Dear narccizo,
I am also working on SPO2 calculation. I have taken help of OLIMEX MODPULSE dev. tool for it.
I am also having fluke biomedical simulator. The code given very well for spo2 limits 00 to 95. when we tried to go below with modification we also succeed in it uptp 30%.
But the placement of finger is very crucial. it should be at typical point where as in real it wont be. the standard device supports very well with improper placement. for new babies we try to connect to their foot. in this case it wont work.
I suspect the AFE. which uses the in built opamps. If we can increase sensitivity by improving gain that issue can be resolved,.
But this just a try. Please suggest.
Thanks