Why Wasn’t This Magnetic Cello Made In The 70’s?

September 22, 2011 by Brian Benchoff 34 Comments

[magnetovore] made himself an electronic cello. Instead of pulling a few cello samples off of an SD card, he did it the old school analog way. The finished build is really impressive and leaves us wondering why we haven’t seen anything like this before.

[magnetovore] uses a permanent magnet to play each ‘string’. A lot of details are in this post and [magnetovore]’s provisional patent (PDF warning). From what we can gather, each string is a resistive ribbon sensor connected to a voltage controlled oscillator. The output of the VCO is sent to a variable gain amplifier that is controlled by a coil of wire and the magnetic ‘bow’.

From the video (after the break), [magnetovore] already has an amazing reproduction of the cello sound. It’s a bit electronic on the lowest parts of the C string, but with a little bit of processing it could definitely pass for an acoustic instrument. We’re left wondering why we haven’t seen anything like this cello before. VCOs and VGAs were the bread and butter of the old Moogs and even the ancient ondes martenot. Ribbon controllers were being attached to electronic instruments back in the 50’s, so we’re really at a loss on why a magnetic cello is new to us. If any Hack A Day readers have seen anything like this before, leave a message in the comments.

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Roland 808 Synced To MIDI

September 20, 2011 by Brian Benchoff 8 Comments

Reading this week’s ATtiny-themed builds, [Thomas] was reminded one of his coolest builds. His midi808 project used an ATtiny2313 to sync a vintage Roland 808 drum machine to his Logic workstation.

Even though MIDI had been around for a few years when 808s were being made, the CPU in the 808 isn’t exactly up to the task of handling MIDI. Instead, the 808 used an interface known as DIN Sync that was designed to keep 808s, 707s, and 303s in time with each other. MIDI to DIN Sync boxes do did exist, but even the auxiliary equipment to use an 808 is getting hard to find.

The build takes a MIDI signal and passes it through an opto-isolator per the MIDI spec. The microcontroller reads the MIDI signal and passes it out through the DIN Sync port. The DIN Sync protocol is only 24 pulses per quarter note output with TTL voltages, and the project code is easy enough to follow. It’s a nice build for one of the greatest drum machines ever made. Listen to a track [Thomas] made with his new setup after the break.

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Building An Optigan-like Instrument

September 13, 2011 by Brian Benchoff 10 Comments

[Olli] sent in his writeup of a musical instrument he made called the Black Deck. [Olli]’s instrument was inspired [Jimi Tenor]’s photophone – a transparent disk attached to a fan and photocell.

A transparent disk is placed on the turntable [Olli] rescued during a dumpster diving expedition. A light shines though the optical disk and is picked up by phototransistors. After writing a program to generate an A minor scale onto a transparency, [Olli] connected his contraption to a stereo and heard his creation speak. To control the individual tracks (or notes) on the disk, [Olli] made a keyboard out of photoelectric switches that control which note is played.

Superficially, [Olli]’s instrument resembles an Optigan. While [Olli]’s instrument is capable of producing waveforms, the Optigan is able to reproduce sampled instruments. That being said, we think [Olli]’s Black Deck would feel comfortable next to the Optigans of Kraftwerk and Devo. Check out the YouTube demo of the Black Deck in action after the break:

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[Dino’s] JFET Guitar Preamp With Piezo Pickup

September 12, 2011 by Mike Szczys 10 Comments

This week, with a little help from a Roomba, [Dino] built a guitar pickup and preamp that sounds marvelous. A pickup takes vibrations from the guitar and turns them into an electrical signal which can then be amplified and broadcast. He grabbed a long-dead Roomba which has slowly but surely been donating its organs for his weekly projects. After plucking out a piezo element he grabbed a bag of Junction gate Field-Effect Transistors (JFET) and built a preamp circuit around one of them.

JFETs operate in much the same way as MOSFETs (which we took a look at last week). [Dino’s] design adds a few resistors and capacitors to tune the gain and decouple the circuit from the input and power rails. He epoxied the piezo element inside the guitar and connected leads between it and a jack mounted in the body. As always, he does an excellent job of explaining the concepts behind the design and outlining the build techniques that he used. We’ve embedded his video after the break.

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Broken Vintage Record Player Reborn As A Portable MP3 Cabinet

September 7, 2011 by Mike Nathan 23 Comments

old_record_player_pc_jukebox

[Julian] picked up an old record player that was sitting in somebody’s trash pile, and brought it home to see if it could be restored to working order. When he got it home he discovered that it didn’t work at all, so he and his wife decided to modernize it a bit.

In an effort to simultaneously reunite himself with his music collection and piss off audiophiles/antique collectors in the process, he gutted the radio and began rebuilding it to serve as an MP3 jukebox. Once the innards were removed, his wife refinished the cabinet and gave the front grill a new cloth cover.

An old PC was installed inside the cabinet, along with a set of relatively cheap (but better than paper cone) speakers. A pair of custom cut plexi panels were used to cover the computer, while providing space for the monitor and Apple wireless keyboard + trackpad [Julian] uses to manage the jukebox.

The refurbed record player came out looking quite nice, and although it likely raises the ire of several different groups of purists, we think it’s pretty cool.

Controlling Samplers And Sequencers With Multitouch

September 6, 2011 by Brian Benchoff 5 Comments

When we see artists like Daft Punk or Madeon working their magic in a live setting, we’re always impressed with their controllers. Sample-based artist use controllers like the Monome and Kaoss Pad a lot, but these devices are fairly expensive. Thankfully, we live in an age of multitouch displays, so [Graham Comerford] came up with his own multitouch controller that does just about anything.

The build is based on the Kivy framework and includes a Monome emulator, MIDI drum pads, mixer, and a whole bunch of other sliders and buttons. There’s no word on how [Graham]’s multitouch display was constructed, but if you’re looking to build your own gigantic audio control setup there’s a lot of info on building Microsoft Surface clones, adapting computer monitors, and spherical multitouch rigs.

We’re not sure if [Graham]’s virtual drum kit is velocity sensitive but even if it’s not, it’s an interesting bit of kit. Check out an earlier version of his setup after the break.

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Insects Turned Into Orchestra; Not Harmed But Terribly Inconvenienced

August 31, 2011 by Brian Benchoff 28 Comments

[Jochem] has always been fascinated by chaos in nature, whether it’s a swarm of ants or evolution in action in a petri dish. His insect orchestra takes the chaos in the natural world and changes it into something completely artificial. In this case, MIDI.

For the build, a light sensor was placed at the bottom of a test tube. A cricket (or grasshopper, or locust) is then put into the test tube. The test tube is then closed up with a cap that houses a LED. An Arduino reads the light sensors and then transmits the data over MIDI. The MIDI commands are picked up in Abelton Live which converts everything to audio.

[Jochem] rigged up Abelton to have the insects perform in four different modes – instrument, synthesis, samples, and drums. Definitely an improvement over the humble Mexican Jumping bean.

You can check out the insect orchestra in action after the break.

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