
ROOM OCCUPANCY
Occupancy sensors detect motion in an effort to indicate the presence of a person and are often used to do things like automatically turn on lights when you walk into a room or adjust temperature or ventilation settings in the HVAC system.
Occupancy sensors trigger automatic responses in a building system by utilizing different technologies like infrared, ultrasonic, microwave, radar or micro-vibration patterns as stand-ins for the visual representation of a body.
PIR sensors measure heat differences with a pyroelectric sensor. Since humans radiate heat, their presence is detected with these sensors as a difference in heat from a static point, like the wall the sensor is mounted on. Environmental sensors that measure temperature, humidity and CO2 can also be used as occupancy sensors, as humans cause certain changes in those environmental measures as a result of the body’s natural emission process. Occupancy sensors that rely on ultrasonic technology send high frequency sound waves (that humans can’t hear) into an area and measure reflection patterns. When the pattern changes, the sensor considers the space occupied.
Some of the newest and most promising occupancy sensors measure the vibrations, or micro movements, that are created when a person breathes and their heart pumps blood throughout their body. These occupancy sensors are successful because they offer complete privacy and security protection, they experience limited impact from external conditions and they can be deployed in a variety of open concept indoor spaces.