Movement detector for room security - has harmonic filter whose inductors, capacitors and connecting leads are formed by double sided printed circuit board

摘要

The detector system for room security is designed to respond to any movement within the operating range. The unit is designed to be of small size coupled with an insensitivity to disturbances. An harmonic filter is connected between an oscillator and an antenna. The filter is a board on side of which carries strips of conductive material. The other side of the board has a layer of conductive material. The strips and layer of together form the inductors, capacitors and leads of the filter. The oscillator may also be constructed on this board.