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 y… ...

Hang on guys…. My esp8266-03 development board should soon be produced and available. Includes a ft230x USB uart adapter, a button to jump to the bootloader and a breadboard!