The RPC: a stand-alone MIDI workstation


Not just another pretty enclosure, this shiny little red box is [Lauri’s] stand-alone MIDI workstation. The build uses an Arduino Mega 2560 to handle the MIDI inputs and outputs. It communicates via serial with a Raspberry Pi that acts as a sequencer and oversees all user interactions. The Pi’s SD card offers convenient storage for your work, though we wish it was easily ejectable from the front of the box and not trapped under the hood. [Lauri’s] RPC also squeezes in the necessary USB hub for the RasPi and an HDMI-to-VGA converter. As an all-in-one solution, this is a sleek little box that–once paired with some software for arpeggiators, chord harmonies, and scales–will be a handy MIDI sequencer with robust control ready to be conveniently mounted on your rack.

Now all you’ll need is something to plug in. Why not check out the custom MIDI recorder we featured last week, or the organ-to-MIDI keyboard conversion for inspiration.

[Thanks Teemu]

Tearing apart an organ and making a MIDI keyboard


What do you do if you’re in a band and have an old, dead organ lying around? Build a MIDI foot controller, of course.

After dispensing of the old organ guts, [Mark] mounted the pedals in a handsome road case and started working on the electronics. His first inclination was to mount an Arduino Pro Mini on a piece of stripboard, but after that failed decided to learn Eagle and fabricate a PCB. each key of the organ pedals are connected to a switch read by the Arduino which sends data to a Korg Microsampler over MIDI.

The swell pedal from the organ was also reused, but because the old incandescent light in the pedal was toast, this was replaced with an LED. It still works, allowing [Mark] to do volume swells on his new, fancy, MIDI foot controller.

You can check out a video of the controller below.

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LED illuminated isomorphic keyboard looks as good as it sounds

Unlike the traditional ebony and ivory found on pianos, isomorphic keyboards arrange buttons on a grid. This makes every chord the same shape, and to transpose a piece it’s simply a matter of moving your fingers a few places to the left or right. [Brett Park] sent in an isomorphic keyboard he built loaded up with LEDs, and we’re thinking it the perfect instrument for musicians looking to move up from playing their MacBook.

The body of [Brett]’s keyboard is made out of a sheet of acrylic. After drilling 64 holes for each of the clear arcade buttons, [Brett] bent the sides of his hexagonal keyboard into a very sturdy-looking enclosure.

On the hardware side, [Brett] used a 64 button Arduino shield and a Sparkfun MIDI shield. The RGB LEDs behind each button are controlled via MIDI sysex messages generated outside the instrument, making it perfect for a little bit of visual feedback from whatever soft synth you desire.

In the videos after the break, you can check out the light patterns in action along with one of [Brett]’s improvs. Notice how all the chords are the same shape, and changing the key only requires [Brett] to move his hands slightly to the side.

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Making Music With Tennis Balls and Lego

We’ve seen a lot of interesting MIDI controllers, but this one uses some unconventional materials. The World’s Coolest Keystroke, built by [Audiobody], is made from a combination of tennis balls, Lego bricks, servos, and switches.

When a tennis ball is lifted up, a Lego arm is actuated. It looks like a servo is used to move the Lego arm so it hits a switch. An Arduino is used to detect this and send a message to their computer.

They use the device to control Ableton Live and play different clips depending on which tennis ball was removed. It’s an interesting way to control sound with a tactile interface, and it looks pretty nifty.

After the break is a short video of the device in action, but [Audiobody] says that they will be releasing more information soon. We’re looking forward to seeing other interesting controllers that they have in the works.

[Via Make]

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Two hard disks and one DJ get down with no delay

Mixmaster [robelix] built a MIDI controller for DJs that uses two hard drives for scratching and cutting some wicked beats.

[robelix]’s project is called Hard DJ and was inspired by this earlier build capable of producing a droning appreciated chiptune music using the motor inside a hard drive. Instead of reading the out of phase sine waves produced when a hard drive platter is manually rotated, [robelix] used custom laser cut encoder wheels and an IR detector from old computer mice. This gives [robelix] far more resolution than would be possible by reading the drives stepper motors and allows him to scratch and cut to whatever his MC desires.

The electronics portion of the build are a little rough at this stage – just an Arduino Mega, a few buttons, and a trio of faders. [robelix] will be building a proper enclosure for his controller soon, something we can’t wait to see.

If you’d like to clone this DJ controller, all the files are up on the Git. Check out the video after the break.

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Isomorphic piano keyboard is button madness

[nikescar] sent in a link to a huge isomorphic MIDI keyboard. We might have missed it the first time around, but that doesn’t diminish such a great looking project.

According to the project page, this humongous keyboard is the work people at Louisville Soundbuilders’ efforts to clone the AXiS-64 MIDI controller. Instead of looking like a ‘normal’ piano keyboard, this isomorphic keyboard puts notes in a hexagonal pattern. This keyboard layout is very useful – fingerings for chords are the same across all keys – but these keyboard layouts are fairly rare and MIDI controllers are expensive as a result.

To make the keyboard in the video velocity sensitive, there are two layers of PCBs. The top layer uses Cherry key switches, while the bottom PCB is an array of tact switches. Measuring the time between the top and bottom key presses gives the on board microcontroller velocity information that is converted to MIDI notes. This setup has a few downsides, namely the huge amount of switches, components, and pins needed for two keyboard matrices.

The project page hasn’t been updated for a few months, so we’re pretty curious about the current status of this build. If any of the Louisville Soundbuilders have an update on this project, send it on in.

Fully fretted guitar MIDI controller

[Andy] came across this guitar midi controller project from way back and decided to send us a tip about it. The English version, translated from the original Russian, is easy to follow and documents the build process from first prototypes to the version you see above. It can connect via a standard MIDI cable and then be used to control anything you want. The only thing missing is the ability to transmit velocity data, but that’s certainly not a deal breaker.

The device has two sensory parts. The first is a set of pickups that can be seen underneath the strings near the bridge. These work like standard magnetic pickups but instead of extrapolating fret data from the pitch picked up on the string, there is a second sensor mechanism for every fret of each string. Since the strings are made of metal, it’s possible to detect which fret is depressed based on continuity sensing. Of course this means you need a conductor between every fret, and that’s why the fingerboard has been replaced with one made of printed circuit boards. All of this data is gathered, then sent to the MIDI device via a PIC 16F74 microcontroller.

If this leaves you wanting for more guitar hacks, don’t miss this one that adds addressable LEDs in between each fret.