Detailed Description

One-GPIO presence facade - implementation. See rcwl0516.h.

Three steps per sample: track how long the raw level has been steady, promote it to the believed level once it outlasts the debounce, then extend presence for the hold past the last believed HIGH. Every elapsed-time test is an unsigned difference (now - stamp >= limit), which is exactly what makes it wrap-safe: at a millis() rollover the subtraction wraps with it and still yields the true elapsed interval.

Definition in file rcwl0516.cpp.