Can a PIR Ceiling Motion Sensor be Wall-Mounted?

Yes, a PIR ceiling motion sensor can be wall-mounted. While these devices are really intended for use on the ceiling, they will still work when mounted on the wall. This is true whether you are using a wireless ceiling-mount motion sensor or a hardwired ceiling-mount motion sensor.

Ceiling-mount motion sensors are also known as 360-degree motion sensors. These sensors are designed to be mounted on the ceiling and look downward. For a ceiling-mount motion sensor, the coverage area is usually described in terms of diameter. The higher up you have the ceiling-mount motion sensor, the larger the diameter for the coverage area will be. However, you want to avoid mounting these motion sensors too high, as doing so will leave them unable to detect the movement below.

If you mount a ceiling-mount motion sensor on the wall, then the sensor will look outward instead of downward. The detection zone will be a sort-of "cone shape" area protruding out from the sensor. If you move past the sensor, the device will still detect the change in infrared (IR) energy and activate like normal. Really, a ceiling-mount PIR motion sensor is no different than a regular PIR motion sensor. The only major difference is that they have different detection zones. A ceiling-mount motion sensor will "look" in a cone-shape out from the sensor, while a standard motion sensor will span out across the room.

Mounting a ceiling-mount motion sensor on a wall can be useful in a few unique situations. By doing this, the motion sensor will respond when someone walks directly past the sensor, while ignoring the most of the motion that occurs throughout the rest of the room. This can be good if you only want your system to respond for motion in that direct spot, while generally ignoring movement for the rest of the area.

One useful application for this is if you mount the ceiling-mount motion sensor on a wall right by a doorway. In that case, the motion sensor would respond to someone entering or exiting the room, but not to someone moving around the room on the other side. Of course, you could get the same result by mounting the motion sensor directly above the doorway on the ceiling, as is intended. But if you were to mount it on the wall, then it would still work just fine.