Optiboot (an older version) is installed by default on the Arduino Uno and (as of 2018) official Arduino Nano boards. It can be installed on all older mega8, 168 or 328 based Arduinos. As of 2019, ...
This is a breadboard friendly breakout board for the Maxim MAX30105 reflectance, particle, and pulse ox sensor. This library should work with other MAX3010x sensors including the MAX30102, MAX30101, ...