Making Music with Clojure and Bananas

At this point, the banana piano is a pretty classic hack. The banana becomes a cheap, colorful touch sensor, which looks sort of like a piano key. The Arduino sets the pin as a low-level output, then sets the pin as an input with a pull up resistor. The time it takes for the pin to flip from a 0 to a 1 determines if the sensor is touched.

[Stian] took a new approach to the banana piano by hooking it up to Clojure and Overtone. Clojure is a dialect of Lisp which runs in the Java Virtual Machine. Overtone is a Clojure library that provides tons of utilities for music making.

Overtone acts as a client to the Supercollider synthesis server. Supercollider has been around since 1996, and provides a wide array of sound synthesis functions. Overtone simply tells Supercollider what to do, letting you easily program sounds in Clojure.

The banana piano acts as an input to a Clojure program. This program maps the banana to a musical note, then triggers a note on Overtone’s built-in piano sampler. The result is a nice piano sound played with fruit. Of course, since Overtone and Supercollider are very flexible, this could be used for something much more complex.

After the break, a video of the banana piano playing some “Swedish Jazz.”

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Recreating the THX Deep Note

THX logo

Few sounds are as recognizable as the THX Deep Note. [Batuhan] did some research, and set about recreating the sound. The original Deep Note (mp3 link) was created in 1982 by [Dr. James A. Moorer]. [Dr. Moorer] used the Audio Signal Processor (ASP) (AKA SoundDroid) to create the sound. The ASP was a complex machine to program. The Deep Note took about 20,000 lines of C code to program. The C code was compiled to about 250,000 discrete statements to command the ASP.

Only one ASP was ever built, and LucasFilm owned it. Instead of recreating the hardware, [Batuhan] used SuperCollider to recreate the sound. Just like the ASP, SuperCollider is a tool for real-time audio synthesis. The difference is that SuperCollider is open source and runs on modern computers. [Batuhan] used his research and ears to perform an analysis of the Deep Note. He created two re-creations. The first is carefully constructed to replicate the sound. The second is a Twitter worthy 140 character version. Both versions are reasonable facsimiles of the original Deep Note, though they’re not quite perfect to our ears.

[Batuhan] isn’t the only person working on recreations. Deep Note in 1KB of JavaScript can be heard at We’d love to hear other versions created by Hackaday readers!

[Via Reddit]

Making music with the Eee PC

Create Digital Music has been watching the Asus Eee PC closely. The laptop’s portable nature and low price-cheaper than a turntable-have made them desirable to both producers and performers. CDM has collected links to many people that are figuring out how to leverage the lightweight rig. [Dan Stowell] put together a tutorial for SuperCollider, the real time audio synthesis engine. The machine is good for simple text based tracker software too. On the Windows side, a lot of software, like Guitar Rig, can be enabled with just a little display driver hacking. This really makes us wonder when we’ll see the first Eee PC keytar mod.