Timing: delay(), millis(), micros()
Blocking and non-blocking ways to measure and wait.
- delay(ms) — pauses everything.
- delayMicroseconds(us) — short precise pauses (sensor pulses).
- millis() — milliseconds since start, unsigned long, wraps after ~49.7 days.
- micros() — microseconds since start, wraps after ~71 minutes.
Compare elapsed time with subtraction: if (millis() - start >= 1000) …