The Hard Drive MIDI Controller

[shantea] builds MIDI controllers, and after a successful first endeavor with a matrix of buttons and knobs, he decided to branch out to something a little bit cooler. It’s called Ceylon, and it’s effectively a turntable controller built from an old hard drive.

As a contrast to the first MIDI controller, this would be a stripped-down build, with just three faders, LEDs for eye candy, a pair of pots for gain control, and a hard disk surrounded by six anti-vandal buttons. The hard disk is the star of the show, acting as a rotary encoder.

When manually spun, the hard disk generates a few phases of sinusoidal waves. The faster you spin it, the higher the amplitude and frequency. These signals are far too weak to be sampled directly by a microcontroller, and for digital control – as in, MIDI – you don’t need to read the analog signals anyway. These signals were turned digital with the help of an LM339 quad comparator. With two of these comparators and signals out of the hard disk that are 90 degrees out of phase, quadrature encoding is pretty easy.

The software for this MIDI controller is based on the OpenDeck Platform, a neat system that allows anyone to create their own MIDI controllers and devices.  It’s also a great looking board that seems to perform well. Video below.

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A Custom Control Surface for Audio/Video Editing

Control surfaces (input devices with sliders, encoders, buttons, etc) are often used in audio and video editing, where they provide an easy way to control editing software. Unfortunately even small control surfaces are fairly expensive. To avoid shelling out for a commercial control surface, [Victor] developed his own custom control surface that sends standard MIDI commands which can be interpreted by nearly any DAW software.

[Victor]’s control surface includes several buttons, a display, and a rotary encoder. His firmware sends MIDI commands whenever a button is pressed or the rotary encoder is turned. [Victor] plans on adding menu functionality to the currently unused LCD display which will allow the user to change the scrubbing speed and other various settings.

One advantage of making your own control surface is that you can customize it to your own needs. [Victor] has posted a model of his 3d-printed enclosure and his source code on the project page so you can easily modify his design with any button configuration you might want.

The 128 Button, 6 Axis, 17 Slider, 4 POV Hat Switch Joystick Controller


[Paul Stoffregen], creator of the Teensy series of dev boards, previously implemented a six-axis joystick for Teensyduino, the Arduino library for the Teensy. He had originally tried 8 axes, but a few problems cropped up, deadlines approached, and he left it as is. A few recent projects gave him some insight into how to implement a joystick with more than six axes as a USB HID device, so he started looking at how to read an improbable amount of pots and buttons for a USB joystick.

So far, the biggest problem is figuring out what software can actually use an HID joystick with this many controls. The answer to that question is none. The Linux-based jstest-gtk is able to read 6+17 pots, the four hat switches, but only 64 of the 128 buttons. A user on the Teensy forums, [Pointy], has been working on his own joystick test app that works on Linux Windows, but testing the joystick on Windows is an exercise in futility for reasons no one can figure out.

As for why anyone would want a six-axis, 17-slider, 128-button joystick, think about this: with this much control, it would be relatively simple to build the MIDI controller to end all MIDI controllers, or a cockpit simulator for everything from a C172, 737, to a Kerbal interplanetary cruiser. That’s an impressive amount of control, and all from a $20 Teensy dev board.

Further testing of this Teensy joystick is desperately needed, so if you’re able to help out drop a note in the forum thread.

FlightDeck: A “Touchless” MIDI Controller


[Edward] wanted a different way to modulate notes on his MIDI controller, so he decided to go touchless. Inspired by the pressure-sensing modulation on his Edirol keyboard, [Edward] aligned eight sensors into a row of playable notes and used infrared to sense the distance of a player’s hand from the keys. He also included some function buttons to cycle through 10 octaves and RGB LEDs beneath the table that perform alongside the music.

He chose SHARP GP2D120 sensors (direct link to datasheet) for their low threshold, which allowed the board to detect distance close to the sensor. Each is mounted onto a sheet of frosted acrylic along with its own “hold note” button and an LED to indicate the key is playing. The lower panel houses an Arduino Mega that drives the system along with an RGB LED strip and its driver board. [Edward] used Maxuino and OSC-Route to interface the Mega to a Max/MSP patch which runs the show.

Learn more about the FlightDeck’s features in a video demonstration of the controller and the software after the break, then check out some other MIDI hacks like this organ pedal or the Arduino-driven MIDI sequencer.

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Open Hardware Summit 2013 – Part 1: Demos

Open Hardware Summit 2013

The 2013 Open Hardware Summit took place on September 6th at MIT. There was a wide array of demos and talks covering Open Hardware methodologies and projects. After the break I’ll be covering the demo area of the conference, and sharing some of my favorite demos.

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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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