What Are Motion Sensor Lights, How They Work & How to Install Them

Motion sensor lights are used to illuminate a dark area and to beef up your home security. The sensor electronically turns the lights on whenever it senses movement.

Motion sensor security lights (or motion detection lights) have 2 uses:

  1. To automatically illuminate an area in order to make it easier to walk during night.
  2. To deter burglars from breaking into your home, by turning the lights on if movement is detected.

Another advantage of using a motion sensor light is that besides keeping your home safe and illuminated, it will lower your energy bill. One of the greatest features is that you can set up the motion sensor light so that it only lights up when it senses movement. There’s no need to remember to turn the outside lights off before going to bed or after leaving a room. The sensor will automatically shut the lights off after a specific period of time.

Two Types of Motion Sensor Lights: for Indoor and Outdoor

Outdoor motion sensor detection lights are used to illuminate areas around your house (such as a driveway, a shed, an alley or an area in your back yard) and indoor lights are use to provide light inside your home (such as a laundry room or a garage).

How Motion Sensor Lights Work

The motion sensor detects heat that radiates from moving objects, such as people and animals. When heat is detected, the sensor electronically turns the light on. The light will stay on for the period of time specified by you (usually between 1 and 5 minutes) and the sensor will then shut the light off, as long as there is no more movement.

Most motion detecting lights also come with a photocell, a sensor that reacts to light. The photocell is responsible for deactivating the light during daytime.

Lower cost motion sensor lights can sense movement for up to 30 feet and have a field of view of 120 to 180 degree. On the other hand, higher end light sensors can detect movement for up to 60 feet and have a field of view of 180 degree out plus 360 degree down for total detection.

Motion light sensors also operate as conventional lights. Simply push a button or flip a switch and the light will stay on, regardless of whether it senses movement or not.

Disadvantages of Using a Motion Light Sensor

The most common problem associated with motion detecting lights is false triggers. This happens when the light goes on, when it should not. Examples include the motion detector being triggered by passing bikes, cars or blowing leaves.

In order to address this issue, decrease the range of motion detection and limit the sensor’s field of view – if your specific fixture has these features. If not, you can at least narrow the field of view by applying some tape on the sensor.

Another option (which I recommend), is getting a more expensive motion light sensor (around $90). These higher end motion senor lights will not only allow you to adjusting the range of motion and the field of view, but they also have a more temperature-sensitive sensor that will drastically reduce false triggers.

How to Install A Motion Sensor Light

Each brand has different installation procedures so make sure you read the instructions for your specific light. However, there are some general rules that apply to all installations.

  1. Turn off electricity. Shut the power going to the fixture from the main panel.
  2. Replace the old electrical box with the new one, following the instructions of the manufacturer. If you don’t have an existing box, I recommend you call a licensed electrician in order to run a new electrical wire.
  3. Connect the white neutral wires, the black hot wires and the copper ground wires.
  4. Install the new fixture by screwing it into the electrical box. Optionally, you may need to seal the new fixture with caulking or silicon, in order to prevent moisture.
  5. Adjust the motion detector by pointing it at the area you want covered.
  6. Adjust other settings available (motion sensor’s distance, shutoff time, etc…)

Note: if you have a wireless motion sensor light, the installation is very easy since there’s no need to connect any wires. Simply attach the light to the wall using the screws provided.