An LED light with a sensor switches on by itself when you approach and off again when you leave. Handy at the front door, in the garage, on the stairs or in the shed, and it saves electricity. But which motion sensor should you choose, and how do you set it up properly? In this guide you'll read about the difference between PIR, radar and a dusk switch, and what to look out for.
In short
- PIR sensor: responds to heat and movement. The standard choice for indoors and outdoors.
- Radar (microwave): also detects through glass or thin walls, but triggers false alarms more easily.
- Dusk switch: makes sure the light only comes on in the dark.
- Outdoors: choose at least IP44, and preferably IP65 in the open air.
Jump straight to:
PIR, radar or dusk switch?
PIR motion sensor
PIR stands for passive infrared. The sensor notices when a warm object (you, a car) moves through its field of view. This works best when you walk across the detection area rather than straight towards the sensor. For most homes, PIR is the best choice.
Radar or microwave sensor
A radar sensor sends out a signal and responds to changes. It also sees through glass, plastic and thin walls, and it is more sensitive. That means it doesn't need a clear line of sight as much, but it triggers false alarms more easily, for example from trees or cars outside the range.
Dusk switch
A dusk switch measures the daylight and switches the lamp on when it gets dark. It is usually combined into the motion sensor, so the lamp only burns when it is dark and someone is there.
Light with built-in sensor or separate detector
A floodlight or wall light with a built-in sensor is the easiest: hang it up and connect it. A separate detector is more flexible, because you can switch several lights with it. Take a look at our LED floodlights and LED lighting for the garden.
Setting up a motion sensor properly
Most motion sensors have three settings, often with small dials.
Range or sensitivity (SENS)
This determines how far the sensor looks. Don't set it higher than necessary, otherwise the light comes on for every cat or passer-by. Many PIR detectors reach about 8 to 12 metres.
Delay time (TIME)
This is how long the lamp stays on after the movement stops. Choose anything from a few seconds to a few minutes, depending on the location: short for a stair landing, longer for a garden path.
Dusk setting (LUX)
This determines how much daylight is allowed before the lamp comes on. At the moon (or the lowest setting) the lamp only works in the dark, at the sun it also responds during the day. Test the setting at dusk, because during the day you can't tell whether it is right.
Where do you put a motion sensor?
Height and direction
Mount a PIR detector at a height of about 2 to 2.5 metres and aim it so that people walk across its field of view. Don't point it at a busy road, a tree blowing in the wind or a heat source such as a chimney or an air conditioner.
Indoors: stairs, hallway, garage, basement
Indoors, a sensor is ideal in places where you come in with your hands full. Also read Garage lighting and Basement lighting.
Outdoors: front door, driveway, garden
Outdoors, everything has to withstand water. See IP ratings explained and Installing outdoor lighting. No power socket nearby? Then take a look at solar LED lighting.
Sensor and LED together
LED uses little power. Some older detectors need a minimum load, which makes an LED keep glowing or flicker. Choose a detector that is suitable for LED. You can read more about this in Troubleshooting LED lighting.
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Frequently asked questions
What is the difference between PIR and radar?
Why does my sensor light keep switching on by itself?
Does a motion sensor also work during the day?
Can I hang an LED light with a sensor outdoors?
Which delay time should I choose?
Kind regards,
Bas / LEDPLANET.NL