The HW-416-B PIR sensor has a 3-pin configuration:
| Problem | Possible Cause | Solution | |---------|----------------|----------| | No detection | Sensitivity too low | Turn SENS potentiometer clockwise | | Output stays HIGH always | Trigger mode L with long delay, or sensor facing heat source | Reduce delay, relocate sensor | | False triggers | Lens dirty, near fan/vent, vibration | Clean lens, move sensor, use shielded cable | | No output after power-up | Warm-up not complete | Wait 60 seconds | | Output toggles rapidly | Retriggering mode (H) with short delay + continuous motion | Switch to L mode or increase delay | hw-416-b pir sensor datasheet
delay(100);