IR LED's, and the blood stream?

Hey I am in the process of trying out a circuit that will act as a portable pluse checker. I was hoping on using the IR LED's to reflect light from the clot of blood and if it bounces off (which it should) it will be picked up by a IR Detector. The whole project rests on the question if the IR light will bounce off the blood in my veins, and if it will be picked up by the detector. So i ask you....will this work?

Please keep in mind I am trying to keep the project simple, so no programming would be great!


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 You can use a red or IR LED.  Search "pulse oximeter circuit" and take a look at http://www.oximetry.org/pulseox/principles.htm.
framistan7 years ago
here is just an idea for you to try...  did you ever notice placing a FLASHLIGHT under your hand in the dark..?  The light passes through your hand.  If you want to do something like that with INFRARED.... you might try viewing the area with most any videocamera.  They will "see" the infrared that your eye cannot see.  Try aiming any remote control at your video camera and watch the viewfinder.  you can SEE the infrared LED blinking in the camera viewfinder, but cannot see it with your naked eye.  Just something you might try. 

"There are no IMPOSSIBLE PROBLEMS.... only WELL HIDDEN solutions."
TXTCLA55 (author)  framistan7 years ago
Oh yes I already knew that. When I was building the test circuit and testing it I had a digital camera pointing at it 24/7 so I could see if the LED was getting any power. Thanks anyways though!
Kiteman7 years ago
When my sons have been in hospital, they have had a single sensor clipped to their fingertip to measure both blood-oxygen and pulse.

The clip had a visible red light.

I assume, then that the sensor's processor performed complicated maths to tell both O2 and pulse from the intensity of the reflected light.
mathews7 years ago
IR is used to measure the oxygen level in the blood.

If you use two LEDs, one red and one IR, you can measure the oxygen level. You pulse the two LEDs alternately and compare the light levels.

Try resaerching Pulse Oximeter.
NachoMahma7 years ago
.  When I was in the hospital, I was told the pulse monitor on my finger used IR. Don't know if blood reflects or blocks IR, but apparently IR will work, it's just a matter of whether you place the receiver on the same side as the transmitter or the opposite side.