Best surface to mount an infrared sensor?

• A. A wooden door
• B. A glass window
• C. A metal surface
• D. A solid wall

Answer: (D)

Infrared sensors rely on a stable, unobstructed view of the area and consistent temperature readings. Mounting on a solid wall provides a rigid, stationary surface that won’t warp, move, or vibrate, which helps keep the sensor’s alignment and reduces false readings. Wooden doors can shift with humidity and use, changing the aimed field of view. Glass windows can reflect or transmit IR in unpredictable ways and are often exposed to sun, causing false triggers. Metal surfaces can conduct heat and create reflections or interference that distort the sensor’s readings. So, a solid wall offers the most reliable mounting because it minimizes movement, temperature fluctuations, and optical interference.