Newsgroups: comp.robotics
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From: strohm@mksol.dseg.ti.com (john r strohm)
Subject: Re: heart pulse detector
Message-ID: <1993Oct25.142422.5612@mksol.dseg.ti.com>
Organization: Texas Instruments, Inc
References: <2a98i6$ceo@mensa.usc.edu>
Date: Mon, 25 Oct 1993 14:24:22 GMT
Lines: 19

In article <2a98i6$ceo@mensa.usc.edu> monty@mensa.usc.edu (jim montgomery) writes:
>Howdy,
>
>I wish to either purchase or make a sensor that can detect a human pulse
>and then feed that pulse into a 68332 microcontroller chip.  If anyone
>out there has some ideas or leads for me, please mail them to:

In fall of 1969, _Popular Electronics_ magazine ran a construction article
entitled something like "Build Your Own Photoplethysmograph".  This was a
pulse sensor, using a typical for the time small incandescent lamp bulb and
a cadmium sulfide (CdS) photocell.  The lamp and cell were mounted in a
plastic carrier, which assembly was strapped to a finger.  Light from the
lamp illuminated the finger, and the cell read the reflected/transmitted
light.  The amount of light passed was controlled by the blood flow.

You should have no difficulty doing something similar with a modern
high-brightness LED and a modern photodiode or phototransistor: similar
devices are in daily use in hospitals.  (They measure pulse and blood
oxygenation.  I spent a few days hooked up to one a few months ago.)
