🚀 go-pugleaf

In article <1992Apr16.174641.25906@intelhf.hf.intel.com> dcovell@pcocd2.intel.com (David Covell) writes:
>I'm interested in experimenting with the detection and digitizing of the
>voltages involved with human muscle activity. I intend to use the electrodes
>they use for EEG testing, placing them over certain facial muscles.
>I don't know what sort of voltages I'll see, but I assume they'll be quite
>low and I'll need to use a low-noise op amp before I do my A/D conversion.
>Anyone out there have a good estimate of the levels I'll see?

For my senior design project ("A Myoelectrically Controlled Prosthetic
Arm"), I observed surface EMG signals with typical ranges of ~3 uV to 1mV
and ~20Hz to 1.5kHz.  Of course these were generated from the biceps and
triceps and would therefore be larger in amplitude than facial muscles.  I
also used silver-silver chloride electrodes (disposable surface types com-
monly used with ECG machines). You'll need to use a good instrumentation
amp with filtering and rectification to get workable signal levels.

Books to look into: 
_Design of Microcomputer-Based Medical Instrumentation_, edited by John
Webster and Willis J. Tompkins, Prentice-Hall, Inc., 1978.

_Medical Instrumentation: Application and Design_, edited by John Webster,
Houghton Mifflin Company, 1981.

_Electromyography for Experimentalists_, by Gerald E. Loeb and C. Gans, The
University of Chicago Press, 1986.


don't shock yourself.
greg

gkwan@balboa.eng.uci.edu