On The Other Hand, It's Myoelectric
From: Electronic Design - 08/02/2007 - page 21
By: Daniel Harris

A team of engineering students from ITESO graduate school at the Universidad
Jesuita de Guadalajara in Guadalajara, Mexico entered their latest project in
Freescale Semiconductor's Black Widow $10,000 Design Challenge. The team's
myoelectric prosthetic hand not only maintains user comfort and
functionality, it also minimizes costs. 

Myoelectric prostheses measure the small (microvolt) electrical emissions
produced by muscles during contraction and relaxation. After a signal is
detected, it is amplified, filtered, and rectified to determine what action
(if any) should be applied to the prosthesis. 

According to ITESO project lead Alan Collins, the hand has four movements:
open, close, and right and left rotation. "It was made thinking [of] hand
amputees that can move their forearm muscles. The forearm muscles directly
control the four movements of the mechanical hand," he says.  

The movements are determined by four pairs of electrodes that detect the
myoelectric impulses from the forearm. The electrodes use a method that's
similar to electroencephalograms (EEGs) that measure brain activity. There
are four main signal-conditioning stages: amplification, filtering,
analog-to-digital conversion, and the motor drivers.  

Read the entire article at:
http://www.electronicdesign.com/Articles/ArticleID/16140/16140.html

Links:
ITESO: Universidad Jesuita de Guadalajara
http://www.iteso.mx

Student Designed Hand Grabs Top Award
http://www.chipdesignmag.com/display.php?articleId=1420

Myoelectric Prosthesis Wins Freescale Design Challenge
http://www.designnews.com/article/CA6456694.html

Myoelectric Hand Prosthesis Catches First Prize
http://askelizabeth.typepad.com/weblog/2007/06/myoelectric-han.html