The MAX30105 is an optical sensor capable of a great many things. It can sense particulate matter in the air, or pick up the blinking of an eye. Or, you can use it as a rudimentary way to measure your heart rate and blood oxygen levels. It’s by no means a medical grade tool, but this build from [Taste The Code] is still quite impressive.
This is a companion discussion topic for the original entry at https://hackaday.com/2024/03/26/this-air-particulate-sensor-can-also-check-your-pulse-rate/