The pulse oximeter needs a high resolution ADC and the Arduino ADC is useless. This pulse oximeter measures transmitted light by sweeping the LED current and measuring the time until the output of the phototransistor reaches a specific voltage. As a result, it does not require an ADC or dedicated module, and can be assembled with only cheap and general parts that will not run out of stock even in special COVID19 demand.

I explained the operation principle in detail in youtube videos.



Youtube Video List
1. Introduction
2. General Pulse Oximeter Principles
3. Circuit Operation
4. Program explanation
5. Assembling Probe
6. Assembling Controller


Download List
Clip_Rev3_3.zip Probe STL files
Case_Rev1_1.zip Case STL files
Schematic_Rev4_1.pdf Schematic
PartsList_Rev4_1.pdf Parts List
MainBoard_Rev4_1B.zip Main board gerber files which can mount Arduino Nano
MainBoard_Rev4_1A.zip Main board gerber files which can't mount Arduino Nano
ClipBoard_Rev3.zip Probe board gerber files
POM_v0_1_1.ino Pupse Oximeter basic program