Abstract:
An occupancy sensor and an automatic dimmer are connected in series with a light source. The detection of motion in the viewing area of the sensor starts the automatic dimmer which moves from its minimum brightness level to its maximum brightness level. One embodiment of the invention includes a key which can be operated to stop the automatic dimmer at some brightness level below the maximum brightness level which is reached if the key is not operated. A second embodiment provides a presetting device whereby the brightness level can be preset. When all motion in the viewing area ceases the automatic dimmer returns the brightness level to the minimum level at a slow rate.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention is directed to the field of controlling devices and more particularly to the control of electrical devices within prescribed and limited areas. 
     2. Description of the Prior Art 
     At present occupancy sensors are widely used to turn on electrical lamps when motion is detected within a prescribed area and to turn off the electrical lamps when no motion is detected within the prescribed area. The turn on and turn off are abrupt, often startling the person entering or leaving the area and the lights are turned on to their maximum brightness producing glare and discomfort. The brightness level can then be adjusted by use of a separate dimmer device. 
     SUMMARY OF THE INVENTION 
     An occupancy sensor is combined with an automatic dimmer and used to control the on/off state of a lamp and its level of brightness. When motion is detected in a prescribed area, the controlled light is turned on by the occupancy sensor to the minimum brightness level settable by said automatic dimmer. The automatic dimmer slowly increases to maximum brightness level at which it remains until no motion is detected within the prescribed area, at which time the automatic dimmer slowly decreases the level of brightness to the minimum level of brightness. In one embodiment, the automatic dimmer has a key which can be operated to stop the automatic dimmer at some level between the minimum and maximum levels of brightness. In another embodiment, the automatic dimmer has a presetting device to permit the level of brightness to be selected in advance of the operation of the automatic dimmer. It is an object of the present invention to provide a novel automatic switch/dimmer device. 
     It is another object of the present invention to provide a novel automatic switch/dimmer device which employs an occupancy sensor as an on/off switch. 
     It is another object of the present invention to provide a novel automatic switch/dimmer device which employs an occupancy sensor as an on/off switch and an automatic dimmer to control the level of brightness of an operated lamp. 
     It is still another object of the present invention to provide a novel automatic switch dimmer device wherein the automatic dimmer slowly operates between minimum and maximum brightness levels. 
     It is yet another object of the present invention to provide a novel automatic switch/dimmer device which can be stopped at a desired level of brightness during operation of the automatic dimmer. 
     It is another object of the present invention to provide a novel automatic switch/dimmer device which can be preset to a desired level of brightness. 
     Other objects and features of the invention will be pointed out in the following description and claims and illustrated in the accompanying drawings, which disclose, by way of examples, the principles of the invention, and the best modes which are presently contemplated for carrying them out. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the drawings in which similar elements are given similar reference characters: 
     FIG. 1 is a flow chart of a first embodiment of the invention. 
     FIG. 2 is a flow chart of a second embodiment of the invention. 
     FIG. 3 is a functional block diagram of a device constructed in accordance with the concepts of the invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Turning now to FIG. 3 the organization of the automatic switch/dimmer  10  constructed in accordance with the concepts of the invention is set forth. A pyroelectric detector and amplifier  12  provides a first signal to the microprocessor logic device  16 . The pyroelectric detector  12  may be an occupancy sensor or a motion sensor, commonly known as PIR (passive infra red) sensors which detect infrared emissions from moving personnel and respond to these emissions by providing an output signal on line  14  to micro processor logic device  16 . If no emissions are detected after a preselected duration, the motion sensor terminates its output signal. The motion sensor  12  may be one made by Leviton Manufacturing Co., Inc. Catalog No. 6771. The microprocessor logic device  16  may be a controller model 6320 also manufactured by Leviton Manufacturing Co., Inc. The output of microprocessor logic device  16  is fed to an output control  18  used to control the brightness level of operated lamps (not shown) and/or the speed of fans (not shown). The output control  18  may take the form of a dimmer module such as Leviton model 17700. When operated, the dimmer module  18  turns an operated lamp on or off. In response to signals received from microprocessor logic device  16 , the dimmer module  18  can also be stepped down from maximum light output to minimum brightness. Although the discussion thus far has been in terms of lighting, the automatic switch/dimmer device  10  can also be used to control a fan. The output of the microprocessor logic device  16  can be fed to a motor speed control to operate a fan (not shown) as is well known in the art. The fan also includes a delay network so that the fan will operate for a short period after the signals from the microprocessor logic device  16  terminate. 
     The microprocessor logic device  16  may be connected to a key  20  or a preset control  22 . The key  20  may be operated as the dimmer module  18  advances towards maximum brightness level to fix the brightness level at some value other than maximum brightness. The key  20  must be used each time the dimmer module  18  is turned on after having been turned off. The preset control  22  can be used to set the level of brightness and retains its setting after being turned off. It permits a repeatable setting each time a lamp is operated. The occupancy sensor  12 , microprocessor logic device  16  and dimmer module  18  are each powered from a power supply  24 . 
     Turning now to FIG. 1 there is shown a flow chart illustrating the operation of the automatic switch/dimmer device  10  of the instant invention employing a key. At the start of its operation, automatic switch/dimmer device  10  is in its attention state  30  in which it monitors a prescribed area for motion and the operated lamp and fan are off. The output of attention state block  30  is fed to is motion detection block  32 . If no motion is detected a signal is fed on line  34  back to block  30  to main the present condition of block  30 . If motion was detected a signal is fed on line  36  to block  38  which results in turning the operated lamps on and increasing the brightness level towards maximum brightness and turns the fan on. The state of the key is tested in block  40 . If the key is not operated then the lamp goes to maximum brightness as shown by block  42 . If the key has been activated a signal is fed via line  44  to block  46  where the lamp brightening stops at the key setting, the lamp remains on, and the device  10  returns to the attention state. The fan stays on and the lamp brightness can be readjusted. Motion is then tested in block  48  and if there is motion detected, indicating that personnel are in the prescribed area, a signal is fed back to block  46  via line  50 . This signal retains the lamp at the level selected. This operation will continue as long as motion is detected in the prescribed area. In the event no motion occurs, a signal will be fed along line  52  to block  54  which causes the operated lamp to slowly dim and starts the fan turnoff as set out in block  56 . While blocks  54  and  56  are operating they pass a signal on line  58  to a further motion detection block  60 . If no motion is detected, a signal is fed on line  62  to block  30  which places device  10  in its attention state. If block  60  shows that there is motion, then a signal on line  64  is fed to block  66  to cause the lamp to go on and to its previously selected brightness and block  66  is coupled to block  46  so that the sensor returns to its attention state and the fan stays on. The level of lamp brightness can now be readjusted. Also if motion is detected by block  48  a signal is fed via line  68  to line  50  and back to block  46 . 
     Thus, once motion is detected in a prescribed area which a sensor is monitoring, the lamps will be turned on at the lowest brightness level and will be increased to a maximum brightness level. The brightness level can go to a maximum value or can be stopped at some intermediate level by use of a key operated when the desired brightness level has been reached. The lamp brightening stops and the lamp remains on and the device  10  returns to its attention state, lamp brightness can be readjusted and the fan stays on. If motion is now detected by block  48 , a feedback loop via lines  68  and  50  retains the device  10  in its attention state motion is detected by block  48 , it is assumed that no personnel are present in the area and block  48  causes the device  10  goes to its attention state. The operated lamp is slowly dimmed to minimum brightness level block  45  and the fan is turned off by block  56 . Motion is still monitored by block  60  in the area to prevent turn off of the lamp and fan while someone is still in the area. If motion is detected, by block  60 , a signal on line  64  is applied to block  66  and the lamp goes on to previously selected brightness and a signal is fed via line  50  to block  46  to retain the lamp at the set level. If no motion is detected by the device  10  returns to its attention state. Once the device  10  is turned off the key selected brightness level is lost and it must be keyed in again each time the device  10  is put into service. 
     The flow chart of FIG. 2 shows a form of device  100  which can be preset to a desired level of brightness and will retain such setting when device  100  is turned off. Block  30  shows the device  100  in its attention state, monitoring for motion, with the lamp and fan off. Block  32  shows the testing for the presence of motion. If no motion is detected a signal via line  34  retains block  30  in its attention state. In the presence of motion a signal is fed via line  36  to block  102  which turns on the lamp and increases the lamp brightness from a minimum to the preselected or preset brightness and turns the fan on. A signal is fed from block  102  via line  104  to block  46 . The lamp remains on, the fan stays on and the device  100  returns to its attention state. The lamp brightness can be readjusted. The detector  48  is checked and if motion is detected a signal is fed via lines  106 , 50  and  104  to block  46  to retain the lamp in its on condition. If no motion is detected an output signal is fed from block  48  to the blocks  54  and  56  via line  52 . Block  54  starts to dim the lamp slowly and block  56  starts the fan shut off. The detector  60  is checked for motion during the dimming operation and if no motion is detected, a signal is fed from block  60  to block  30  along line  62  to place the device  100  in its attention state. In the event motion is detected a signal is applied from block  60  to block  66  via line  108  to restore the lamp to its previously selected brightness and a signal is fed via line  50  to the input to block  46  to retain the lamp on and place system  100  in its attention state. 
     As was true of the device of FIG. 1, once motion is detected in a prescribed area which a sensor is monitoring, a lamp will be turned on by block  102  at the lowest brightness level and will be increased to a maximum brightness level. The brightness level can be increased to a maximum value or can be stopped at some intermediate level by use of the preset device  22 . The lamp brightness stops increasing when the preset value is reached and the lamp remains on. If no motion is detected a signal is provided via line  34  to retain the detector or sensor  30  in its attention state with the lamp and fan off. If motion is detected by block  32 , a signal is fed to block  102  via line  36  and then via line  104  to block  46 , the lamps and fan remain on and the device  100  returns to its attention state. At this time the brightness level of the lamp can be readjusted or reset. Sensor  48  is checked and if motion is detected a signal is fed back via lines  106  and  50  to block  46  to retain the lamp at its preset brightness level and the sensor in its attention state. In the absence of motion a signal is provided to block  54  via line  52  cause the lamp to slowly dim and the fan to initiate its shut down due to the signal on line  52  from block  48  to block  56 . The detector  60  is monitored during this dimming and shut down. If no motion is detected a signal on lines  62  to block  30  places the device  100  in its attention state with the lamp and fan off. The detection of motion causes the lamp to return to its previously selected level of brightness and causes the lamp to stay on, the fan to stay on and the detector or sensor block  30  to be in its attention state. 
     While there have been shown and described and pointed out the fundamental novel features of the invention as applied to the preferred embodiments, as are presently contemplated for carrying them out, it will be understood that various omissions and substitutions and changes of the form and details of the devices illustrated and in their operation may be made by those skilled in the art, without departing from the spirit of the invention.