Bubble movement detector security system

Claim 2

Security protection apparatus for warning of presence of a person or for warning of movement of a body, said protection apparatus including: movement sensing apparatus for sensing the presence of the person or the movement of the body and signalling means operative in response to operation of the movement sensing apparatus to generate a warning signal, said movement sensing apparatus including a liquid charged chamber mounted to said body, which is normally stationary, said chamber having a bubble movable within the chamber so that surfaces of the bubble within the chamber move as orientation of the chamber is changed or as the chamber is vibrated, electromagnetic radiation means arranged to emit electromagnetic radiation into the chamber along paths which are located generally along the line of movement of the bubble to impinge on two respective end edges of the bubble and be reflected laterally from those two end edges, radiation detecting means arranged to detect substantially independent of axial rotation of said chamber, radiation reflected laterally from the two end edges when the chamber is in a predetermined orientation in which the bubble adopts a predetermined position within the chamber, and to generate two intensity signals each being indicative of the intensity of the radiation reflected from a respective one of said two end edges and received by said radiation detecting means when the bubble is in said predetermined position and throughout a continuous range of possible positions of the said two end edges of the bubble substantially independent of axial rotation of said chamber, signal comparing means for continuously receiving the two intensity signals so as to determine whether the two end edges have moved from or are vibrating about the positions of said two end edges when said chamber is in said predetermined orientation so as to thereby determine whether the chamber has been moved from said predetermined orientation or is being vibrated, said signal comparing means being operative to generate a movement signal indicative of movement of or vibration of said two end edges as a result of movement of vibration of said chamber, said signalling means being responsive to said movement signal to generate a warning signal, said chamber being provided within a housing and said radiation detecting means being positioned to detect radiation reflected by the end edges of the bubble through respective recesses in the housing, which recesses are immediately opposite the bubble end edges when the chamber is in said predetermined orientation.

Claim 3

Security protection apparatus as claimed in claim 1, wherein the internal surface of said liquid chamber is barrel shaped.

Claim 4

Security protection apparatus as claimed in claim 1, wherein said housing is proportioned to form an autonomous alarm system which may be applied to small articles.

Claim 5

Security protection apparatus as claimed in claim 1, wherein said radiation emitting means are arranged to emit substantially equal intensity radiation beams into the chamber to impinge on said two end edges of the bubble which are symmetrically located relative to the bubble configuration, the radiation detecting means being symmetrically located relative to the bubble position when the chamber is in said predetermined orientation so as to detect radiation reflected symmetrically from said end edges, said signal comparing means being operable to continuously compare the two intensity signals so as to detect when the two intensity signals are equal to each other or when there is imbalance between the two intensity signals as a result of movement of the bubble from or about said predetermined position.

Claim 6

Security protection apparatus as claimed in claim 1, wherein opposed ends of said housing are provided with respective radiation-source-accommodating recesses having therein respective radiation emitting means arranged to emit radiation longitudinally into the liquid charged chamber, the two radiation emitting means being substantially identical and the radiation emitted thereby being attenuated equally in passing into and along said chamber before encountering and being reflected by the end edges of the bubble.

Claim 7

Security protection apparatus as claimed in claim 1, wherein said housing comprises a molded transparent plastic block, said block providing mountings for light emitting diodes constituting said radiation emitting means, photodetectors constituting said radiation detecting means, and a hybrid integrated circuit substrate having said signal comparing means provided thereby, said substrate providing for selective assembly therewith of discrete miniature differential amplifiers operative to compare the two intensity signals thereby providing for interchangeability of amplifiers for particular purposes of the apparatus.

Claim 8

Security protection apparatus as claimed in claim 1, wherein said signal comparing means includes a differential amplifier for comparing the two intensity signals, the output of the differential amplifier being applied to a relay, said relay being operable independent of the voltage polarity of the differential amplifier output whereby an imbalance between said two intensity signals in either direction can cause operation of said relay, said signalling means including a radio transmitter operable in response to operation of said relay to generate a radio signal indicative of movement or of vibration of said two end edges.

Claim 9

Security protection apparatus as claimed in claim 1, wherein said signalling means includes a radio signal transmitter operable to generate a radio signal in response to said movement signal, said radio signal transmitter including an oscillator for generating a carrier frequency signal, said carrier frequency signal being connected to a prescaler the output of which is applied to a binary counter so as to make available a plurality of differing frequency signals for modulation of the carrier frequency signal.

Claim 10

Security protection apparatus as claimed in claim 8, wherein said signalling means includes a selectively operable switching means for selecting one or more of said differing frequency signals to be used for modulation of said carrier frequency signal.

Claim 11

Security protection apparatus as claimed in claim 1, wherein said signalling means includes a radio signal transmitter for generating and transmitting a radio frequency signal in response to said movement signal, said radio transmitter including an oscillator for generating a carrier frequency signal, said carrier frequency signal being modulated by one or more frequencies derived from said oscillator-generated carrier frequency signal to enable generation of a self modulated radio signal.

Claim 12

Security protection apparatus as claimed in claim 10, wherein said radio transmitter includes a dividing means for dividing the carrier frequency signal, the output of the dividing means being applied to a modulating diode connected to the midpoint of a radio frequency choke network driven by the carrier frequency signal.

Claim 13

Security protection apparatus for warning of presence of a person or for warning of movement of a body, said security protection apparatus including: movement sensing apparatus for sensing the presence of the person or the movement of the body and signalling means operative in response to operation of the movement sensing apparatus to generate a warning signal, said movement sensing apparatus including a chamber mounted to said body, which is normally stationary, said chamber being charged with a liquid and having a bubble movable within the chamber so that surfaces of the bubble within the chamber move as the orientation of the chamber is changed or as the chamber is vibrated, said liquid having a low viscosity so that relatively small changes in the orientation of the chamber cause corresponding changes in the position of the bubble within the chamber and such that ambient temperature variations cause expansion and contraction of bubble size, radiation emitting means arranged to emit radiation into the chamber along paths which are located generally along the line of movement of the bubble to impinge on two respective convex surface parts of the bubble and be reflected laterally from those surface parts in a plurality of directions relative to the said paths, two radiation detecting means, each being arranged to detect substantially independent of axial rotation of said chamber, radiation reflected laterally from said respective surface parts when the chamber is in a predetermined orientation in which the bubble adopts a predetermined position with the chamber as well as when the chamber is not in said predetermined orientation and each detecting means being operative to generate an intensity signal indicative of total reflected radiation intensity detected thereby from said respective surface parts when the bubble is in said predetermined position and throughout a continuous range of possible positions of said surface parts of the bubble, substantially independent of axial rotation of said chamber, said intensity signals generated by said detecting means being equal to each other but not equal to a constant value when said bubble is in said predetermined position throughout a range of ambient temperatures and consequent range of bubble sizes, signal comparing means for continuously receiving the two intensity signals and for continuously comparing those two signals so as to determine whether the said two surface parts have moved from or are vibrating about the positions of said two surface parts when said chamber is in said predetermined orientation as indicated by an inequality in said intensity signals which is substantially temperature independent so as to thereby determine whether the chamber has been moved from said predetermined orientation or is being vibrated, said signal comparing means being operative to generate a movement signal indicative of movement of or vibration of said surface parts as a result of movement or vibration of said chamber by a person or movement of the body, said signalling means being responsive to said movement signal to generate a warning signal, said chamber, radiation emitting means, radiation detecting means, and signal comparing means together with a power supply for said apparatus all being mounted in a housing, the housing being mounted to a buoyant body for floating in a swimming pool whereby surface waves generated in the swimming pool when a person or other object enters the pool cause a change in orientation of the chamber sufficient for generation of said movement signal, said buoyant body including a plurality of generally coplanar radiating arms having buoyant pieces mounted thereto, the length of at least one of the arms being selectively adjustable so as to enable selective adjustment of the sensitivity of the buoyant body to movement in response to surface waves in the swimming pool.

Claim 14

Security protection apparatus for warning of presence of a person or for warning of movement of a body, said security protection apparatus including: movement sensing apparatus for sensing the presence of the person or the movement of the body and signalling means operative in response to operation of the movement sensing apparatus to generate a warning signal, said movement sensing apparatus including a chamber mounted to said body, which is normally stationary, said chamber being charged with a liquid and having a bubble movable within the chamber so that surfaces of the bubble within the chamber move as the orientation of the chamber is changed or as the chamber is vibrated, said liquid having a low viscosity so that relatively small changes in the orientation of the chamber cause corresponding changes in the position of the bubble within the chamber and such that ambient temperature variations cause expansion and contraction of bubble size, radiation emitting means arranged to emit radiation into the chamber along paths which are located generally along the line of movement of the bubble to impinge on two respective convex surface parts of the bubble and be reflected laterally from those surface parts in a plurality of directions relative to the said paths, two radiation detecting means, each being arranged to detect substantially independent of axial rotation of said chamber, radiation reflected laterally from said respective surface parts when the chamber is in a predetermined orientation in which the bubble adopts a predetermined position with the chamber as well as when the chamber is not in said predetermined orientation and each detecting means being operative to generate an intensity signal indicative of total reflected radiation intensity detected thereby from said respective surface parts when the bubble is in said predetermined position and throughout a continuous range of possible positions of said surface parts of the bubble, substantially independent of axial rotation of said chamber, said intensity signals generated by said detecting means being equal to each other but not equal to a constant value when said bubble is in said predetermined position throughout a range of ambient temperatures and consequent range of bubble sizes, signal comparing means for continuously receiving the two intensity signals and for continuously comparing those two signals so as to determine whether the said two surface parts have moved from or are vibrating about the positions of said two surface parts when said chamber is in said predetermined orientation as indicated by an inequality in said intensity signals which is substantially temperature independent so as to thereby determine whether the chamber has been moved from said predetermined orientation or is being vibrated, said signal comparing means being operative to generate a movement signal indicative of movement of or vibration of said surface parts as a result of movement or vibration of said chamber by a person or movement of the body, said signalling means being responsive to said movement signal to generate a warning signal, said chamber, radiation emitting means, radiation detecting means, and signal comparing means together with a power supply for said apparatus all being mounted in a housing, the housing being mounted to a buoyant body for floating in a swimming pool whereby surface waves generated in the swimming pool when a person or other object enters the pool cause a change in orientation of the chamber sufficient for generation of said movement signal, said buoyant body including a plurality of generally coplanar radiating arms having buoyant pieces mounted thereto, the length of at least one of the arms being selectively adjustable so as to enable selective adjustment of the sensitivity of the buoyant body to movement in response to surface waves in the swimming pool.

Claim 15

Security protection apparatus for warning of presence of a person or for warning of movement of a body, said security protection apparatus including: movement sensing apparatus for sensing the presence of the person or the movement of the body and signalling means operative in response to the operation of the movement sensing apparatus to generate a warning signal, said movement sensing apparatus including a liquid charged chamber mounted to said body, which is normally stationary, said chamber having a bubble movable within the chamber so that the surfaces of the bubble within the chamber move as orientation of the chamber is changed or as the chamber is vibrated, radiation emitting means arranged to emit radiation into the chamber along two paths to impinge on two respective surface parts of the bubble and be reflected laterally from those two surface parts, radiation detecting means arranged to detect radiation reflected laterally from the two surface parts when the chamber is in a predetermined orientation in which the bubble adopts a predetermined position with the chamber and to generate two intensity signals indicative of intensity of radiation reflected from said two surface parts and received by said radiation detecting means when the bubble is in said predetermined position and throughout a continuous range of possible positions of the said two surface parts of the bubble, signal comparing means for receiving the two intensity signals and for continuously comparing those two signals so as to determine whether the two surface parts have moved from or are vibrating about the positions of said two surfaces parts when said chamber is in said predetermined orientation to thereby determine whether the chamber has been moved from said predetermined orientation, said signal comparing means being operative to generate a movement signal indicative of movement of said two surface parts as a result of movement of said chamber by a person or movement of the body, said signal comparing means being of variable sensitivity so that, when operated in a less sensitive mode of operation, said movement signal is not generated except by relatively large amplitude movement of the chamber from said predetermined orientation, and when operated in a more sensitive mode of operation, said movement signal is generated in response to either relatively large amplitude movement of the chamber or small amplitude vibrational movement of the two surface parts of the bubble, said signalling means being responsive to said movement signal to generate a warning signal.

Claim 16

Security protection apparatus for warning of presence of a person or for warning of movement of a body, said security protection apparatus including: movement sensing apparatus for sensing the presence of the person or the movement of the body and signalling means operative in response to the operation of the movement sensing apparatus to generate a warning signal, said movement sensing apparatus including a liquid charged chamber mounted to said body, which is normally stationary, said chamber having a bubble movable within the chamber so that the surfaces of the bubble within the chamber move as orientation of the chamber is changed or as the chamber is vibrated, radiation emitting means arranged to emit radiation into the chamber along two paths to impinge on two respective surface parts of the bubble and be reflected laterally from those two surface parts, radiation detecting means arranged to detect radiation reflected laterally from the two surface parts when the chamber is in a predetermined orientation in which the bubble adopts a predetermined position with the chamber and to generate two intensity signals indicative of intensity of radiation reflected from said two surface parts and received by said radiation detecting means when the bubble is in said predetermined position and throughout a continuous range of possible positions of the said two surface parts of the bubble, signal comparing means for receiving the two intensity signals and for continuously comparing those two signals so as to determine whether the two surface parts have moved from or are vibrating about the positions of said two surfaces parts when said chamber is in said predetermined orientation to thereby determine whether the chamber has been moved from said predetermined orientation, said signal comparing means being operative to generate a movement signal indicative of movement of said two surface parts as a result of movement of said chamber by a person or movement of the body, said signal comparing means being of variable sensitivity so that, when operated in a less sensitive mode of operation, said movement signal is not generated except by relatively large amplitude movement of the chamber from said predetermined orientation, and when operated in a more sensitive mode of operation, said movement signal is generated in response to either relatively large amplitude movement of the chamber or small amplitude vibrational movement of the two surface parts of the bubble, said signalling means being responsive to said movement signal to generate a warning signal.

Claim 17

Security protection apparatus as claimed in claim 13, wherein said signal comparing means is operable in its said less sensitive mode of operation when ambient light intensity is relatively high and is operable in its said more sensitive mode of operation when the ambient light intensity is relatively low, whereby said security protection apparatus is more sensitive under dark ambient conditions.

Claim 18

Security protection apparatus as claimed in claim 14, wherein said signal comparing means includes light sensitive means operative to change the sensitivity of the signal comparing means from its less sensitive mode of operation to its more sensitive mode of operation upon detection of a reduction in ambient light intensity.