How do Motion Sensors Work?

How do Motion Sensors Work?

By oeo2018 • Apr 11th 2018

There are different types of motion sensor, but they all exist for the same purpose: remote activation. With increased industrialization and automation of services, motion sensors have been incorporated into many different systems to allow electronically powered devices to be turned on without having to be watched by a person. In this article for OEO, we go into the practical ways these sensors work as well as providing you some of its uses for LED lighting.


Type of Motion Sensor


There are two main types of motion sensor. First is an active motion sensor. These send out ultrasonic waves similar to how you would find in an ultrasound to monitor a pregnancy. It is active because this is a continuous process and it is only when these ultrasonic waves are interrupted that the sensor is activated. For this reason, it is commonly used for household security alarms.


Passive motion sensors come in different forms, but one of the most common is infrared detectors. These work by sensing temperature and/or light from a body. This is usually a person or animal. Once the changes occur, they activate the light. They can detect small changes quite well, but in domestic uses they don't have a very long range. They are commonly used for front doors or stairwells in buildings. They are clever in that they can detect a person's heat, but do not turn on when the sun shines on them despite this change in warmth.


There are industrial quality motion sensors, but these tend to be on a more sophisticated system. Many of them involve actual motion detectors rather than body heat detectors which disturb the infrared through temperature.


Applications of Motion Sensors for LED Lighting


The applications are myriad for motion sensors, but we don't just mean in terms of devices they switch on. Really, as long as the circuitry is sufficient, they can turn on just about anything. What is so great is that they provide lots of unseen benefits.


One of the main benefits means when you use motions sensors for LED lighting is that you get energy efficiency in a two fold way. Firstly, the energy saving and cost effectiveness of LED lighting means you will reduce your bills and benefit the environment. Secondly, when you use a motion sensor, it will only leave the light on for when it is needed.



Rather than leaving a light on all the time or turning lights on and off repetitively (which is not good for the system), the motion sensor will turn it on only when needed. For school corridors, parking garages or apartment buildings, this allows you to save money in not using lights when there is nothing to illuminate.


Additionally, when the motion sensor turns the LED lights on, the LED bulbs will turn on instantly without the need for warming up. This is unlike metal halides and florescent bulbs which do need a time to reach the right luminosity.


Another great application for motion sensors and LED lighting is in smart cities. They can turn on in dark places which means better illumination against crime. But they will turn off again when not needed to save energy.


At OEO, our direct replacement lights include the OEO EZ LED BC-P. This is a great bulb for replacing metal halides and has an optional plug-in motion sensor to ensure you are getting all of your lighting needs met optimally.