How do PIR motion activated lights work?

Without going into the technical weeds of this topic, PIR or Passive Infrared technology includes an electronic sensor that detects motion by infrared (IR) objects or bodies within range of the sensor. That would include humans, dogs, and other animals, since we radiate heat. Note that the sensor detects a change in radiation levels, rather than looking at average IR levels.

When connected to an LED light bulb or LED tube light fixture, a PIR sensor detects a certain range of radiated heat or what is called infrared radiation. When the sensor detects a change in radiation within its tolerance levels, it will turn on the light. After motion stops, the light will turn itself off within a certain, set time period.

• Sunco Motion Activated Shop Lights are designed to turn off after 10 minutes, when detected motion (radiation levels) stop. These lights are ideal for storage areas, basements, and infrequently used hallways, among other applications.
• Sunco’s motion activated PAR38 Dusk to Dawn bulbs light up when movement is detected and turn off 25 seconds after movement ceases. These are ideal security lights for commercial and residential homes.

Also note that PIR motion activated LED bulbs should not be placed inside an enclosed fixture; it works best with open bulb design styles.

In addition, PIR sensors can be affected by extreme hot or cold weather. During intense heat, the sensor may not detect the moving heat signature from a passing person or animal due to the overall heat detected. During extreme cold weather, the sensor may be fooled into turning on with motion on a sunny day due to the variances between the cold surroundings and a passing person or animal.

If you are using these near sidewalks with frequent foot traffic, for example where a neighbor might walk a dog near your property, you can angle the light beam down and away from high traffic areas so that lights are not flashing on off unless needed on your property.

Other terms for this type of motion activation include: Pyroelectric and IR motion.