Ultrasonic occupancy sensors are triggered by what?

Ultrasonic occupancy sensors work by emitting ultrasonic sound waves and then measuring the reflection of those waves off of objects in their environment. When a person or object moves within the sensor’s detection range, the sound waves are interrupted, causing changes in the frequency or amplitude of the reflected waves. This change indicates motion and allows the sensor to determine that occupancy is present in the area being monitored.

While sound, light, and heat play roles in other types of sensors, they are not the primary triggers for ultrasonic sensors. Sound is used by the sensor itself for detection rather than serving as a trigger. Light sensors operate based on changes in illumination, while heat sensors detect variations in temperature. All of these options involve different mechanisms and are suited for specific applications, but only motion, as detected through the change in reflected sound waves, activates ultrasonic occupancy sensors.