Home Improvement Skills & Specialties Electrical

Types of Motion Sensor Lights: Your Complete Guide

A closeup shot of a motion sensor light switch on the wall

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The different types of motion sensor lights are designed to detect motion and then trigger a response—either turning a light on or off without the need to touch a switch. Motion sensor light switches are installed on interior walls, ceilings, doorways, or on the exterior parts of a home or yard for added security. Learn the different types of motion sensor lights and their purposes so you can choose the right one for your needs.

How Motion Sensor Lights Work 

Motion sensor lights use a variety of different types of sensors to detect motion, then automatically turn the light on at detection. Some motion sensor lights are designed to solely turn the lights off once a person leaves the room. Some motion sensor lights may be more sensitive than others. Based on the type of motion sensor light you install, the sensitivity may be able to be adjusted through a sensor head control.

Types of Motion Sensor Lights

There are three types of motion sensor light switches. For example, garage door openers typically activate the overhead lights in the space if someone enters the space or moves inside the area. That's because the sensor notices that the speed of the returning sound waves changes—triggering the light switch thanks to a passive infrared sensor. See more about the types below.

  • Infrared: There are two types of infrared sensors—passive and active. Passive infrared (PIR) sensors are the most commonly used motion sensor devices. PIR sensors recognize infrared radiation (heat) from moving objects, people, and animals to activate a light. Active infrared sensors are more complex devices that emit and detect radiation and are often used in security systems.
  • Radio Wave: Also called microwave sensors, this type of sensor emits radio waves into a space. When the radio wave bumps into a nearby object, the frequency shift triggers an electrical signal that turns on a light.
  • Optical: An optical movement sensor detects the close-range movement and direction of an object to trigger a light to turn on or off.

Occupancy vs. Vacancy Switches

Motion sensor switches can automatically turn the lights on or off or both. Both occupancy and vacancy switches leave the lights on if they detect motion in the room, so if you're perfectly still, they might turn the lights off. However, there are some differences to note between the two.

In the case of garages and places where you expect to have your hands full, an occupancy switch is your best bet. Vacancy switches or switches that need to be turned on tend to save more energy because the occupant may want to leave the lights off or dimmed to a lower level.

Occupancy Switches

Occupancy switches turn the lights on when you enter the room; when you leave, the switch waits a preset time before turning the lights off automatically.

Vacancy Switches

Vacancy switches must be turned on manually but will turn the lights off automatically when you leave the room. If you have kids who tend to leave their bedroom lights on, then vacancy-type motion sensor switches are a good solution. You can also get motion sensor switches with a built-in dimmer, allowing you to set the desired light level manually. This switch is a helpful feature for bathrooms and bedrooms, where you might not want full brightness at night, in the morning, or when others are sleeping.

Is a Motion Sensor Light Right for You?

Of the many reasons for getting motion sensor lights, the three most significant considerations are energy conservation, theft or crime deterrent purposes, and convenience.

Save On Energy Costs

You can save on energy costs. light bulb usage, and contribute to a more eco-friendly lifestyle by installing motion sensor lights. It's very easy to forget to turn off lights, for example, in a garage or basement, and you may leave the lights on all night.

Increase Home Security

If you use floodlighting to guard your house against intruders, keeping a light on all night may not alert you to a change in the perimeter, whereas a motion sensor light turning on might get your attention. Motion sensor lighting outside the house is also handy when taking out the trash, walking the dog at night, arriving home after dark, or leaving in the morning before sunrise.

Add Convenience

For convenience's sake, motion sensor lighting will help forgetful family members who leave a room without switching off the light by handling the task. The other benefit is if your hands are full, you don't have to fumble for a light switch, or in some cases if the light switch is in an odd place or further away, you can eliminate the need to use a switch at all.

Wiring

Motion sensor switches are designed to replace any standard single-pole wall switch. Specific wiring configurations vary by product. Some switches include a neutral wire connected to power the LED, while others do not (standard switches typically do not connect to the neutral circuit wire). Be sure to check the wiring schematic that comes with your specific model of the switch to ensure you wire it correctly.

In a typical installation, the motion detector switch has three wire leads. The black lead connects to the incoming "hot" wire that supplies the power to the switch. The blue lead connects to the outgoing circuit wire connected to the light; this is called the switch leg. The green lead is the ground and links to the circuit's ground system.

Warning

Before you start any wiring work, turn off the power to the fixture at the main panel. Test the wires to make sure the current is off by using a voltage tester to test the ground wire (green), hot wire (black), and neutral wire (white).