>>      I am working on a project to read the oxigen level in a person
>> using a pic. I'd like to know if anybody can provide any pointers in
>> the subject as far as sensors, theory, etc, is concerned. Any help will
>> be appreciated. Thanks. Vic Lopez



If you search for "pulse oximeter"  (oxymeter?) as Bob notes you will find
quite a lot of material.

They use two LEDS of two diofferent colours.
One colour light is selectvely absorbed by blood with varying levels of
oxygenation. The other colour is not affected by oxygen levels and is used
as a reference to allow for finger transmission variations. Also used on ear
lobe.

This is a real black art. There are a number of commercial machines
available and you can but the clip on sensor heads separtately. Even with a
commercial head you are in for a lot of work.
Ecen 'real" instruments produce varying results for the same conditions !!!
Hewlett Packard are a major player in this field.

Another possible method (depending on what you are trying to do) is to
measure oxygen in exhaled breath. Various cells are available to measure
oxygen content in gas and you could even look at a paramagnetic oxygen
balance(search for paramagnetic and oxygen) . Some people have reported SOME
success using zinc air batteries as a sensor but I think this would be hard
to get good results from.

RM

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