Music Player for the Ability-Impaired

Most of the hacks we come across here at Hackaday don’t require much more than being “cool” to get our attention. But, every so often we find something that goes a step beyond that and does something truly good for the world. This is one such project, and its goal couldn’t be anymore altruistic: to allow the elderly to enjoy music, even when their declining vision and motor skills make traditional devices difficult to use.

It’s hard to overstate how important music is to people; there are few forms of art more emotionally effective. So, it was a major loss when an elderly relative of [DusteD] was no longer able to operate their CD player. Luckily, [DusteD] was there with an ingenious solution that uses RFID cards to play music from an always-on Raspberry Pi.

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Raspberry Pi Chiptune Player Rocks a Sound Chip from the 80’s

Sometimes it’s worth doing something in an inefficient way. For example, it might be worth it in order to learn something new, or just to use a particular part. [Deater] did just that with the Raspberry Pi AY-3-8910 Chiptune Player (with LED visualizers!)

The venerable General Instrument AY-3-8910 series sound chips were common in older hardware like home computers and game consoles as well as sound cards for the Apple II family. They were capable of generating three channels of square waves with various effects. Developers eventually squeezed every little bit of performance out with clever hacks. The Raspberry Pi has more than enough power to do all this in software, but as [Deater] puts it, it’s far more interesting to use an actual AY-3-8910 from the 80’s. Some LED bar graphs and matrices round out the whole system.

All the code for the Raspberry Pi AY-3-8910 chiptune player can be found on [deater]’s github repository for the project. A video of the player banging out some sounds is embedded after the break.

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Bare-bones Musical Tesla Coil is Tiny and Tinny

We’ve seen musical Tesla coils aplenty on these pages before, and we’ll be the first to point out that [Kedar Nimbalkar]’s musical high-voltage rig doesn’t quite qualify as a Tesla coil. But it’s dirt cheap, and might make a pretty cool rainy-afternoon-with-the-kids project.

Chances are good you have the parts needed for this build lying around the house. All that’s needed is an audio power amplifier and a high-voltage source. [Kedar] used a Class D amp board and a 3V to 7kV high-voltage module sourced from eBay for a couple of bucks; if you really want to go cheap, tear down that defunct electronic fly swatter gathering dust on top of your fridge and harvest the high-voltage module inside. The output of the amp feeds the high-voltage module, the HV leads are placed close together to get an arc, and the glorious high-fidelity sound will wash over you. Or not – sounds pretty awful to us. Still, it looks like a fast, fun build.

If this project gets you in the mood to go the full Tesla, check out this coil big enough to produce 12-foot arcs, or even this musical Tesla hat.

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An Organ Made from Back-Driven Steppers

[Josh] wrote in to tell us about an experimental instrument he’s been working on for a couple of months. We’re glad he did, because it’s a really cool project. It’s an organ that uses the principle of back-drive—applying torque to the output shaft of a motor—to create sounds.  [Josh] is back-driving four octaves worth of stepper motors with spinning wooden disks, and this generates alternating current. At the right speeds, the resulting sinusoidal waveform falls within the range of human hearing and can be amplified for maximum musical enjoyment.

[Josh] built this organ from the ground up, including the keys which are made from oak and walnut. Each of the forty-nine stepper motors has a corresponding wooden disk. The larger the wooden disk in the stack, the higher the resulting pitch. [Josh] says that if he built it for a full 88 keys, the highest note’s disk would be sixteen feet in diameter.

This stack of disks is driven independently by a separate DC motor, and the speed determines the key it will play in. When [Josh] plays a note, that note’s lever is actuated and its stepper motor makes contact with its disk in the stack. When they meet, the motor is back-driven by the spinning disk. In other words, they work in concert to produce some cool, eerie sounds.

Here’s a somewhat similar sort of build made from lasers and fans, if you consider that both instruments create music from objects that weren’t built to do so. Watch [Josh] play his stepper organ after the break. He has several build videos on his YT channel, and we’ve also embedded the one that covers the motor, power, and electronics part of the build.

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Keytar Made Out Of A Scanner To Make Even the 80s Jealous

Do any of you stay awake at night agonizing over how the keytar could get even cooler? The 80s are over, so we know none of us do. Yet here we are, [James Cochrane] has gone out and turned a HP ScanJet Keytar for no apparent reason other than he thought it’d be cool. Don’t bring the 80’s back [James], the world is still recovering from the last time.

Kidding aside (except for the part of not bringing the 80s back), the keytar build is simple, but pretty cool. [James] took an Arduino, a MIDI interface, and a stepper motor driver and integrated it into some of the scanner’s original features. The travel that used to run the optics back and forth now produce the sound; the case of the scanner provides the resonance. He uses a sensor to detect when he’s at the end of the scanner’s travel and it instantly reverses to avoid collision.

A off-the-shelf MIDI keyboard acts as the input for the instrument. As you can hear in the video after the break; it’s not the worst sounding instrument in this age of digital music. As a bonus, he has an additional tutorial on making any stepper motor a MIDI device at the end of the video.

If you don’t have an HP ScanJet lying around, but you are up to your ears in surplus Commodore 64s, we’ve got another build you should check out.

Electrostatic Loudspeakers: High End HiFi You Can Build Yourself

If you have an interest in audio there are plenty of opportunities for home construction of hi-fi equipment. You can make yourself an amplifier which will be as good as any available commercially, and plenty of the sources you might plug into it can also come into being on your bench.

There will always be some pieces of hi-fi equipment which while not impossible to make will be very difficult for you to replicate yourself. Either their complexity will render construction too difficult as might be the case with for example a CD player, or as with a moving-coil loudspeaker the quality you could reasonably achieve would struggle match that of the commercial equivalent. It never ceases to astound us what our community of hackers and makers can achieve, but the resources, economies of scale, and engineering expertise available to a large hi-fi manufacturer load the dice in their favour in those cases.

The subject of this article is a piece of extreme high-end esoteric hi-fi that you can replicate yourself, indeed you start on a level playing field with the manufacturers because the engineering challenges involved are the same for them as they are for you. Electrostatic loudspeakers work by the attraction and repulsion of a thin conductive film in an electric field rather than the magnetic attraction and repulsion you’ll find in a moving-coil loudspeaker, and the resulting very low mass driver should be free of undesirable resonances and capable of a significantly lower distortion and flatter frequency response than its magnetic sibling.
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Three Arduinos, Sixteen Square Waves

[Folkert van Heusden] sent us in his diabolical MIDI device. Ardio is a MIDI synthesizer of sorts, playing up to sixteen channels of square waves, each on its separate Arduino output pin, and mixed down to stereo with a bunch of resistors. It only plays square waves, and they don’t seem to be entirely in tune, but it makes a heck of a racket and makes use of an interesting architecture.

Ardio is made up of three separate el cheapo Arduino Minis, because…why not?! One Arduino handles the incoming MIDI data and sends note requests out to the other modules over I2C. The voice modules receive commands — play this frequency on that pin — and take care of the sound generation.

None of the chips are heavily loaded, and everything seems to run smoothly, despite the amount of data that’s coming in. As evidence, go download [Folkert]’s rendition of Abba’s classic “Chiquitita” in delicious sixteen-voice “harmony”. It’s a fun exercise in using what’s cheap and easy to get something done.