AVR Chiptune Project Turns This Simple Code Into Music

[Mark] had seen a few examples of algorithmic music generation that takes some simple code and produces complex-sounding results. Apparently it’s possible to pipe the output of code like this directly to audio devices on a Linux box, but [Mark] decided to go a different direction. His project lets you play simple algorithms as audio using AVR microcontrollers.

Now the code work for this is very simple, but he hardware implementation is where things get interesting. Ostensibly, [Mark] didn’t have the components available to build a filter to use PWM as an audio signal. Being that he’s a ham operator, he grabbed some radio equipment he had on hand and whipped up an alternative. He’s feeding the PWM from an Arduino into the voltage controlled oscillator on a board meant for high-altitude balloon telemetry. The signal broadcast by this board is then picked up by his radio receiver, and played on some speakers.

Rube-Goldberg contraptions aside, the effect is pretty interesting, as you can hear in the latter half of the video clip which we’ve embedded after the jump.

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Star Wars Imperial March Played By Dual Floppy Drives

Although many have made some sort of music with improvised electronics, few sound as cool as this Imperial March from Star Wars played by two floppy drives. According to [Pawel], “It’s nothing new” and quite simple. This may be true as we’ve featured an Imperial March-playing floppy drive here before, but it was only one drive. Although it may not be the London Symphony Orchestra, the two drives together sound quite good!

According to him, the FDD has a fairly simple interface. To move the head, one simply needs to pull the DRVSB pin low and then activate the STEP pin on a falling edge.  This will make the head move one direction dependent on the DIR pin state. In this case, an ATMega microcontroller is moving everything. An explanation of the pins used in this hack can be found here.

Although it may look like an intimidating hack on the surface, something like this might be a neat project to try with some old hardware and an Arduino or other controller! [Pawel] did have the idea to hook up a 5 1/4″ and 8″ drive to make a full FDD orchestra, so we can’t wait to see what he comes up with! Continue reading “Star Wars Imperial March Played By Dual Floppy Drives”

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.

CV Sequencer With A TV Out

[gijs] sent in the control voltage sequencer he’s been working on that uses the TVout Arduino library to provide a graphical interface.

The sequencer doesn’t produce any sound on its own. Instead, it outputs a Control Voltage so other synths can be sequenced with [gijs]’ TVSCV. Before MIDI came around, CV was the standard to connect synthesizers and drum machines together. Even today, a lot of boutique synths have at least one jack for CV. [gijs]’ build is really interesting because of the user interface – the TVout Arduino library was used in conjunction with a tiny CRT to change values, timing and speed of the CV output. The TVSCV is able to sequence two different channels of CV at 10 bit resolution with 16 steps per bank.

From the video after the break, the TVSCV sounds like it can produce what would be the trippiest soundtrack ever conceived for an Atari or NES game. It’s a great bit of kit, especially when connected to an Atari punk console or a TR-808 and a glitch delay.

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

[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

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

[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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