Improved FPGA Synth

July 10, 2011 by Brian Benchoff 9 Comments

A week or so ago we featured an FPGA MIDI interface. Since then the builder has gone crazy with his FPGA and revised his code to include polyphony and PWM output, and posted a polyphony demo.

In our previous coverage of the build, the synth was monophonic, and the MIDI implementation was pretty shaky. After realizing the hard work was done, [Mich] re-wrote the MIDI interpretation module to keep 8 voices in memory. Now the synth can play 16th note arpeggios at 999bpm.

The original build used 8 pins to output the audio with an R/2R ladder for a digital to analog converter. This didn’t work well with a polyphonic synth (everything was clipped or noisy), so [Mich] moved to PWM output.

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FPGA MIDI Interface

June 28, 2011 by Jeremy Cook 11 Comments

Hacking and digital music seem to be very much related arts. This very well built hack goes through the process of creating a MIDI synthesizer using a field programmable gate array (FPGA) and several other components.

A laptop is used as the MIDI interface which runs through a filter and then to the FPGA. This translated signal then goes through a digital to analog converter and finally to the amplifier and speakers. The FPGA is especially interesting as this chip is an array of logic gates that can be programmed however one wants. In this case, the wavetable principle is used to generate sound.

Although this is no Kaossilator yet, this device is a great start and very functional. If you’ve ever wanted to build your own electronic instrument, check out this hack. Also, check out the video after the break! Continue reading “FPGA MIDI Interface” →

Archaeopteryx: A Large, Colorful MIDI Controller

June 1, 2011 by Mike Szczys 10 Comments

This is [Robert Jarvis’] new MIDI controller which he has christened the Archaeopteryx. It makes its home (quite nicely might we add) in a discarded wooden cutlery case. This provides a strong and stable base for the controls while keeping the electrical connections close at hand for any rewiring or repair work.

The interface is made up of several different input devices. The guts from two Korg Nanokontrols donated the sliders and pots. These are both USB devices and they join with a USB keyboard which has been rewired to work with the colorful push buttons. All three devices connect to a hub inside which makes the device work using just one cable connection to the computer.

There’s a lot of wiring shoved into that shallow case. But if he keeps the keyboard mapping straight we think it won’t be too hard to configure the device. We like it that [Robert] included a snapshot of the back-of-the-envelope prototyping plans he made. This kind of ‘how I got there’ information is what we’re looking for when choosing projects to feature.

Resurrecting The Optigan Disc Format

May 16, 2011 by Mike Nathan 23 Comments

optigan

The Optigan and Orchestron were a pair of electronic organs built by Mattel in the 1970s which used swappable optical discs to store instrument information. The discs can still be found today, but the organs are extremely scarce, much to [Gan’s] dismay. After researching the organs for a bit, he decided he could probably build his own MIDI-compatible interface for the audio discs.

The discs have audio waveform data printed on them, which can be read using an LED on one side of the disc and an optical transistor on another. After successfully prototyping a reader that could interpret one of the disc’s audio tracks, he constructed a device to read all of the tracks simultaneously, just like the original organs.

His makeshift turntable was constructed on top of an old record player using acrylic discs and toy car wheels to keep things steady. Once the disc is placed on the turntable, he sets his reader in place, and via some custom circuitry, he is able to play the discs using his much more modern keyboard. It sounds pretty decent as you can see in the video below, though he does admit he would like to tweak a few things to make it sound even better.

[thanks Bryan]

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Emulating A Marching Band With Wearable Instruments

May 13, 2011 by Brian Benchoff 9 Comments

[Scott] is a design and technology master’s student who just came up with The Imaginary Marching Band – virtual band instruments you can wear on your hand.

Taking inspiration from Minority Report and the NES Power Glove, the system is able to emulate 6 instruments at this point – A trumpet, trombone, tuba, snare drum, bass drum, and cymbals. The glove itself reads data from a variety of sensors and passes that onto an Arduino Uno which sends serial data back to a computer. This data is then parsed by a Serial – MIDI converter, and can then be played back through a sampler, synthesizer or piped into your sequencer of choice. Happily, [Scott] will be designing custom PCBs for his gloves to cut down on space and weight, and he’ll also be making his project open-source eventually.

[Scott] has a kickstarter page for his project, and so far he’s been on track towards getting this project funded. Check out a demo after the break.

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Adding MIDI To A Very Old Drum Machine

May 13, 2011 by Brian Benchoff 8 Comments

Long before drum machines played samples from an SD card or EPROM, drum sounds were analog – just filtered waveforms and noise. To the modern eye, these are very primitive machines, but for [Andrew], they’re the inspiration for this brilliant hack.

[Andrew] took a Roland CR-68 drum machine from 1978 and added MIDI input with the help of a PIC microcontroller. Not wanting to modify the look of the machine, [Andrew] programmed the PIC to watch the START/STOP button when the the unit is powered on. If the button is held down, the PIC enters it’s programming mode, where the sounds from the CR-68 can be mapped to an individual note on a MIDI controller. There’s no mention if the TRIGGER IN is queried by the PIC to modify the tempo of the preset patterns, but we assume that would be a relatively trivial implementation. Still, very impressive for a machine made 4 years before MIDI.

We love [Andrew]’s work, and we’re happy for any future owner that he documented how to use his device (and cleverly taped that to the bottom of the drum machine). It’s very nice to see old drum machines being used for more than doorstops after their samples have been recorded. Check out the video of [Andrew]’s walk through after the break.

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Adding Remote Touch Control To The Kaoss Pad

May 2, 2011 by Mike Nathan 8 Comments

touchosc_kaoss

[Munki] enjoys using his Kaoss Pad MIDI controller to add a new dimension to his music while playing guitar. The only thing that bothers him about the Kaoss Pad interface is that it can be difficult to trigger or alter effects in the middle of a bitchin’ guitar solo. He started looking around to see if there was a way to control the Kaoss Pad wirelessly via a touchscreen and found that with a little tweaking, his iPhone was a perfect candidate for the job.

He grabbed a copy of TouchOSC from the AppStore and configured it to communicate with his computer. After building an interface for his iPhone, he taped it to his guitar and gave it a try. Everything seemed to work pretty well, but he didn’t stop there – he also wanted to control Ableton Live and Max MSP from his iPhone. It took a bit of research and some tinkering with the Live API, but he eventually got everything working together nicely as you can see in the video below.

If you are interested in trying this out yourself, he has several useful links throughout his article, and he has made his TouchOSC/Max MSP patch available for download as well.

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