WalkSX from Gijs on Vimeo.

As the Sony Walkman turns 30, many of the mobile cassette’s fans wax nostalgic. But it takes Gijs Gieskes to wire up a new Rube Goldberg-style musical instrument based on the Walkman’s simple tape playback.

Follow along carefully through the signal flow of this unusual instrument:

1. The Walkman has audio on the tape itself, sampled from a Roland TR-808 drum machine.

2. Because a compact cassette has two tracks (left and right, for stereo), one track is dedicated to the drums, another to the rim shot.

3. The rim shot track is fed as a mono audio input to an Arduino (the open-source microcontroller platform). The Arduino responds to the audio level, so each time a rim shot hit occurs, it ….

4. …sends a sequence event to the Gakken SX-150. That means that you can adjust the speed of the whole contraption by…

5. …adjusting the speed of the tape. (Bless you, analog playback!)

It takes Gijs to think that way somehow: put together, these elements are actually fairly simple, but strikingly effective. Fortunately, if this does inspire new ideas, Gijs has posted all his Arduino code, so you can check this out and try something yourself.

http://gieskes.nl/instruments/?file=walksx

A $50 synth that makes neat noises is fun. But a $50 synth that has a proper housing, audio jacks, and can be MIDI controlled — that’s a whole lot better. So readers were wowed last week as we saw the work MrBook did with his Gakken SX-150.

Now, by popular demand, MrBook shares his techniques with specs, instructions, and code. This isn’t a bad project to get started with if you’ve been thinking of doing something on these lines.

The basic ingredients and process:

• Find the connections on the synth for audio and control, using contact points on the board
• Build a simple circuit that adds MIDI input (control) and audio output – schematic on his site. It’s not a tough circuit at all — this could be fun soldering practice.
• Add the Arduino, the open source, dirt-cheap, accessible microcontroller project board, and some code MrBook has written for you.

That should be fun even for relative newcomers – provided you have basic soldering chops. If you want to get more advanced, there’s room to modify the Arduino code to do fun stuff, or, as MrBook is doing, add a standalone Arduino sequencer or the like to drive your synth in hardware alone. (While I’m still on a crusade to do OSC for stuff that talks to computers, I think MIDI should absolutely be used for what it’s good add – connecting hardware.)

You can also have some fun with the casing. (Someone needs to mod the drab colors on the Gakken, too, I think.)

If you do a project and document it, do let us know! And we’ll be watching for more from MrBook.

You can get your SX-150 kit from our good friends at MAKE. (Nope, I’m not getting any cash for saying that. Hmmm… okay, I need an affiliate account, don’t I? Make?)

SX-150 synth mod instructions, schematics and code [MrBook]

Via Collin Cunningham at MAKE, MrBook has a lovely rig with a modified Gakken SX-150, the synth kit that sells for US$50 in the States and has even been seen as a free add-in with Japanese magazines. He’s added MIDI control and a digital audio converter, and put it into a housing, which makes for a quite-playable instrument.

Really terrific work! Of course, a few thoughts:

• We need an OSC-compatible synth. (Anyone out there?)
• I love you, Live, but this looks like a perfect job for Numerology (for its modular sequencing) or Renoise (for tracking).
• Looks like more controls would make this even more self-contained.

Gakken sx-150 arduino hack number two: Adding MIDI and Audio out

If you have synth projects like this, we’d love to see them.