Abstract:
A motion detector comprises a housing having a front side and a back side. Conductors are disposed on the back side so as to electrically connect to a wiring module installed within an electrical box. An infrared (IR) sensor is mounted within the housing and configured to receive IR radiation focused from a lens disposed on the front side. The IR sensor generates a sensor signal in response to motion across the field-of-view of the lens. A controller is responsive to the sensor signal so as to generate a switch signal. A relay is responsive to the switch signal so as to switch an electrical power source connecting to an electrical power load via the conductors and the wiring module.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application relates to prior U.S. Provisional Application No. 60/631,100 entitled  Modular Motion Detector , filed Nov. 26, 2004; U.S. Provisional Application No. 60/654,321 entitled  Modular Motion Detector , filed Feb. 19, 2005; and U.S. Provisional Application No. 60/715,456 entitled  Motion Detector Module , filed Sep. 10, 2005, all of the aforementioned prior applications incorporated by reference herein. 
    
    
     BACKGROUND OF THE INVENTION 
     Motion detectors are security system components that can trigger an alarm in the event of a burglary, fire or other critical conditions. Motion detectors are also energy conservation components, which can shut-off lights or disable other power consuming devices when there is no perceivable activity. Motion detectors utilize a variety of technologies, such as video cameras, ultrasonic emitter and detector combinations and infrared sensors in order determine if movement is occurring within a target area. 
     SUMMARY OF THE INVENTION 
     One drawback to conventional motion detectors is the necessity of custom installation. A motion detector typically requires physical and electrical connection to an existing or newly installed junction box. Although motion detectors are available that plug into conventional outlets, the choice of location and function is limited, and protrusion from the outlet is undesirable. 
     A modular motion detector is configured to be removably mounted to a wiring module. The wiring module can be either wired for a single throw or a three-way switch. As such, any of a switch function, a dimmer switch function or a motion detector function can be advantageously implemented without rewiring and without requiring professional installation. Wiring modules and functional modules that implement switch or dimmer switch functions are described in U.S. Pat. No. 6,884,111 entitled  Safety Module Electrical Distribution System , assigned to ProtectConnect, Irvine, Calif. and incorporated by reference herein. 
     One aspect of a motion detector is a housing having a front side and a back side. Conductors are disposed on the back side so as to electrically connect to a wiring module installed within an electrical box. An infrared (IR) sensor is mounted within the housing and configured to receive IR radiation focused from a lens disposed on the front side. The IR sensor generates a sensor signal in response to motion across the field-of-view of the lens. A controller is responsive to the sensor signal so as to generate a switch signal. A relay is responsive to the switch signal so as to switch an electrical power source connecting to an electrical power load via the conductors and the wiring module. 
     Another aspect of a motion detector is an electrical box configured to accept electrical conductors in communications with a power source and a power load. A wiring module having a wiring side and a functional side is mounted within the electrical box. A motion detector module having a front side and a back side is removably plugged into the wiring module. The wiring module wiring side terminates the electrical conductors, and the functional side has wiring module contacts electrically connected to the terminations. The motion detector module front side has a lens for receiving IR radiation, and the back side has motion detector module contacts that are removably and electrically connected to the wiring module contacts. The motion detector module is responsive is responsive to motion within the field-of-view of the lens so as to connect the power source with the power load via the motion detector module contacts. In one embodiment, the motion detector may further include a relay disposed within the motion detector module. The relay has a switch movable between a closed position connecting the power source to the power load and an open position disconnecting the power source from the power load. The switch moves between open and closed positions only upon the zero-crossing of the AC power source, i.e. when the power source voltage or current changes polarity. 
     A further aspect of a motion detector routes an electrical power source and an electrical power load to an electrical box. A wiring module is mounted within the electrical box, and the power source and load are terminated at the wiring module. A motion detector module is plugged into the wiring module so as to allow the motion detector module to communicate with the power source and load via the wiring module. The power source is switched to the load in response to motion in the field-of-view of the motion detector module. In one embodiment, a switch module for manually switching the power source to the load is unplugged from the wiring module and interchanged with the motion detector module. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1A-B  are front perspective views of a motion detector module unplugged from and plugged into a wiring module, respectively; 
         FIGS. 2A-C  are front, back and exploded perspective views, respectively, of a motion detector module; 
         FIGS. 3A-B  are front and back perspective views, respectively, of a front shell; 
         FIGS. 4A-B  are front and back perspective views, respectively, of a back shell; 
         FIGS. 5A-B  are front and back perspective views, respectively, of a cover assembly; 
         FIGS. 6A-C  are front, back and exploded perspective views, respectively, of a printed circuit board (PCB) assembly; 
         FIG. 7  is a functional block diagram of a motion detector module; and 
         FIG. 8  is a flow diagram for a main control unit (MCU) of the motion detector module. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIGS. 1A-B  illustrate a motion detector module  200  unplugged from and plugged into a wiring module  100 . The wiring module  100  installs within a conventional electrical box (not shown) using box mounts  110  that attach to an electrical box with fasteners  112 . The wiring module  100  physically mounts and electrically connects a variety of functional modules, including a motion detector module  200 , to a power source and a power load routed to an electrical box. The motion detector module  200  advantageously plugs into and out of the wiring module  100  without professional installation and without exposure or access to electrical system wiring. Attachment ears  310  attach the motion detector module  200  to module mounts  120  with corresponding fasteners  122 . 
     As shown in  FIGS. 1A-B , the motion detector module  200  functions with the wiring module  100  as an electrical power switch responsive to motion within the field-of-view of a sensor lens or to a manually operated actuator, both mounted on the front of the motion detector module  200 . The motion detector module  200  mounts generally flush with a wall surface, with only an aesthetically pleasing curved cover assembly  500  protruding from the wall. A motion detector module  200  may be configured to be wall-mounted or ceiling-mounted. Further, the motion detector module  200  can be adapted for electrical power distribution applications within buildings, automobiles or boats, to name just a few. 
       FIGS. 2A-C  illustrate a motion detector module  200  having a housing  205  with a cover assembly  500  on a front side  201 , shielded plugs  210  and a ground bar  620  on a back side  202  and attachment ears  310  on diagonally opposing corners. The cover assembly  500  has a sensor lens  510 , an indicator lens  520  and an actuator  530 . The shielded plugs  210  and the ground bar  620  are configured to physically and electrically connect the motion detector module  200  to a wiring module  100  ( FIGS. 1A-B ). In particular, the motion detector module  200  switches electrical power across the shielded plugs  210 , functioning, for example, as a SPST switch or as a three-way switch in response to motion within its field-of-view. The ground bar  620  provides a ground connection and functions as a key to orient the motion detector module  200  when plugging into the wiring module  100  ( FIGS. 1A-B ). The attachment ears  310  accept fasteners  122  that secure the motion detector module  200  to the wiring module  100  ( FIGS. 1A-B ). 
     As shown in  FIG. 2C , the housing  205  ( FIGS. 2A-B ) has a front shell  300  and a back shell  400  that enclose a printed circuit board (PCB) assembly  600 . The front shell  300  and the back shell  400  held together with fasteners  260 . The PCB assembly  600  provides the electronics to detect IR radiation, determine motion and switch electrical power, among other functions. The front and back shells  300 ,  400  are described in detail with respect to  FIGS. 3-4 , below. The cover assembly  500  is described in detail with respect to  FIGS. 5A-B  below. The PCB assembly  600  is described in detail with respect to  FIGS. 6A-B , below. The motion detector module functions are described with respect to  FIGS. 7-8 , below. 
       FIGS. 3A-B  illustrate a front shell  300  having an outside face  301 , an inside face  302 , attachment ears  310 , a lens cavity  320 , a sensor window  330 , adjustment apertures  340 , flexors  350 , a post aperture  360  and fastener holes  370 . The attachment ears  310  are located at diagonally opposite corners for mounting the motion detector module  200  ( FIGS. 1A-B ) to a wiring module  100  ( FIGS. 1A-B ), as described above. The lens cavity  320  physically supports and optically accommodates the sensor lens  510  ( FIGS. 5A-B ). The sensor window  330  is located proximate to and transfers light to a PIR sensor  710  ( FIG. 6A ). The adjustment apertures  340  accommodate adjustment screws  230  ( FIG. 2C ) that couple to trim pots  730  ( FIG. 6A ) through the front shell  300 , so that adjustments, described below, are accessible from the module front side  201  ( FIG. 2A ). The flexors  350  contact corresponding stops  532  ( FIG. 5B ) to provide tactile feedback to the actuator  530  ( FIG. 2C ). The post aperture  360  accommodates the switch post  534  ( FIG. 5B ), which physically actuates a mini-switch  630  ( FIG. 6A ) in response to a pressing of the actuator  530  ( FIG. 2C ). The fastener holes  370  accommodate the fasteners  260  ( FIG. 2C ) that attach the front shell  300  to the back shell  400  ( FIGS. 4A-B ). 
       FIGS. 4A-B  illustrate a back shell  400  having an inside face  402 , an outside face  401 , plug shields  410 , a ground bar aperture  420  and fastener holes  430 . The plug shields  410  provide a nonconductive shield portion of the shielded plugs  210  ( FIG. 2B ). Specifically, the plug shields  410  completely surround all sides of the power PCB prongs  610  ( FIG. 6B ). The ground bar aperture  420  allows a ground bar  620  ( FIG. 6B ) to protrude through the back shell  400 , providing a ground contact with the wiring module  100  (FIGS.  1 A-B). The fastener holes  430  allow fasteners  260  ( FIG. 2C ) to fixedly attach the back shell  400  to the front shell  300 . 
       FIGS. 5A-B  illustrate a cover assembly  500  having a sensor lens  510 , an LED lens  520  and an actuator  530 . The sensor lens  510  is adapted to receive and focus optical radiation for the PIR sensor  710  ( FIG. 6A ). The LED lens  620  indicates motion detection when illuminated by the LED  735  ( FIG. 6A ). The actuator  530  manually initiates the motion detector switching function, as described with respect to  FIG. 8 , below, and is removable to provide access to adjustment screws  230  ( FIG. 2C ). 
       FIGS. 6A-C  illustrate a printed circuit board (PCB) assembly  600  having a control PCB  601  and a power PCB  602 . The control PCB  601  has a pyroelectric infrared (PIR) sensor  710 , a manual control jumper  725 , adjustment pots  730 , an LED  735  and a mini-switch  740 , which are all functionally described with respect to  FIGS. 7-8 , below. The power PCB  602  has a DC power supply  750  and a relay  770 , also functionally described with respect to  FIGS. 7-8 , below. A control PCB connector  630  mates with a power PCB connector  640  to mechanically and electrically connect the PCB&#39;s  601 ,  602  in a piggyback configuration, as described in further detail with respect to  FIG. 7 , below. The power PCB also has power prongs  610  and a ground bar  620 , also described in further detail with respect to  FIG. 7 , below. 
       FIG. 7  illustrates a functional block diagram  700  for a motion detector module  200  ( FIGS. 1A-B ), which is divided between a control PCB  601  and a power PCB  602 , both described with respect to  FIGS. 6A-C , above. The control PCB  601  includes a PIR sensor  710 , a two-stage amplifier  715 , a main control unit (MCU)  720 , a manual control jumper  725 , lux, delay and sensitivity adjustments  730 , an LED  735  and a mini-switch  740 . The power PCB  602  includes a DC power supply  750 , an AC tap  755 , a relay driver  760  and a relay  770 . 
     As shown in  FIG. 7 , on the control PCB  601 , the PIR sensor  710  is responsive to optical radiation at IR wavelengths so as to detect motion, as is well-known in the art. The two-stage amplifier  715  is responsive to the PIR sensor  710  output so as to provide a motion detected output to the MCU  720 . A sensitivity adjustment pot  730  sets the gain for the final stage of the two-stage amplifier  715  so as to determine motion sensitivity. The MCU  720  processes the PIR sensor  710  output along with inputs from the mini switch  740 , the manual control jumper  725  and settings from the lux and delay adjustment pots  730  to actuate the relay  770 , as described with respect to  FIG. 8 , below. The MCU  720  also flashes the LED  735  to indicate motion detection, also described below. In one embodiment, the MCU is an EM78P458 8-bit microcontroller from Elan Microelectronics Corp., Taipei, Taiwan. 
     Also shown in  FIG. 7 , on the power PCB  602 , the DC power supply  750  converts the AC power inputs  610 ,  620  to DC voltage for the electronics on both PCBs  601 ,  602 . An AC tap  755  provides a low-current sample of the AC power waveform to the MCU  720 , advantageously allowing the MCU  720  to actuate the relay  770  at zero-crossings of the AC power waveform, i.e. when the AC voltage or current change polarity, so as to minimize relay arcing. The relay driver  760  is responsive to a MCU  720  switch signal so as to provide sufficient drive current to actuate the relay  770 . The relay  770  selectively connects and disconnects the power prongs  610  so as to switch power on and off to a load. In particular, the relay  770  has a switch movable between a closed position connecting power to the load and an open position disconnecting power from the load. 
       FIG. 8  illustrates the functional flow  800  of the MCU  720  ( FIG. 7 ), which determines at least a portion of the operational characteristics of the motion detector module  200  ( FIGS. 1A-B ). When power is first applied to the motion detector module  200  ( FIGS. 1A-B ), the MCU performs a power-on initialization sequence  805 . In a status step  810 , the MCU determines whether the manual control jumper  725  ( FIG. 7 ) is present and whether the mini switch  740  has been pushed. In an operating mode step  820 , if the manual control jumper is present, the motion detector module will be in auto mode  830 - 890 , otherwise it will be in manual mode. In manual mode, if the mini switch has been pushed and the previous mode was off, then the new mode is on and the relay is actuated to apply power to the load  821 . Likewise, if the previous mode was on, then the new mode is off and the relay is actuated to remove power to the load  823 . Otherwise, no action is taken and the status step  810  is repeated. 
     As shown in  FIG. 8 , in auto mode, motion detection is determined  830 . If motion is not detected, load on/off is checked  842 . If the load is not on, the status step  810  is simply repeated. Otherwise, the delay time from the last motion detection is determined  844 . If the delay time as set by the delay adjustment  730  ( FIG. 7 ) has not been exceeded, then the MCU simply returns to the status step  810 . If the delay time has been exceeded, then the load is turned off  846  and the status step  810  is repeated. 
     Also shown in  FIG. 8 , if motion is detected  830 , the LED  735  ( FIG. 7 ) is flashed  850 . In one embodiment, the LED is turned on for 10 ms. If the load is on  860 , the load on timer is reset  890  and the status step  810  is repeated. If the load is off  860 , the ambient light brightness is checked  870  relative to the lux adjustment  730  ( FIG. 7 ). If the ambient light is sufficient bright, the status step  810  is simply repeated. Otherwise, the load is turned on  880 , the load on timer is reset  890 , and the status step  810  is repeated. The ambient light brightness check assumes the load is, for example, an artificial light source. In other applications, the load could be, for example, an alarm or other security alert, and the lux adjustment could be set so that ambient light brightness would be irrelevant. 
     A motion detector module has been disclosed in detail in connection with various embodiments. These embodiments are disclosed by way of examples only and are not to limit the scope of the claims that follow. One of ordinary skill in art will appreciate many variations and modifications.