What is a presence sensor?
A mmWave or radar sensor that detects stationary occupancy, not just motion.
The essentials
- Detects stationary occupancy, not only motion
- Uses mmWave radar, PIR, or ultrasonic fusion
- Drives lighting hold-on and AC setback
- Zoned detection per seat, desk, or sofa
Direct answer
A presence sensor detects whether a room is actually occupied — including people sitting still — using millimetre-wave radar, PIR fusion, or ultrasonic sensing. Unlike a plain motion sensor, it does not switch off the light when you stop moving. In UAE villas Smart Citizens uses presence sensors for lighting, AC setback, and occupancy-based scenes in offices, living rooms, and cinema rooms.
Detailed explanation
A presence sensor emits a low-power radio pulse and measures reflections. Micro-movements — breathing, small posture shifts — return enough signal to confirm a person is there. Better sensors expose zones so a desk area can trigger different logic than a sofa area.
In UAE offices and villas, presence sensors avoid the classic complaint of lights and AC turning off during a movie, meeting, or reading session — the sensor keeps state as long as the room is occupied.
Decision guide
Choose presence (mmWave)
living rooms, offices, cinemas
Choose motion (PIR)
corridors, walk-ins, staircases
Combine both
high-reliability whole-home occupancy
Common mistakes and best practices
What to avoid, what to do
- Mount on ceiling for 360° coverage
- Configure per-zone timeouts (short in halls, long in living)
- Combine PIR + mmWave in cinema rooms for reliability
- Placing a mmWave sensor behind glass or metal
- Overlapping sensors without zoning, causing hunting
- Tuning sensitivity too high, tracking pets or curtains
Frequently asked questions
Frequently asked questions
Is a presence sensor better than motion?
For stationary rooms yes; for corridors PIR is still adequate and cheaper.
Does mmWave detect pets?
Correctly tuned models filter small pets; unfiltered they may trigger.
Does it need line of sight?
It penetrates thin materials but not thick walls, glass, or metal.
Design your smart environment with Smart Citizens
Talk to Smart Citizens engineers for a bespoke design, budget estimate, and rollout roadmap.