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Pulse oximeter

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m-bindhammerM. Bindhammer 09/15/2015 at 17:171 Comment

The current heart beat monitor works quite well, but a pulse oximeter would be better to get the pulse rate and the saturation of peripheral oxygen SpO2.

After a lot of research I found this promising reflective pulse oximeter design. The circuit outputs amongst other things directly the peak IR and red light voltages. The simple equation

is used, and S represents the value of StO2 in a calibration table.

I will use a commercially available pulse oximeter to approximate a function of the saturation of peripheral oxygen depending on S.

Redrawn and slightly modified schematic:

Next step will be to build a prototype and see how it works.

PCB layout of the prototype:

Discussions

rajs wrote 02/24/2024 at 14:34 point

Hello, I have build the same pulse oximetry circuit on proteus with photodiode (BPV10NF), I do get a signal at point out but get nothing on peak detector, could someone help why is that case?

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