Useful motion and presence detectors

A motion detector can switch on the lights as you enter, while a programmed scene can provide softer lighting in the evening. The result depends on the configuration: the sensor alone does not choose music or a mood. Decide what should happen on arrival, while someone remains in the room and after they leave.

Where is motion detection useful?

Motion detectors are useful in corridors, walk-in wardrobes and on stairs. A model with a brightness sensor can make switching depend on the available daylight. Choose its position and mounting height from the product documentation. In a bathroom or at a desk, also consider someone sitting with very little movement.

What does a presence detector detect?

A PIR presence detector detects small movements; it does not directly detect a completely motionless person. Its range is not necessarily wider than that of a motion detector. Manufacturers may specify separate detection areas for walking and seated activity. Place the workstation within the appropriate area and keep the detector’s view unobstructed.

Brightness control and light switching

Constant-light control requires a brightness measurement, a controller and suitable dimmable luminaires or actuators. A simple switching threshold does not maintain a constant light level. Relate the ceiling measurement to conditions at the desk, and test the system in daylight, in the evening and after a manual override.

How should you test the settings?

Commissioning check: enter the room, sit down and work at a computer, then leave. Record when the lights should switch on and off and how automatic operation resumes after a button press. Comfort depends on selection and configuration, not simply on a product being called a presence detector.

Sources and further reading

Theben — motion and presence detection

Content updated: 8 September 2026.