make use of them?

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Some Strings Attached: Electric Tenor Guitar Built From Scratch

May 1, 2020 by Sven Gregori 4 Comments

It’s no secret that we have a soft spot for musical instruments here at Hackaday, especially for the weird and unusual ones. An instrument that definitely fits the unusual category is the four-string tenor guitar, which — as legend has it — originated back in the 1920s by frankensteining a banjo neck and a guitar body together. Despite being around for almost a century, they’re still rarely found outside some niche genres, which makes them an excellent choice when pursuing a unique sound experience. As someone looking for exactly that, [Ham-made] decided to build an electric tenor guitar entirely from scratch, and documented every step of it at great length.

Built from two random chunks of wood, a dissected single coil pickup, and a leftover piece of elk antlers, the result is even more unique than the sound experience itself. While the rather unorthodox, faceted body shape leaves no doubt that this is a handmade instrument, the real eye-catcher has to be the neck and its oddly spaced frets. Counting the frets, the math doesn’t seem to add up either, as the twelfth fret usually creates the octave, and as such should be at half the scale length (i.e. half the string’s length from the bridge at the body’s end to the nut at the neck’s end). Turns out that [Ham-made] went for a diatonic scale instead of the usual chromatic one, essentially leaving out the notes you anyway wouldn’t play in a standard Pop or Rock setup. Using an all-fifths tuning akin to cellos and mandolins, this will work nicely over all four strings.

Aesthetics are certainly a subjective matter, and [Ham-Made] is fully aware that people might feel downright offended by his creation, but as he also wants to “embrace mistakes and promote experimentation”, he encourages everyone with similar aspiration to simply go for it — and he’s certainly no stranger to unconventional instruments and recording equipment. But before the never-tiring tonewood debate sparks up, check out this scrap metal guitar.

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Rock Out With Toilet Paper Rolls

April 21, 2020 by Sven Gregori 16 Comments

Singing in the shower is such a common phenomenon, rarely anyone ever bats an eye about it. Singing in the toilet on the other hand is probably going to raise an eyebrow or two, and it’s not for nothing that the Germans euphemistically call it “stilles Örtchen”, i.e. the little silent place. But who are we to judge what you do in the privacy of your home? So if you ever felt a lack of instrumental accompaniment, or forgot to bring your guitar, [Max Björverud] has just the perfect installation for you. (Video, embedded below.)

Inspired by the way bicycle computers determine your speed, [Max] took a set of toilet paper holders, extended each roll holding part with a 3D-printed attachment housing a magnet, and installed a Hall-effect sensor to determine the rolling activity. The rolls’ sensor data is then collected with an Arduino Mega and passed on to a Raspberry Pi Zero running Pure Data, creating the actual sounds. The sensor setup is briefly shown in another video.

Before you grab your pitchforks, [Max] started this project a little while back already, long before toilet paper became an object of abysmal desire. Being an artist in the field of interactive media, this also isn’t his first project of this kind, and you can find some more of his work on his website. So why of all things did we pick this one? Well, what can we say, we definitely have a weakness for strange and unusual musical instruments. And maybe there’s potential for some collaboration here?
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Rubber Bands Can Secure Your Sanity

March 19, 2020 by Kristina Panos 4 Comments

One of the greatest joys of being a child was figuring out that rubber bands make awesome sounds when they are plucked, and that the sound is easily changed by stretching the band to different lengths. For those of us who need firsthand experience to truly understand how the world works, these types of self-discovery are a pretty great way to learn about physics.

If you’re looking to build a physical music lesson or musical physics lesson into your burgeoning home school curriculum, look no further than the junk drawer, the broom closet, and the 3D printer. [Ham-made] used to stretch his bands across an empty tissue box, but came up with a much more professional implementation based on a broom handle. Check out this fat sound!

You don’t even need to find a spare broom handle, because none of this is permanent — the headstock piece with the hooks is meant to slide up and down to create cool sounds, and the tailpiece threads on in place of the broom bristles. Inside the tailpiece is a piezo disk and a 1/4″ jack so you can plug it in to your amp stack and start an impromptu jazz group. Just keep it under 10 people, okay?

You’ll need to mic your chanteuse, so keep the physics fun going with this plastic cup microphone.

When Toothbrushes, Typewriters, And Credit Card Machines Form A Band

August 23, 2019 by Roger Cheng 5 Comments

Many everyday objects make some noise as a side effect of their day job, so some of us would hack them into music instruments that can play a song or two. It’s fun, but it’s been done. YouTube channel [Device Orchestra] goes far beyond a device buzzing out a tune – they are full fledged singing (and dancing!) performers. Watch their cover of Take on Me embedded after the break, and if you liked it head over to the channel for more.

The buzz of a stepper motor, easily commanded for varying speeds, is the easiest entry point into this world of mechanical music. They used to be quite common in computer equipment such as floppy drives, hard drives, and flatbed scanners. As those pieces of equipment become outdated and sold for cheap, it became feasible to assemble a large number of them with the Floppotron being something of a high-water mark.

After one of our more recent mentions in this area, when the mechanical sound of a floppy drive is used in the score of a motion picture, there were definite signs of fatigue in the feedback. “We’re ready for something new” so here we are without any computer peripherals! [Device Orchestra] features percussion by typewriters, vocals by toothbrushes, and choreography by credit card machines with the help of kitchen utensils. Coordinating them all is an impressive pile of wires acting as stage manager.

We love to see creativity with affordable everyday objects like this. But we also see the same concept done with equipment on the opposite end of the price spectrum such as a soothing performance of Bach using the coils of a MRI machine.

[Thanks @Bornach1 for the tip]

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Sounding A Sour Note Can Save People From A Sour Stomach (Or Worse)

September 28, 2018 by Roger Cheng 13 Comments

We’ve covered construction of novel music instruments on these pages, and we’ve covered many people tearing down scientific instruments. But today we’ve got something that managed to cross over from one world of “instrument” into another: a music instrument modified to measure a liquid’s density by listening to changes in its pitch.

This exploration started with a mbira, a mechanically simple music instrument. Its row of rigid metal tines was replaced with a single small diameter hollow metal tube. Filling the tube with different liquids would result in different sounds. Those sounds are captured by a cell phone and processed by an algorithm to calculate the difference in relative density of those liquids. Once the procedure was worked out, the concept was verified to work on a super simple instrument built out of everyday parts: a tube mounted on a piece of wood.

At this point we have something that would be a great science class demonstration, but the authors went a step further and described how this cheap sensor can be used to solve an actual problem: detecting counterfeit pharmaceuticals. Changing composition of a drug would also change its density, so a cheap way to compare densities between a questionable sample against a known good reference could be a valuable tool in parts of the world where chemistry labs are scarce.

For future development, this team invites the world to join them applying the same basic idea in other ways, making precise measurements for almost no cost. “Any physical, chemical, or biological phenomena that reproducibly alters the pitch-determining properties of a musical instrument could in principle be measured by the instrument.” We are the ideal demographic to devise new variations on this theme. Let us know what you come up with!

If you need to do quick tests before writing analysis software, audio frequency can be measured using the Google Science Journal app. We’ve seen several hacks turning a cell phone’s camera into instruments like a spectrometer or microscope, but hacks using a phone’s microphone is less common and ripe for exploration. And anyone who manages to make cool measurements while simultaneously making cool music will instantly become a serious contender in our Hackaday Prize music instrument challenge!

[via Science News]

PVC Percussion Pipe Organ Sounds Surprisingly Good!

May 25, 2014 by James Hobson 31 Comments

PVC Instrument

Using over 20′ feet of PVC pipe, a whole bunch of 2 x 4’s and a few nuts and bolts, [Jeremy] and his cousin put together a rather unique percussion pipe organ.

[Jackson], his cousin who is a musician is always looking for different ways to make music. They had a rough idea of what they wanted to do with a few sketches, but after a day of tinkering, they ended up with something completely different — but it sounds awesome.

The frame is made of a combination of 2 x 6’s and 2 x 4’s which hold the PVC tubes in place. PVC elbows and varying lengths of pipe create a wide range of rather deep bass notes. It can be played with just your hands, or even a pair of sandals for better effect. You’d be surprised how good it sounds.

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