Aqara Motion Sensor P1

A conventional PIR motion sensor with an unusually long battery life, and the correct choice for spaces people pass through rather than sit in. Corridors, stairwells, store rooms, laundry areas and guest bathrooms are where it belongs. Understand what a PIR does before fitting one: it detects a change in infrared across its field of view, which means it sees movement, not people. Sit still on a majlis sofa for four minutes and the lights go out, because from the sensor's point of view the room emptied. For any room where people sit, buy the FP1E or the FP2 instead. Within its proper use the P1 is excellent. Two coin cells give a claimed five years, the detection interval is adjustable from one second upwards so a corridor light can react instantly rather than on a stock thirty second delay, and it covers roughly seven metres across a 170 degree arc. It is Zigbee, so an Aqara hub is required. Mounting is a magnetic ball base on adhesive, which lets you angle it down a corridor properly instead of accepting whatever the ceiling gives you.

• Up to five years on a set of batteries
• Reacts in one second instead of a fixed long delay
• Angles properly down a corridor on its magnetic base
• The right sensor for spaces people walk through, not sit in