Hi Paul,

this sounds very interesting, do you know any more details about the oxygen
saturation measurement? Perhaps wavelengths, source of coupled LEDs or
finger/ear subassemblies, anything, which would help building such a sensor?
TIA.

Josef

>  There is one more trick however.  The LED in most medical systems is
>actually two in inverse parallel, driven by an alternating voltage (with
>one or more "off" phases).  Not only does this allow rejection of
>ambient light, but the two wavelengths used are "tuned" to the
>saturation spectrum of haemoglobin and used thereby to indicate oxygen
>saturation, something usually of great concern when a patient is
>monitored.