Doppler-radar movement detector, e.g. for automatic door - is protected by cover over circuit board and substrate protruding from moulded cavity on frame around monitored space

摘要

The radar signal processing unit is arranged on a circuit board (2) fixed to the back of the substrate (1) in a U-shaped holder (3). A pin projecting beyond each edge of the board slides in an arcuate slot in an end plate (e.g. 30) of the holder as the substrate is tilted through about 45 deg. in a cavity (40) of a moulding (4) on the door frame. The cavity extends into a convex cover (5a) of circular cylindrical or elliptical cross-section. A rectangular slot antenna cut in the top of the substrate is directed at the space under surveillance. ADVANTAGE - Appts. is safeguarded against malicious damage or destruction to which door frame or wall-mounted devices are prone.