First Alert Occupancy Sensors
How to Select
How to shop for occupancy sensors?
Occupancy sensors are designed to detect and record how many people are present indoors or in a certain area in order to restrict or intensify occupancy of the system that manages the operation of the lighting or other accessories. The sensors are widely used in small public areas such as elevators or public restrooms in order to turn the light off when the room is empty and they are helpful for street lights operation to keep streets lit when people are moving on them. Recently the devices of this kind are becoming very popular for office and household applications.
A variety of types and advances features of occupancy sensors that are available on the market today can embarrass the customer who is aiming to select and purchase a suitable device. This article will emphasize some important things to avoid any problems with the sensor compatibility and usage.
Occupancy sensors use one of four technologies to detect motion such as ultrasonic, infrared, audible sound or microwave technology.
Passive infrared sensor or PIR detects human movement by sensing infrared heat that is emitted by any object such as human body or an animal. The devices convert heat into electricity and are called passive because they don’t emit infrared light but receive it.
Ultrasonic sensors produce ultrasonic high frequency sound waves that are above the limits of human hearing to detect motion throughout the room or area. These sensors use ultrasonic transducers that create vibrations and convert the returned echo into electrical or mechanical energy.
Microwave sensors contain microwave receivers and generators that emit a signal and measure the frequency of the reflected waves. The sensors of this kind are less common but more sensitive and they are essential for certain applications such as automated door openers.
There are the sensors that combine both infrared and ultrasonic technologies that take advantages of the both sensor types and offer flexibility and high accuracy of detection. In addition, there are audible sound sensors that are used in industrial areas with high noise level cause by machines and equipment. In order to purchase the correct device that is suitable for certain application and satisfies all of the requirements, it is important to consider the wattage that should exceed the amount of the installed lighting, line voltage, wall, ceiling or screw-in mounting. In addition, there are single-pole sensors that are designed to control only one device and three-way sensors that can turn on the light in several places of the room simultaneously.
Occupancy sensors are the devices that won’t cost a fortune, but they can save up to 80% of the energy consumed and, therefore, amount of money to pay each month for electricity. In addition, they ensure perfect safety, security and convenience for the residents, users or office staffers.