Because Conventional Laser Harps Aren’t Dangerous Enough

September 10, 2019 by Jenny List 7 Comments

In the late 1980s, the French musician [Jean-Michel Jarre] famously toured with a laser harp. The word among teenage fans was that he had to wear special gloves to stop his hands getting burned, because 1980s teens were both impressionable and didn’t know much about lasers. In fact we’re told by a member of our community who was part of his road crew that the glove was a matter of reflectivity, so laser harps remain relatively harmless and French harpists retain their fingers. To add a bit of spice to the laser harp experience, [James Cochrane] hooked up a laser rangefinder to a Tesla coil to make an instrument with a bit more crackling energy in its performance than the [Jarre] model.

It starts with a laser tape measure modified to serve as an Arduino rangefinder, coupled to custom MIDI code to make a laser harp MIDI controller. The Tesla coil in question happens also to be a MIDI instrument, so the one can control the other with ease. The addition of an earthed chain mail glove allows it to be played in close proximity to the coil, and he rewards us with a rendition of the Star Trek theme. Tesla fun and games behind us, he then gives us a demonstration with a more conventional MIDI instrument.

We’ve had innumerable Tesla coil projects here over the years, if you’re hungry for more we suggest starting with this unusual planar PCB coil design. Meanwhile you can see the laser harp coil in the video below the break.

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MIDI Controller In A Concertina Looks Sea Shanty-Ready

August 18, 2019 by Dan Maloney 5 Comments

Did you know that the English concertina, that hand-pumped bellows instrument favored by sailors both legitimate and piratical in the Age of Sail, was invented by none other than [Sir Charles Wheatstone]? We didn’t, but [Dave Ehnebuske] knew that the venerable English gentleman was tickling the keys of his instrument nearly two decades before experimenting with the bridge circuit that would bear his name.

This, however, is not the reason [Dave] built a MIDI controller in the form of an English concertina. That has more to do with the fact that he already knows how to play one, they’re relatively easy to build, and it’s a great form factor for a MIDI controller. A real concertina has a series of reeds that vibrate as air from the hand bellows is directed over them by valves controlled by a forest of keys. [Dave]’s controller apes that form, with two wind boxes made from laser-cut plywood connected by a bellows made from cardboard, Tyvek, and nylon fabric. The keys are non-clicky Cherry MX-types that are scanned by a Bluefeather microcontroller. To provide some control over expression, [Dave] included a pressure sensor, which alters the volume of the notes played depending on how hard he pushes the bellows. The controller talks MIDI over Bluetooth, and you can hear it in action below.

We’ve seen MIDI controllers in just about everything, from a pair of skate shoes to a fidget spinner. But this is the first time we’ve seen one done up like this. Great job, [Dave]!

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Square Laser Harp Is Hip

August 17, 2019 by Kristina Panos 5 Comments

You know, we hadn’t realized how tired we were of vertical laser harps until we saw [Jonathan Bumstead]’s entry into the 2019 Hackaday Prize. It’s all well and good to imitate the design of the inspiring instrument. But the neat thing about synths is that they aren’t confined to the physics of the acoustic instruments they mimic. This project elevates the laser harp into functional sculpture territory. It’s a piece of art that produces art.

And this art harp is entirely self-contained, with built-in MIDI, amplifier, and speakers. The brains of this beauty are an Arduino Mega and an Adafruit music maker shield, which give it twenty different instrument voices. Each of the six layers has two lasers, two mirrors, and two photo-resistors mounted in the corners of the plywood skeleton. The lasers and photo-resistors are mounted back to back in opposite corners, with mirrors in the other two corners to complete the paths. [Jonathan] cleverly diffused the laser light with milky slivers of film canister plastic.

This isn’t [Jonathan]’s first optical rodeo. Previous experience taught him the importance of being able to readjust the lasers on the fly, because every time he moved it, the laser modules would go out of alignment. This time, he built kinematic mounts that let him reposition the lasers using four screws that each push a corner.

There are a lot of nice touches here, especially the instrument selector wheel. [Jonathan] explains it and the rest of the harp in a fantastic demo/build video that’s just burning a hole in the space after the break.

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MIDI Harp Looks Pretty Sharp

August 17, 2019 by Kristina Panos 9 Comments

[Julien] is one of those cool dads who shows his love with time invested rather than money spent. His daughter plays the harp, and you would not believe the price of concert harps. Even the cheap ones are several thousand USD. So naturally, he decided he would build her a MIDI concert harp from the ground up.

This plucky work in progress uses a strain gauge and an AD620 amplifier on every string to detect the tension when plucked. These amplifiers are connected to Arduinos, with an Arduino every nine strings. The Arduinos send MIDI events via USB to a Raspberry Pi, which is running the open synth platform Zynthian along with Pianoteq.

The harp is strung with guitar strings painted with silver, because he wanted capacitive touch support as well. But he scrapped that plan due to speed and reliability issues. Strain past the break to check out a brief demo video.

[Julien] used strings because he wanted to anchor the harpist in tactility. But you’re right; many if not most MIDI harps use lasers.

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Itty Bitty MIDI Piano Sings With Solenoids

August 13, 2019 by Kristina Panos 9 Comments

Toy pianos are fun to plink around on for a minute, but their small keyboards and even smaller sound make them musically uninteresting pretty quickly. [Måns Jonasson] found a way to jazz up a two-octave toy piano almost beyond recognition. All it took was thirty solenoids, a few Arduinos, a MIDI shield, and a lot of time and patience.

This particular piano’s keys use lever action to strike thin steel tines. These tines are spaced just wide enough for tiny 5V solenoids to fit over them. Once [Måns] got a single solenoid striking away via MIDI input, he began designing 3D printed holders to affix them to the soundboard.

Everything worked with all thirty solenoids in place, but the wiring was a bird’s nest of spaghetti until he upgraded to motor driver shields. Then he designed a new bracket to hold eight solenoids at once, with a channel for each pair of wires. Every eight solenoids, there’s an Arduino and a motor shield.

The resulting junior player piano sounds like someone playing wind chimes like a xylophone, or a tiny Caribbean steel drum. Check out the build video after the break.

Hate the sound of toy pianos, but dig the convenient form factor? Turn one into a synth.

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Chiptunes Via USB MIDI With The AY-3-8910

July 30, 2019 by Lewin Day 11 Comments

There are many venerable soundchips in the chiptune pantheon, of which the AY-3-8910 is perhaps one of the lesser known. Having not served on active duty for Nintendo or Commodore it’s somewhat unloved in the USA, but it made its name in a variety of arcade and pinball machines and has quite a European following due to its appearance in machines bearing the Amstrad and Sinclair names. [TheSpodShed] decided to whip up a USB MIDI interface for the chip, with the help of the Arduino Pro Micro.

The Arduino Pro Micro is a Sparkfun creation, using the ATmega32U4 microcontroller. Its USB MIDI functionality makes it a perfect candidate for such a build, and it also packs enough digital IO to run the AY-3-8910, with 13 lines required to get things going. [TheSpodShed] whipped up the project on protoboard, with only a few passives needed along with the sound chip and Arduino.

The Arduino code was written with an eye to making the most of the chip’s limited polyphony. The synth prioritises the most recent received notes, while also aiming to keep the highest and lowest of the currently requested notes still playing where possible. This gives the synth the best chance of keeping the expected bass and melody intact when playing a wide variety of MIDI content.

It’s a tidy build, and one that shows some love for a soundchip some have forgotten. Of course, it’s not the only option – we’ve also seen the SAM2695 and YM2612 given the same treatment. Video after the break.

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Weather Station Can Rock You Like A Hurricane

July 22, 2019 by Sven Gregori 5 Comments

People love to talk about the weather. It’s the perfect small talk, whether you’re trying to start a conversation or keep one going by avoiding an awkward silence. In the same fashion, weather stations are an ideal starting point for any sort of sensor-related project ideas. You get to familiarizing yourself with communication buses, ADCs, general data acquisition, and you learn a lot in figuring out how to visualize it all.

What if your weather station didn’t visualize anything? [OttoNL] is answering that question with a MIDI-generating Weather Station that uses the mood of the music to convey the condition of the elements outside.

Using an ESP8266 programmed via the Arduino IDE, [OttoNL] hooked up a light dependent resistor, a rain sensor, and the all-round workhorse BME280 for temperature, barometric pressure, and humidity to it. Reading the sensors, the ESP will generate MIDI notes that are sent to a connected synthesizer, with each sensor influencing a different aspect of the generated MIDI signals. A sadder, slow tune will play during rain and a fast upbeat one during sunshine. While it doesn’t use the ESP’s WiFi functionality at all at this point, a future version could easily retrieve some weather forecast data from the internet and add it into the mix as well.

Connect this to your alarm clock, and you can start your day off in the appropriate mood. You can even customize your breakfast toast to really immerse your morning routine in abstract weather cues.

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