Two Hard Disks And One DJ Get Down With No Delay

July 29, 2012 by Brian Benchoff 15 Comments

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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MIDI Swiss Army Knife Built From An MSP430

July 18, 2012 by Brian Benchoff 4 Comments

[youtube=http://www.youtube.com/watch?v=0hvQUXcXlEg&w=470]

Hot off the heels of his web server for the TI MSP430, [Rob] shared a MIDI booster pack for the MSP430 LaunchPad, an exceedingly inexpensive and ever more capable microcontroller that is getting somewhat of a cult following.

[Rob]’s MIDI booster pack contains a MIDI in and out port as well as just about whatever MIDI manipulation apps his mind can dream up. So far, [Rob] has a MIDI arpeggiator, a harmonizer, an echo, filter, s MIDI monitor that displays incoming messages on a Nokia LCD, and a controller that interfaces with a light sensor or joystick to manipulate MIDI variables.

Back in the 80s (and 90s, and even into the aughts), a dedicated MIDI arp or harmonizer was a crazy expensive piece of kit, especially considering how simple the device is. Those dedicated rackmount boxes can now be replaced with a TI LaunchPad and [Rob]’s booster pack.

You can check out the arp and harmonizer in action after the break.

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Christmas Prep Starts Early: MIDI Control For Strings Of Lights

July 3, 2012 by Mike Szczys No comments

If you’re planning to outdo yourself with this year’s Christmas decorations now’s the time to start planning. After all, what else have you got going on since the dreadful heat is making outdoor activities a sweat-soaked misery? Take some inspiration from [Tim] who just finished prototyping a wireless MIDI controller for his strings of Christmas lights. You can just see the four spools in the distance which are lighting up as he tickles the ivories.

The wireless link is provided by a WiFi access point which uses its USB port to control the external hardware. This is a USB Bit Whacker board which in turn drives a relay board that was designed to switch mains voltages. The high voltage parts of the rig are housed in a plastic food storage container which hosts two pair of outlets to drive four channels in total. [Tim] is happy with the outcome, which he shows off in the video after the break, and hopes to expand to a total of sixteen channels for this year’s festivities.

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Open Source Synth Sounds Awesome

July 2, 2012 by Brian Benchoff 16 Comments

A little bird sent in a tip about a really cool MIDI synth. It’s called the Ambika, and it seems like just the thing to introduce a synth head to the world of soldering.

Compared to an entry-level synthesizer like the microKorg or its ilk, the Ambika is packed full of really cool features that just happen to sound awesome. In addition to the basic saw, square, and sine waves, there is also FM, and wavetable synthesis along with a noise generator, rudimentary voice synth, and a bitcrushed sawtooth wave voice. Really, the sound demos (available after the break) speak for themselves.

The hardware is based on the ATMega644p, a fairly high-powered 8-bit microprocessor notably used in the Sanguino. This synth supports up to 6 voices, each individual voice is contained on a separate circuit board attached to the motherboard.

Of course, the schematics/board files/firmware for the Ambika are freely available along with a pretty amazing set of technical notes. There’s no word on how much the Ambika will cost, but having it available as a kit should make it palatable if you don’t mind spending a Saturday holding an iron.

Tip ‘o the hat to an anon for sending this one in.

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A Sample Player You Can Slip In Your Pocket

May 29, 2012 by Mike Szczys 8 Comments

This portable sample player packs quite a punch. [Lee] wanted a nice portable way to take his samples with him, but refused to water-down the features just because it is portable. He set of goal of playing between 3-8 simultaneous notes from a large assortment of stored samples.

Sample space was the first design consideration, and it’s hard to beat the price per megabyte of an SD card. After some calculations he concluded that it is possible to pull these samples off the card quickly enough to achieve his simultaneous note goal at CD quality frequencies, but only if there is little or no latency when reading from the card. This means [Lee] needed a fast processor so he chose the LPC1769 which is an ARM Cortex-M3 processor which can run at 120 MHz.

The project box includes room for a volume knob to control the output from the in-build headphone amplifier. There’s also a rotary encoder for selecting sample sets. But we’re a bit confused on this part as the device is MIDI controlled. [Lee] is the creator of the electronic Moolodeon, which itself has MIDI out and will be used as a controller for this project.

Player Guitar Sounds Wonderful; Makes Us Drool Because Of The Complexity

May 21, 2012 by Mike Szczys 23 Comments

It becomes obvious when you listen to this player guitar that it’s not a human being playing. But the only reason for that is the unrelenting precision with which the songs are played. In addition to that accuracy, it’s interesting to note that this tune is normally played by a group of guitarists but here the machine manages to do it on one instrument. And we think it sounds fantastic!

This comes from [Vladimir Demin], a maker who previously built an automatic Bayan (like an accordion but with buttons where the keyboard is normally found). This time around it’s the six strings and many frets of a guitar that have been outfitted with one solenoid each. In the image above you can see the strumming mechanism mounted near the tone hole. Six picks are held in place, and it appears that each has two solenoids. From what we can observe in the video, one of the solenoids is used to strum the sting, the other tilts the pick mount so that there won’t be a second strumming when the pick is returned to its starting position.

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Making Old Organs More Portable With MIDI

April 24, 2012 by Brian Benchoff 3 Comments

In the 60s 70s and early 80s, roadies would lug hundreds of pounds of musical equipment around to gigs. Although the 8×10 Ampeg bass cabinet wasn’t fun in the least, the absolute worst was the Hammond organ. These behemoths of tonewheel organs sounded great, but moving them was a pain. For better or worse, portable MIDI keyboards caught up with the sound quality of these old electromechanical monsters. Everything is still not right with keyboard players; a good set of organ foot pedals is still hard to come by. To solve this problem, [Jeremy] converted his old Hammond A-100 organ pedals to MIDI giving him all the feel and aesthetics of an ancient instrument without all the heft.

To transform the ancient A-100 bass pedals into a keyboard, [Jeremy] turned to the HighlyLiquid MIDI CPU. This small board provides a few dozen pins to wire up to switches and potentiometers. A new switch assembly was built for the bass pedals using a momentary push button switch under each key. These buttons are wired up to the MIDI CPU, and everything worked out wonderfully.

Although there’s no video of the newly portable Hammond organ in action (something off Zeppelin I, [Jeremy]…) there is a great Flickr photoset of the entire build. Awesome work, [Jeremy]