Other
Countdown Library
Arduino Library implements a simple counter. Apart from using a simple counter, such as a lap counter or an encoder, the main interest of the library is to use the Callback function to release part of the code to the program main stream
Maintainer: Luis Llamas
This library is compatible with all architectures so you should be able to use it on all the Arduino boards.
To use this library, open the Library Manager in the Arduino IDE and install it from there.