non contact heartrate aquisition

Kernsdoug kernsdoug at
Wed Nov 18 13:29:05 EST 1998

hmm, Didier brings up an interesting idea - 
you could modulate a laser pointer and look
at the return signal - with appropriate optics,
such a thing might be able to give you a good
guess at someone's heart rate from a great

  I wonder if anyone has already done this?

Douglas Kerns
electronic sensors and instrumentation
d_kerns at
(remove the tail to get a real email address)
>From: didier at (Didier A. Depireux)
>Date: Wed, Nov 18, 1998 12:02 EST
>Message-id: <72uujd$d46$1 at>
>no-spam at wrote:
>: How can I aquire a person's heartrate without a contact device?
>In high school, I built a little device... You put your finger in it, there
>was an LED shining bright red light on your finger from above, and the
>photo-diode on the underside of your finger gave a signal that was
>modulated by the heart pulsating through the finger (given the right
>filters). Strictly speaking, you didn't have to touch anything, you just had
>to be close enough to the light source (in my days, you couldn't just buy a
>laser pointer...), and to the diode.
>These were the days!
>						Didier
>Didier A Depireux                              didier at
>Neural Systems Lab       
>Institute for Systems Research          Phone: 301-405-6557 (off)
>University of Maryland                                -6596 (lab)
>College Park MD 20742 USA                     Fax: 1-301-314-9920

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