How Motion Sensors Works in Surveillance Cameras

According to Honeywell, motion sensors located in security cameras are known as Passive Infrared (PIR) devices. These devices work by detecting motion or body heat in the area they are covering.

Temperature

Motion detectors are set to detect temperatures between a certain range; security cameras are set to a temperature range, based on the average human body temperature of 98 degrees Fahrenheit. The Gadget Shack reports the temperature range of security camera motion sensors is set on a bandwidth between 8 and 12 micrometers.

Movement

According to the Gadget Shack, a PIR motion sensor detects movement by judging a change in temperature against a cool surface and a warm surface, such as the human body. When a warm object passes before the motion sensor, the security camera is activated.

Use

As motion-sensor security cameras are activated by movement and heat they are usually placed in low traffic areas of a building, according to Honeywell. In stores a beam of light is passed in front of a door, and when the beam is broken, a security camera is activated overlooking the door.

References

• Gadget Shack: How PIR Motion Sensors Work
• Honeywell: Security Devices