The most common automation complaint — "the lights keep turning off while I'm still
in the room" — is almost never a bad sensor. It is the wrong type of sensor for the
room.
Two different questions
- Motion (PIR) answers: did something just move? Cheap, instant, and blind to
anyone sitting still. Reading a book, working at a desk, watching a film — PIR sees
an empty room. - Presence (occupancy) answers: is someone here, moving or not? Done with mmWave
radar, dual-technology sensing or camera-based analysis. Costs more, reacts a beat
slower, and actually solves the "lights off during dinner" problem.
Match the sensor to the room
| Room | Pick | Why |
|---|---|---|
| Hallway, stairs, closet | Motion | You are always moving there; speed matters more than stillness |
| Bathroom | Motion, short reset | Frequent movement; a long timeout feels broken |
| Home office | Presence | Hours of near-stillness defeat PIR |
| Living room | Presence | Film nights look vacant to PIR |
| Bedroom | Motion at the door only | Full-room presence at night causes midnight light shows |
Checks before you buy
- Timeout control. Whatever the type, you want to configure the "no activity"
window per room, not accept a fixed default. - Field of view vs. mounting height. A wide-angle sensor mounted where the
spec's diagram assumes it will be behaves differently. Check both. - Pets. PIR with pet immunity is common and imperfect; mmWave usually ignores
small animals better. Verify with the vendor's documented pet threshold. - Detection through obstacles. mmWave sees through glass and thin partitions —
occasionally detecting the hallway outside the room you placed it in. Plan
mounting accordingly. - Local automations. Confirm triggers run on the hub or device itself so lights
respond even when your internet is down.
Start here
Automate the hallway with a motion sensor first — it is forgiving and instantly
satisfying. Add presence sensing to the one room where you sit still the most, and
you will feel the difference the first evening.
Editorial note. This guide is compiled from official product documentation and practical buying checklists, not hands-on testing. Verify specifications and current pricing with the manufacturer before you buy. See our affiliate disclosure for how we fund this work.
