Introduction
Moving curtains or blinds near a window can cause PIR sensors to false-trigger. The moving fabric creates changing IR patterns that mimic human motion.
Why It Happens
Curtains move in the wind from an open window or HVAC vent. As they move, they:
- Block and unblock IR from outside.
- Create moving shadows.
- May have temperature differences if near a radiator or window.
Symptoms
- False triggers when windows are open or wind is blowing.
- Triggers correlated with curtain movement.
Solutions
1. Reposition Sensor
Move the sensor so it doesn’t “see” the curtains. Aim away from windows.
2. Secure Curtains
Use curtain weights or tiebacks to prevent movement.
3. Close Windows or Use Draft Stoppers
Reduce airflow that moves curtains.
4. Use a Different Lens
A curtain lens (long-range narrow) may help if the problem is at a specific area.
5. Adjust Sensitivity
Lower sensitivity may make the sensor ignore the smaller signals from curtains.
6. Use a Pet-Immune Sensor
Pet-immune sensors are designed to ignore small movements; they may help with curtains.
Conclusion
Curtain movement is a common but solvable problem. Repositioning the sensor is usually the easiest fix.