When it comes to making music, there are really only a few ways to create the tones needed — pluck something, blow into something, or hit something. But where does that leave this dry-ice powered organ that recreates tunes with wind chimes and blocks of solid CO2?
It turns out this is firmly in the “hit something” camp, as [Leah Edwards] explains of her project. When the metal wind chime tubes come in contact with dry ice, the temperature difference sublimates the solid CO2. The puff of gas lifts the tube slightly, letting it fall back against the brick of dry ice and making a tone. The process is repeated rapidly, providing a vibrato effect while the tube is down. [Leah] used solenoids to lift the tubes and, having recently completed a stint at National Instruments, a bunch of NI gear to control them. The videos below show a few popular tunes and a little bit about the organ build. But what — no songs from Frozen?
Most projects have one or two significant aspects in which custom work or clever execution is showcased, but this Music Box Hole Punching Machine by [Josh Sheldon] and his roommate [Matt] is a delight on many levels. Not only was custom hardware made to automate punching holes in long spools of paper for feeding through a music box, but a software front end to process MIDI files means that in a way, this project is really a MIDI-to-hand-cranked-music-box converter. What a time to be alive.
The hole punch is an entirely custom-made assembly, and as [Josh] observes, making a reliable hole punch turns out to be extremely challenging. Plenty of trial and error was involved, and the project’s documentation as well as an overview video go into plenty of detail. Don’t miss the music box version of “Still Alive”, either. Both are embedded below.
What did you do in high school? Chances are it wasn’t anywhere near as cool as turning a reed organ into a MIDI device. And even if you managed to pull something like that off, did you do it by mechanically controlling all 88 keys? Didn’t think so.
A reed organ is a keyboard instrument that channels moving air over sets of tuned brass reeds to produce notes. Most are fairly complex affairs with multiple keyboards and extra controls, but the one that [Willem Hillier] scored for free looks almost the same as a piano. Even with the free instrument [Willem] is about $500 into this project. Almost half of the budget went to the solenoids and driver MOSFETs — there’s a solenoid for each key, after all. And each one required minor surgery to reduce the clicking and clacking sounds that don’t exactly contribute to the musical experience. [Willem] designed custom driver boards for the MOSFETs with 16 channels per board, and added in a couple of power supplies to feed all those hungry solenoids and the three Arduinos needed to run the show. The video below shows the organ being stress-tested with the peppy “Flight of the Bumblebee”; there’s nothing wrong with a little showing off.
In the days before semiconductor diodes, transistors, or even vacuum tubes, mechanical means were used for doing many of the same things. But there’s still plenty of fun to be had in using those mechanical means today, as [Manuel] did recently with his relay computer. This post is a walk through some circuits that used those mechanical solutions before the invention of the more electronic and less mechanical means came along.
We aren’t sure this technically qualifies as music synthesis, but what else do you call a computer playing music? In this case, the computer is a Teensy, and the music comes from a common classroom instrument: a plastic recorder. The mistaken “flute” label comes from the original project. The contraption uses solenoids to operate 3D printed “fingers” and an air pump — this is much easier with a recorder since (unlike a flute) it just needs reasonable air pressure to generate sound.
A Teensy 3.2 programmed using the Teensyduino IDE drives the solenoids. The board reads MIDI command sent over USB from a PC and translates them into the commands for this excellent driver board. It connects TIP31C transistors, along with flyback diodes, to the solenoids via a terminal strip.
On the PC, a program called Ableton sends the MIDI messages to the Teensy. MIDI message have three parts: one sets the message type and channel, another sets the velocity, and one sets the pitch. The code here only looks at the pitch.
This is one of those projects that would be a lot harder without a 3D printer. There are other ways to actuate the finger holes, but being able to make an exact-fitting bracket is very useful. Alas, we couldn’t find a video demo. If you know of one, please drop the link in the comments below.
Electromechanical solenoids are pretty cool devices. Move some current through an electromagnet and you can push a load around or pull it. If you’re MIT student [Lining Yao], you can use them to dance. [Lining] built TapBot, a re-configurable set of tap-dancing robots that are both modular and modern. She even rolled her own solenoids.
The one with the eye stalk is the bridge, and it’s connected to a computer over FTDI. The other nodes attach to the bridge and each other with small magnets that are designed to flip around freely to make the connections. These links are just physical, though. The nodes must also be connected with ribbon cables.
Each of the nodes is controlled by an ATtiny45 and has a MOSFET to drive the solenoid at 8-12 V. [Lining] snapped a small coin magnet to the end of each solenoid slug to provide a bigger surface area that acts like a tap shoe. TapBot can be programmed with one of several pre-built tap patterns, and these can be combined to make new sequences. The curtain goes up after the break.
Simple, elegant, and well executed. This solenoid engine build is everything we’ve come to love about [Matthias Wandel]’s work. If you don’t recognize his name you probably remember the name of his site: Wood Gears.
In what feels like an afternoon project he put together a solenoid engine. It translates the linear motion of a small solenoid into the circular motion of a flywheel. The only specialized part in this hack is the solenoid. It has a pretty long throw and includes a hinge pin at the end.
The rest is crafted mostly of wood — it is admirable how he uses that table saw like a surgeon uses a scalpel. The wooden components include a base, flywheel, very interesting bearing blocks, and a few mounting brackets to hold everything in just the right place. Add to this a coat hanger for the cam shaft, the internals of a terminal strip for the cam, some heavy gauge wire, and you’re in business. The latter two make up a clever electrical switch that synchronizes the drive of the solenoid with the flywheel.
It’s amusing to hear [Matthias] mention that this engine isn’t very practical. We still think the project has merit — it’s great for learning about how simple an engine can be, and for developing an intuitive appreciation for how great commercially available motors and engines actually are. Plus, if you can mimic these fabrication techniques you can build anything. Great work on this one [Matthias], another thing of beauty!