non-blocking code

Mastering Arduino Part 4 card (horizontal)
Mastering Arduino Part 4: Timing Without delay(), millis(), micros(), and Non-Blocking Loops
Arduino DIY Electronics
Part 4 of the Arduino Mastery Series: why delay() freezes your whole sketch, how millis() and micros() track time without blocking, and a non-blocking control panel project that blinks, dims, and times a button press all at once.