I am not how sure this applicable this would be to a human - but there was an article in Scientific American in the spring of 1996 where they were measuring the heart beat of a roach. They attached a small magnet to the back of the roach. The roach was in small jar that was covered with a plastic wrap. On top of the plastic wrap was a Hall Effect sensor that was amplified and displayed on an oscilloscope. The beating of the heart would expand the shell of the roach making the magnet change it's distance in relationship to the Hall Effect sensor - thus changing the output of the sensor. An interesting side point was they startled the roach once and the heart stopped beating for a period of time. Their explanation was that the nervous system of the roach is so simple that it does not have the capacity to deal with making the heart beat and the "flight" syndrome of being scared. True multitasking of computing power! David V. Fansler Network Administrator TriPath Imaging, Inc. (Formerly AutoCyte, Inc) 336-222-9707 Ext. 261 dfansler@autocyte.com Now Showing! www.dv-fansler.com Updated March 31,2000 Ann's Cancer, David's Observatory, Disney World -----Original Message----- From: Patrick J [mailto:info@DATECH.SE] Sent: Saturday, May 13, 2000 11:23 PM To: PICLIST@MITVMA.MIT.EDU Subject: SV: Heart pulse I saw a VERY cool way to measure the hearbeat. When the heart beats, your weight change a little. Very very little, but it is detectable (I saw the curves live on TV) The person just steps up on the scale and as well as measuring their weight you measure the pulse ! A more common way is to send, usually red, light through one fingertip and detect light variations and get the pulse that way. Or it should be possible to use a microphone and 'listen' to the heart and detect the heartbeat/pulse >€mne: Heart pulse >Hi everyone >is there any circuit that i can use to measure, detect, heart pulse?