Abstract: An intrusion detection assembly including an intrusion detector including an inner housing, a detector disposed within the inner housing and a lens for focusing light from outside the inner housing onto the detector, and an outer housing which is generally sealed from the outside and defines a window which is generally transparent to light which is detected by the detector, wherein the intrusion detector is spaced from the window so as to define a region of high sensitivity between the lens and the window which is sealed from the outside environment.

Abstract: Apparatus for determining the authenticity of banknotes including a housing configured for being held in a single hand; a magnetic ink sensing head movably mounted in the housing and providing an electrical output indicating the presence of magnetic material in the vicinity thereof during operation thereof in scanning a banknote; sensible output indication providing apparatus responsive to the electrical output of the sensing head; and ON-OFF switch apparatus operated by the relative positioning of the sensing head and the housing for operating the determining apparatus only when the magnetic ink sensing head is in a predetermined position relative to the housing characteristic of operation thereof. The housing may be configured to lie coplanar with the sensing head during operation thereof for determining the orientation thereof.