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, ...
A 10k ohm potentiometer is connected to an analog input. Turning it translates into values in the range [0-1023]. An attached SSR is connected to a water heater. By turning the SSR on and off, it is ...