Maybe you should get your robot a new Gibson "robot guitar". I tunes and strings itself.

http://www.gibson.com/robotguitar/gallery.html

I assume you mean 'android'-(human looking)

Actually, this sounds like an interesting project. Most of the robots I've seen implemented on the internet use model airplane servos and an 8-channel controller--if you just google 'servo controller robot' you'll see lots of options. With eight channels, you can put two degrees of freedom to four fingers. I think that would be enough to make basic chords. But to control head, eyes, etc, you'll need another controller.

Also, remember, technically, its only a robot if it works autonomously, not run by a human. Many people think that a remote controlled android counts as a robot. It does not.

what were planning to do is not really a robot hand, its like a mechanism that is composed of solenoids for pressing chords at the fret board and probably a double acting solenoid to strum the guitar. may i ask, what components, materials, devices do i need for this project? what kind of motors to use, kind of controllers? any suggestions? and how much each of those cost? thanks..

I've done automation control using model airplane-style Futaba J servos like these: http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXH318&P=7

And a controller that you can program from a PC that I've used is:

http://www.seetron.com/ssc.htm

If you intend to go wireless, that's something I've not done, but the controller site has many robot links.

I think solenoids could work to depress the strings for the chords, but you'll need one for every string and at least the first five frets? That's quite a few soleniods--also where a motor-driven servo uses the most power while moving, the soleniod will consume power while depressing a string--so you'll have to have plenty of power-supply available.

I think a solenoid for strumming is probably impossible, because they only have the ability to apply large force over a very-short distance. Possibly you could strum rhythmically using a DC motor going in a circle? with something flexible to hit the strings?

Here's a link to a video of a model-airplane servo robot to give you some ideas:http://video.google.com/videoplay?docid=5125621220591283488&q=dancing+servo+robot&ei=QN4ISJaHCIaQrAKBnNWRAQ&hl=en

a ok ok.. thanks for the comment, anyway just want to ask.. the DC motor thing going in circles is not clear to me.. how will it be able to strum the guitar? any other ideas on how to do the strumming part? what if a lever like mechanism attached to if, imitating a human strumming movement drived by a stepper motor? or a dc motor with a leadscrew system to translate a linear motion? also, what title can you suggest for this topic? thanks..

Sounds like a fun project- but it wouldn't be this first. Search for "guitarbot" on Youtube, for one. As for practicality- isn't it easier to carry an iPod? ;-)

http://www.youtube.com/watch?v=tlRi77pBYNI&feature=related