What Is a Motion Sensor?
A Motion Sensor is an electronic device that detects movement within a selected area and signals a lighting control, alarm, or other connected system. Common sensors use changes in infrared energy, microwave signals, or both to identify motion. In security lighting, the sensor activates a light when movement meets its detection settings.
Quick Facts About Motion Sensor
Category
Lighting control device
Used for
Automatic security lighting
Common confusion
Often confused with a photocell
Also called
Occupancy Sensor, Motion detector
Often discussed with
Security Lighting Installation, Outdoor Lighting Installation
Key Takeaways About Motion Sensor
- Detection technology differs from the light or alarm it controls.
- Placement affects coverage, false triggers, and lighting response.
- A motion sensor is not the same as a photocell.
How Motion Sensor Works
Motion Sensor operation begins when the device monitors a defined area for changes that indicate movement. Passive infrared sensors notice changes in heat patterns, while microwave sensors send and receive radio signals to detect movement. Some equipment combines both methods to reduce unwanted activation.
Related glossary terms: Photocell.
The sensor sends a control signal after movement matches its sensitivity and coverage settings. A connected light then turns on through the control circuit. Aiming, mounting height, nearby heat sources, and moving branches can affect performance. A photocell responds to surrounding light levels, so it can control dusk-to-dawn operation without detecting movement. In security lighting, a timer may work with the sensor to limit how long the light remains on.
From the GMB Electric team
When we install or check a Motion Sensor, we verify the wiring, mounting position, coverage area, and control settings. We also test the connected security lighting from likely approach paths and check for conditions that could cause unwanted activation, such as heat sources, reflective surfaces, or moving vegetation.
Motion Sensor in Practice: A Real-World Example
A homeowner may place a security light with a Motion Sensor near a side entrance. The sensor detects movement along the approach path and signals the light to turn on, helping provide illumination when someone enters the coverage area.
Related Terms
Photocell
A photocell is a light-sensitive electrical control that switches outdoor lighting on when surrounding light fades…
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