The beating of the heart is often recorded via sound or simply with touch – but there’s also another interesting and somewhat lesser known option – light. An infrared emitter/detector pair can be used along with a programmable microcontroller, to effectively visualize the effects of the human body’s hardest-working muscle.
After checking out a few projects involving IR heart monitors, I decided to have a go at the interface myself. Seen above are the results of my first experimentation with pulse oximetry. Getting the setup up and running satisfactorily required a bit more time and tinkering than I’d expected – especially after reversing a premature mod to my emitter/detector pair. The next version I try will either use a higher output emitter (see Charles Martin’s version) or
some amplification hardware (as used in Meng Li’s sensor).