Is performance affected by room size and location?

[DonpK]

I've mounted the RCWL-0516 on a small, solderless breadboard with a battery so it can be easily placed in different locations. It seems that the sensor's performance, that is, the trigger sensitivity, varies noticeably depending on the size of the room and where the unit is placed in the room.

Is this behavior to be expected? Since the unit works by interpreting reflected waves, it would make sense that where it is placed could affect its performance. Nearby objects might affect the quality of the reflected waves and whether the RCWL-0516 interprets them as movement.

[jocic]

I've been using a presence detector designed around RCWL-0516 for a few months now, and its performance is somewhat unstable. It seems that the sensitivity is temperature and voltage-dependent - on good days it's capable of detecting a cat through a wooden door or someone's presence within 7-9 meter radius, and on bad ones it struggles until it's within hands reach.

The highest sensitivity seems to be achieved by placing the module on the ceiling, or on the wall - somewhere around eye level while standing.