Patent Publication Number: US-2012026836-A1

Title: Proximity timer switch

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application claims priority based on the similarly entitled U.S. Provisional Patent Application Ser. No. 616/400,745 filed Aug. 2, 2010 naming Lucian Scripca and Valentina Scripca, the entire disclosure of which is hereby incorporated by reference. 
    
    
     REFERENCES CITED 
     Referenced by 
     U.S. Patent Documents 
     
       
         
           
               
               
               
             
               
                   
               
             
            
               
                 4,131,872 
                 August 1982 
                 Kearns; William F. 
               
               
                 2,333,688 
                 November 1943 
                 Shepard, Jr. 
               
               
                 3,031,644 
                 April 1962 
                 Hisserich et al. 
               
               
                 3,065,455 
                 November 1962 
                 Roth 
               
               
                 3,597,754 
                 August 1971 
                 Lerner 
               
               
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                 3,881,353 
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                 Fathauer 
               
               
                 4,260,980 
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                 4,290,126 
                 September 1981 
                 McFadyen et al. 
               
               
                   
               
            
           
         
       
     
     FIELD OF INVENTION 
     This invention relates to proximity switches and timer switches, particularly timer switches, which get activated by an object which enters a given range of proximity and stays in that range for a given period of time. 
     BACKGROUND OF THE INVENTION 
     The prior art, as exemplified in U.S. Pat. Nos. 4,131,872, 2,333,688, 3,031,644, 3,065,455, 3,597,754, 3,729,702, 3,881,353, 4,260,980, 4,263,665, 4,290,126 contains a number of automated devices which measure or detect the proximity to an object, or have a delay between the detection of an object and the actuation of a switch, or both. In the present invention the activation switch is turned on only if an object is detected at a precise distance, or range of distances, from the proximity timer switch, for a precise amount of time. If the object moves out of the range, before the time ran out, the unit does not turn on the activation switch. This invention applies best as a security device, where an access way which was left open unintentionally, will closed automatically after a period of time, and even more specifically, the invention applies better to older garage doors, where chances are they are left open after the car was driven out, leaving open access to the house. 
     SUMMARY OF THE INVENTION 
     The invention is summarized in a proximity timer switch which sends out a signal when it detects an object in a given range of proximity for a given period of time. The proximity timer switch has a momentary switch which, when activated, pauses the proximity timer switch indefinitely as long as the object is detected in the given range. Activating the momentary switch again, causes the proximity timer switch to run again. When the proximity timer switch was paused and the object moved out of the range, the proximity timer switch starts running again. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic representation of the way the proximity timer switch works: A burst of sonic waves, also known as ping, ( 6 ) is released by the proximity timer switch ( 1 ) and travels outwards, in a cone shaped wave until reflected back ( 7 ), also known as echo, by an object ( 2 ) or ( 3 ). The proximity timer switch ( 1 ) calculates the distance to the object by multiplying the speed of sound in the air by half of the time from when the ping is sent until the echo is detected. 
           D=V (sound)*( T echo− T ping)/2
 
       Where: 
       D is the distance from the proximity timer switch ( 1 ) to the object ( 2 ) or ( 3 ),
 
Techo is the time when the returning wave ( 7 ) is detected,
 
Tping is the time when the wave ( 6 ) was generated from the proximity timer switch
 
Vsound is the speed of sound in the air, approximately 343 meters per second.
 
       If the calculated value of the distance D falls in between DMIN and DMAX, DMIN&lt;D&lt;DMAX, then the object ( 2 ) is confirmed to be located inside the active zone ( 8 ). The proximity timer switch repeats the procedure at set period of time, delta t, for a set number of times N. The condition for the proximity timer switch to activate is that the condition DMIN&lt;D&lt;DMAX is satisfied N times, or every time it measures the distance to the object must be between DMIN and DMAX. If the object is, or moves outside the active zone ( 3 ), all measurements are ignored, or deleted. 
       All above determinations are made under the assumption that the measurements are made inside the sonic wave&#39;s cone of propagation. 
         FIG. 2  represents the block schematic of a possible implementation of the proximity timer switch, comprised of a power supply ( 9 ), an LED signaling block ( 10 ), an acoustic annunciator ( 11 ), a general on/off switch, a acoustic transducer ( 13 ), the logic control circuit ( 14 ), a user input block ( 15 ), an optional delay switch ( 16 ), and the output relay ( 17 ) with its contacts ( 18 ). The main building blocks are: 
       The acoustic transducer ( 13 ) with the role of generating the acoustic wave, ping, when driven by a corresponding input signal and generating an electric signal when detecting an acoustic wave, echo, 
       The logic control circuit ( 14 ), which provides all the sonar functions, does all the calculations to determine if the condition for detection are satisfied, takes input from the user, measures the power 
       The rest of the blocks are, and not limited to: 
       The power supply ( 9 ), does the conversion from the existing standard power supplies, such as battery or wall outlet, to the exact voltages needed by the electronic circuits in the proximity timer switch, 
       The optical signaling block ( 10 ), comprised of light sources, such as light emitting diodes (LEDs), light bulbs or liquid crystal displays (LCDs), which signal to the user the different states in which the proximity timer switch is, such as, abort mode, run mode, alert mode, and other modes, 
       The acoustic annunciator block ( 11 ), sends audible signals in accordance to different states which need to get the user&#39;s attention, such as low battery, alert before activating the output relay, push button feedback and more, 
       The on/off switch is optional and switches off the unit, to preserve power when not in use, 
       The push button ( 15 ), takes input from the user to switch between run and abort modes, with other possible functions to be implemented as needed, 
       The optional delay switch ( 16 ), gives the user a means to adjust the delay of the unit, 
       The output relay activates an external process when the detection of the object met the distance and time requirements, meaning the object was detected always inside the active zone during the delay time. 
         FIG. 3  depicts the proximity timer switch ( 19 ) used as an automatic garage door closer. The proximity timer switch ( 19 ) monitors the garage door ( 22 ) which is pulled open by the garage door opener ( 20 ). In this example, the screw ( 23 ) rotates, moving the slider ( 21 ) which is attached to the last panel of a segmented garage door. The door opens or closee guided by the rail ( 25 ). The two contacts of the proximity timer switch ( 19 ) are connected to the garage door opener ( 20 ) open/close contacts by a pair of wires ( 26 ). Once the garage door is detected in the active range of the proximity timer switch ( 19 ) for a given amount of time, it will activate the output relay of the proximity timer switch, causing the garage door opener ( 20 ) to close the garage door ( 22 ). All the other ways the garage door opener is activated, like push button on the wall and remote control are not affected by the proximity timer switch, the latter just adding a new security feature to it. More, the light barrier and the pressure detection security systems are still in effect. 
         FIG. 4  is one of many possible operational program flowcharts that can be embedded in the logic control circuit of the proximity switch, allowing the invention to function as an automatic garage door closer. Not present in this figure, and needed for explaining the flowchart is a user input device, like a push button for example, that will force an interrupt routine to be performed. The proximity timer switch is the vast majority of the time in Sleep mode, this way a very long battery life can be achieved. Periodically a Wakeup from sleep activates the battery check routine. If the battery has enough charge a distance measurement is done. If the battery is discharged, an audible signal is generated, until the battery gets replaced. The distance which has been measured determines if an object, in this case the garage door, is located inside the active zone of the proximity timer switch. If an object is detected, and the push button has not been activated, the distance measurement is done again in case the object is still in the active zone, as described in  FIG. 1 , an audible signal is generated a certain amount of times and the output relay is activated, closing the garage door. If, at any time, the push button is activated, the interrupt routine sets an Abort flag which will drive the program to Sleep mode as long as the object is in the active zone. This function allows one to force the garage door to stay open. The Abort flag can be reset by activating the push button or by closing the garage door, meaning the object in not detected in the active zone anymore. 
         FIG. 5  represents one of the many possible implementations of the proximity timer switch schematic diagram. The schematic can be better described by the main functional blocks with the corresponding attached components. The logic block is built around the micro-controller U 2 . The logic block is designed to execute the majority of functions with the least number of interface circuits, in order to minimize the overall cost. Along this line, the micro-controller U 2  generates the ultrasonic signal used to drive the ultrasonic transmitter Tx, receives and processes the echo detected by the ultrasonic receiver Rx, measures the energy level of the battery VI in conjunction with the circuit Q 1 , Q 2 , R 2 , R 3 , R 4  and R 6 , drives the optical enunciators D 5  and D 4 , drives the audible annunciator Buzz, and drives the output relay RLY 1 . The power supply is regulated by the low quiescent current voltage regulator U 4 , filtered by the capacitors C 1 , C 2  and protected for reverse polarity by the diode D 3 . The push button  51  generates an interrupt in the program flow in order to deactivate the output relay. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     As illustrated in  FIG. 1  through  FIG. 5  the invention is embodied in a proximity timer switch acting as an automatic garage door closer. 
     The proximity delay switch ( 1 ) in  FIG. 1  transmits a burst of ultrasonic sound (ping) in  FIG. 1  through the air. The wave ( 6 ) in  FIG. 1  propagates ahead until it reaches an obstacle ( 2 ) in  FIG. 1 . and is reflected back (echo) in  FIG. 1  to the proximity delay switch ( 1 ) in  FIG. 1 . 
     The distance from the proximity delay switch and the obstacle ( 2 ) in  FIG. 1  is calculated multiplying the speed of sound in the air, Vs=343.2 m/s (in normal condition of temperature, pressure and humidity), by half the time (ts) that took the ultrasonic wave to go from the proximity delay switch ( 1 ) in  FIG. 1  to the object and back ( 7 ) in  FIG. 1 : 
         D= ½ Vs*ts  
 
     The scope of this invention is to signal when the object ( 2 ) in  FIG. 1  is situated between a minimum distance D MIN ( 5 ) in  FIG. 1  and a maximum distance D MAX ( 4 ) in  FIG. 1 , or it is located inside the active detection zone ( 8 ) in  FIG. 1  for a given period of time. In the case of the preferred embodiment, the garage door closer, the proximity of the object would signify the garage door being opened, and the period of time would allow the garage door to stay open for a period of time in which the car can safely enter or exit the garage. To exceed this time means either the garage door was intentionally left open, or the garage door was forgotten open. When the garage door is intentionally left open, the user must suspend the garage door closer&#39;s function by pressing a switch. The garage door closer will then wait for another button press, or for the garage door to close once in order to re-start monitoring the proximity. When the object of the detection is situated in an area outside the active zone, the garage door closer is not signaling the presence of the object, or comes out of the suspend mode. 
     The proximity delay switch has a logic control circuit that works according to the flow chart depicted in  FIG. 4  as follows: most of the time, the circuitry is in sleep mode, to conserve energy, in this case battery life. Periodically, the logic control circuitry comes out from sleep mode, and performs a cycle of operations. The battery state of charge is checked, and if the battery is low, an audible signal is transmitted, to prompt the user to replace the battery with a fresh one. If the battery charge checks good, the proximity timer switch performs a distance measurement to the closest object in front of it. The suspend or abort switch, if pressed, sets an abort flag, at any time in the cycle. If an object, in this case the garage door, is inside the active zone, or open, and the abort flag is not set, a delay is activated, after which, if the garage door is still open, the garage door is closed, the abort flag is reset, and the unit goes into sleep mode. During the cycle, if the abort flag is set, the unit goes into sleep mode performing only the battery check. 
     The proximity timer switch main functional blocks are the logic control circuit, usually a micro-controller,  FIG. 2  ( 14 ), programmed to perform the logic functions described by the flowchart in  FIG. 4 . A power supply,  FIG. 2  ( 9 ), converts the voltage provided by the standard supply, like a battery, adaptor or mains, into the proper voltage levels needed by the circuit. The sonar,  FIG. 2  ( 13 ) generates the ultrasonic wave burst (ping) and converts the ultrasonic reflected wave (echo) into an electric signal, further processed by the logic control unit and converted into a number representing the distance to the nearest object in front of the sonar. LEDs of different colors  FIG. 2  ( 10 ) are turned on and off by the logic control circuit and signal to the user at certain time intervals the state of the suspend flag, whether the unit is active or in suspend mode, as an example, flashing green for active and flashing red for suspended mode. The buzzer  FIG. 2  ( 11 ), signals by means of audible sound either the fact that the garage door is about to close, a beep per second for 10 seconds, followed by two beeps per second on the last five seconds, and also the buzzer signals if the battery is low, by means of short beeps, every time the circuit wakes up from sleep mode. The push button in  FIG. 2  ( 15 ), when pressed places the unit into suspend mode. A delay switch  FIG. 2  ( 16 ), provides a manual way to adjust the time interval in which the garage door is allowed to remain open. The contacts in  FIG. 2  ( 18 ) of output relay in  FIG. 2  ( 17 ) are connected in parallel with the push button wires in  FIG. 3  ( 26 ) coming from the garage door opener main unit  FIG. 3  ( 20 ). A main on/off switch in  FIG. 2  ( 12 ) allows turning off the unit&#39;s power. For reference in  FIG. 3  is depicted a typical garage door with the proximity timer switch (garage door closer) attached to it, where ( 19 ) is the proximity timer switch facing the garage door ( 22 ). The ultrasonic wave burst ( 24 ) periodically is looking for the door. Other elements are the garage door closer chain or in this case screw ( 23 ) and the shuttle ( 21 ), physically connected to the garage door which rolls guided by the side tracks ( 25 ). 
     The electronic schematic diagram in  FIG. 5  depicts a simple and inexpensive way of implementing the proximity timer switch. A microcontroller U 2 , holds in the program memory the logic functionality depicted in the flowchart in  FIG. 4 . The power from the battery (BAT) is converted by the voltage regulator U 4  into 5VDC (VDD). Periodically, the battery monitor circuit Q 2  and  01  applies a load to the battery and sends the voltage to an analog to digital converter, in this circuit, part of the microcontroller U 2 . The sonar is built around the 44 kHz ultrasonic transducers, Tx and Rx, and the related circuitry. The signaling elements are the red LED (LEDR), the green LED (LEDG) and the Buzzer (Buzz). The suspend switch is  51  and the output relay is RLY 1 . The microcontroller U 2  sends an electric signal of 44 kHz to the transistor Q 3  which drives the ultrasonic transducer Tx generating an ultrasonic sound wave (ping), after further applied to the microcontroller analog to digital converter. The program calculates the distance to the object and makes the appropriate decisions, in conjunction with the signals received from the suspend switch and battery status circuit and the length of time the object has been detected. 
     Following is the listing of the main function saved in the microcontroller program memory, that is governing the proximity timer switch. The code is written in the C programming language.