Microwave motion sensor not functioning at stairwell

[Daryl Lim Ming Yen]

Hi guys,

I am working on a project to install staircase LED lights for a building. The new lights are fitted with microwave motion sensors. I have tested them at the lab and factory and the motion sensors are able to activate these lights smoothly.

When i install the lights at the stairwell, however, the motion sensors seem to be dead; they are not able to activate the lights even when we walk directly under them.

Are there any know issues with regard to these type of motion when they are installed at the confined areas such as stairwell? We have tried adjusting the gain of the sensor but to no avail.

Hope any microwave sensor experts out there can advise me. Thanks