Housing containing a PIR sensor and a camera

Abstract: A combined PIR sensor and security camera comprising a housing (13) containing an integrally moulded PIR sensor lens (20) and a sealed camera lens (21) of fixed focal length. A lower part (15) of the housing is rotatable with respect to an upper part (14) thus to determine an angle of view of the PIR sensor and camera. The upper part (14) of the housing may be located behind a backplate (11) of an exterior lamp (10) with the lower part (15) protruding through an aperture therein. The PIR sensor and camera are connected to the lamp and a television monitor respectively whereby the presence of an adjacent person is detected both by the PIR sensor and the camera lens to energise the lamp and to transmit an image to the television monitor. The provision of a fixed focal length lens (21) sealed in the wall of the housing prevents the ingress of water, moisture or dirt when compared to a conventionally mounted camera having a variable focal length and thus moving parts.

Description: THIS INVENTION concerns a housing adapted to contain a PIR sensor and at least the lens of a security camera. The device is particularly, though not exclusively, intended to be mounted on a support being part of an exterior lighting assembly such that the PIR sensor operates to energise the light when a person approaches, and a security camera provides a transmitted image of the person. It is known to combine a PIR sensor and camera lens in a single housing adapted to be mounted on the exterior of a building but the lens conventionally is of variable focal length and thus requires moving parts to the effect that the lens cannot be sealingly mounted on the housing. This leads to the ingress of moisture which may damage the circuit components of the assembly. According to the present invention, there is provided, a combined PIR sensor and camera comprising a housing fronted by a PIR lens and camera lens; characterised in that the camera lens is sealingly retained in the housing wall and is adapted to produce an image at a fixed focal length. Preferably, the PIR lens and camera lens are separately disposed in the housing and sealingly engaged therewith. The housing is preferably rotatable thus to select the angle of view, individually or collectively, of the PIR lens and camera lens. An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:- Fig. 1 illustrates, in perspective, a combined PIR sensor and camera housed within an exterior lamp assembly; Fig. 2 is an enlarged perspective view of a PIR sensor and camera housing before installation of the lamp assembly; Fig. 3 is a partial cross-sectional view of the assembly. and Fig. 4 is a circuit diagram. Referring now to the drawings, in a practical application, an exterior lamp 10 has a backplate 11 to enable the assembly to be screwed to a wall usually adjacent the entrance to a building. The backplate 11 has, in its lower region, an aperture 12 through which protrudes a part of a combined PIR sensor and camera housing 13. Referring now to Fig. 2, the housing 13 comprises an upper part 14 arranged to be located behind the backplate 11 with a lower frontal part 15 protruding through the opening in the backplate. The lower part 15 of the housing is rotatable about an upright axis with respect to the upper part 14. The entire PIR and camera assembly is made from plastic and is fronted by a PIR lens 20 and a fixed focus camera lens 21. The PIR lens 20 is integrally moulded with the housing 13. The single element, pin-hole type camera lens 21 is installed and sealed into the housing after moulding. Within the housing 13 there will be located the usual PIR sensor 22 and certain image production components of the security camera. Other parts of the camera may be housed elsewhere and connected to a monitor for viewing within the building. The angle of view, vertically, of the PIR lens is determined by its physical characteristics whereas the field of view horizontally may be determined by rotation of the lower part of the housing as is the field of view from the camera lens. By providing a simple camera lens of fixed focal length sealed within the wall of the housing, the ingress of water or moisture or dirt is prevented. The rotational interface between the upper and lower parts of the housing is sealed by an O-ring, again to prevent the ingress of contaminants. Referring now to Fig. 4 the principal electrical components include a power supply unit 30 to which is connected mains voltage at 31 and to which is connected the PIR sensor 22 and via a preamplifier 40, a camera 32. The lamp 10 is supplied with mains voltage by an internal switch 33 driven by an opto-isolator unit 34. The PIR 22 is connected via a daylight sensing photocell 35 and, a first adjustable timer 36 to the opto-isolator 34. The PIR 22 is also connected via a second adjustable timer 37, via an on/off switch 39, to a scart lead 38, which is also connected to the camera 32. The scart lead may be connected to a domestic television receiver 41. The device operates such that if the PIR sensor 22 detects the presence of an adjacent person or other movement, then, if the ambient light level is low such as at night, a signal is fed from the PIR 22 via timer 36 to the opto-isolator 34 which, through its separated LED and photocell, actuates switch 33 to energise the lamp 10. The timer may be set, for example, at forty seconds such that the lamp remains illuminated for that period. With the scart lead 38 connected to the television receiver and if the receiver is switched on and tuned, the signal from the PIR simultaneously transmitted via timer 37 switches the circuitry within the television receiver to display, for the period set by timer 37, an image derived from the camera 32. Typically, the timer 37 may be set for ten seconds. Therefore, the arrival of a person, perhaps at the front door where the device is installed, will cause the lamp to light, if at night, and the image of that person viewed by the camera lens 21, to appear on the television screen. If required, a one or two-way audio intercom may be provided with a microphone disposed in housing 15 such that a voice transmission to the television set may occur. The presence of the opto-isolator 34 wherein no electrical connection exists between the switch terminals 33 and the PIR 22, prevents the possibility of mains voltage being fed back into the PIR and/or camera circuitry. The image transmitted by the camera to the television receiver is provided even if the lamp 10 is not illuminated, for example, in the hours of daylight. If required, a signal transmitted to the scart lead 38 as a result of a signal from the PIR, can energise an audible warning device and/or the camera 32 may be connected to a secondary monitor receiving an image from the camera when the television receiver is not switched on. The switch 39 may be opened to disable the connection to the television receiver whereby, if preferred, interruption of television programmes is avoided.

Claims: A combined PIR sensor and camera comprising a housing fronted by a PIR lens and a camera lens; characterised in that the camera lens is sealingly retained in the housing wall and is adapted to produce an image at a fixed focal length. A combined PIR sensor and camera according to Claim 1, wherein the PIR lens and camera lens are separately disposed in the housing and sealingly engaged therewith. A combined PIR sensor and camera according to Claim 1 or Claim 2, wherein the housing includes at least a part thereof which is rotatable thus to select the angle of view, individually or collectively, of the PIR lens and camera lens, the rotatable and fixed parts of the housing including a sealed interface to prevent the ingress of contaminants. A combined PIR sensor and camera according to any preceding claim, wherein the PIR lens is integrally moulded with the housing. A combined PIR sensor and camera according to any preceding claim, wherein the camera lens is installed and sealed into the housing after production thereof. A combined PIR sensor and camera according to any preceding claim, wherein the housing contains a PIR sensor and at least one image production component of the camera. A combined PIR sensor and camera according to any preceding claim, wherein the housing includes a part adapted to be located behind a backplate of a lamp with a lower frontal part of the housing protruding forwardly through an opening in the backplate. A combined PIR sensor and camera according to any preceding claim, including a first adjustable timer connecting the sensor to the camera whereby a signal from the camera may for a selected time be transmitted to a television monitor, and including a second adjustable timer whereby the PIR sensor may, for a predetermined time, be connected to an opto-isolator and switch for energising a lamp. A combined PIR sensor and camera according to any preceding claim, including a daylight sensing photocell whereby a signal from the PIR sensor to energise a lamp may be interrupted during hours of daylight. A combined PIR sensor and camera according to Claim 8, including a switch operable to prevent an image from the camera being transmitted to the television monitor irrespective of a signal from the PIR sensor. A combined PIR sensor and camera according to Claim 8, including an audio intercom provided with a microphone disposed in the housing such that a voice transmission to the television monitor may occur.

Inventors: GOUGH KEITH, GOUGH, KEITH
Applicants: BRIDISCO LTD, BRIDISCO LIMITED
Application year: 1999
Main classification: G08B13
IPC codes: G08B13, G08B15