After a few months of tossing this idea around in my head I recently constructed the Multichord, a single-stringed musical instrument that uses a hard drive to vary the tension in the string. It can play a full octave of notes by applying specific tensions related to the voltage applied to the hard drive's read-write head, as produced by an array of power resistors. A musician sets the note with pairs of buttons on the end of the instruments, then plucks the string to make the note.

I have detailed the project with photos, a video, and plans and schematics below. Check out the video below and click through to the Project Page for all of the information.

Multichord Project Page

Click on any of the thumbnails below for the full-sized image

that's pretty cool! You should release some schematics. How quickly can it change the note?

If you click through to the Project Page you will see the schematics and plans. It can change the note in about a quarter of a second or less, as shown in the video.

I must admit, that was pretty gay. Needs moar distortion.

BTW is that C4 attached on the side?

Erm no, those are the 20W power resistors. They're good for high-current or higher-voltage applications like this,

You sure? Because the resemblence is uncanny:
http://www.cemetech.net/img/projects/ee/multichord/CIMG2904.JPG
http://img234.imageshack.us/img234/4639/usdetonatorc46ee.jpg

Quite sure, because if they were not power resistors, then I would be quite dead right now. Thanks though.

Is Multichord supposed to be ironic?

Not exactly. the original, non-electronic version was called the Monochord, even though technically the correct word is Monotone, so my version with the electronic tuning is called Multichord instead of Multitone.

Your project page link gives a 404 (both here and on the frontpage).

And yeah, that is an extremely misleading name. You'd need 3 of them sitting next to each other to play a chord. :p

Fixed. Whoa, I can't believe no one called me on the 404. I agree that it's misleading, but surely my justification is logical...?

I didn't get a 404 when I clicked it yesterday.

Kerm, to correct the name, all you really have to do is tack a paper plate to the center of the instrument (below the wire), but about 1/4 of the way out from the center of the plate. Then rotate the plate as desired. multichord ftw

*facepalm* OK, you have a bit of a point there, but the pun is killing me.

This reminds me of the Gibson Robot Guitars.

http://www.gibson.com/robotguitar/index.html
You select a tuning, then strum it once, and all of the strings get tuned. And there are multiple strings, so you can play chords.

Wow, and a complete bargain at only #3600! I should get one for all my friends.

You totally should.

I remember hearing the announcement when it was released thinking "why would you spend $3600 just to have an auto-tuner?"

Why would anyone buy a Gibson to begin with? I've played Gibson's before and I really didn't think it was significantly better than my Epiphone. And my roommate has the Epiphone version of a Hummingbird with one of the fullest sounds I've ever heard out of an acoustic. I've never heard a bad Gibson, but they certainly don't stand apart enough to warrant a $2000 axe.

Because they have more hand detailing than Epiphone guitars.