Patent Publication Number: US-8981934-B2

Title: Loss prevention system

Description:
RELATED APPLICATION 
     This application claims the benefit of U.S. patent application Ser. No. 61/422,426 filed on Dec. 13, 2010, the entirety of which is hereby incorporated by reference. 
    
    
     BACKGROUND 
     Businesses frequently possess small valuable articles that are intended to remain in a single room for indefinite periods of time. For example, a doctor&#39;s office may keep a digital thermometer in an exam room. Unfortunately, it can be relatively easy for such articles to be lost. Such articles can be lost in various ways. For example, small valuable articles can be stolen or misplaced. For example, a person could steal a digital thermometer simply by putting the digital thermometer in a pocket and walking out of an exam room where the digital thermometer is meant to stay. In another example, a digital thermometer could easily become concealed in the bed linens of a patient&#39;s hospital room and be accidentally taken out of the hospital room when the bed linens are changed. 
     SUMMARY 
     A loss prevention system is provided. The theft and loss prevention system comprises a protected article and a receiver. The protected article and the receiver are located in the same room. The protected article comprises a transmitter that emits an infrared signal. The infrared signal has a carrier frequency that is modulated to encode a digital signature. The receiver detects infrared signals. The receiver performs an alarm action if the receiver does not detect within a rolling time window an infrared signal having the carrier frequency that is modulated to encode the digital signature. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates an example embodiment of a loss prevention system. 
         FIG. 2  is a block diagram that illustrates example details of a transmitter in the loss prevention system. 
         FIG. 3  is a block diagram that illustrates example details of a receiver in the loss prevention system. 
         FIG. 4  is a flowchart that illustrates an example operation for installing the loss prevention system. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  illustrates an example embodiment of a loss prevention system  100 . As illustrated in the example of  FIG. 1 , the loss prevention system  100  comprises a protected article  102 . The protected article  102  can be a wide variety of different types of articles. For example, the protected article  102  can be a portable medical device, such as a digital thermometer, a digital otoscope, a vital signs reader, a patient monitor, a set of surgical equipment, a set of dental tools, or another type of portable medical device. In another example, the protected article  102  can be a personal computer, a laptop computer, a tablet computer, a handheld computer, a computer peripheral device, a printer, a projector, a camera, a book, a safe, a tool, or another type of article. 
     The protected article  102  is located in a room  104 . The room  104  can be a variety of different types of room. For example, the room  104  can be a medical exam room, an operating room, a recovery room, an observation room, and/or an intensive care unit room. In another example, the room  104  can be an office, a conference room, a hotel room, a bathroom, a workshop, a shed, or another type of room. The room  104  can be located inside a building. 
     The protected article  102  comprises a transmitter  106 . The transmitter  106  periodically emits an infrared signal  108 . The infrared signal  108  has a carrier frequency. In various embodiments, the infrared signal  108  has various carrier frequencies. For example, the infrared signal  108  can have a carrier frequency of 20 kHz. 
     The transmitter  106  modulates the carrier frequency of the infrared signal  108  to encode a digital signature into the infrared signal  108 . In this way, the infrared signal  108  carries the digital signature. The digital signature is a series of digits. In various embodiments, the digital signature can contain various numbers of digits. For example, the digital signature can be a series of 32 binary digits. In another example, the digital signature can be a series of 10 decimal digits. 
     The loss prevention system  100  also comprises a receiver  110 . The receiver  110  is mounted at a fixed position within the room  104 . The receiver  110  detects infrared signals, such as the infrared signal  108 . Because the infrared signal  108  is in the infrared part of the electromagnetic spectrum, the infrared signal  108  does not significantly penetrate the walls of the room  104 . Consequently, infrared detectors located outside the room  104  do not receive the infrared signal  108 . However, the infrared signal  108  tends to reflect off the walls of the room  104 . As a result, the receiver  110  can detect the infrared signal  108  even if there is not a direct line of sight between the protected article  102  and the receiver  110 . 
     The receiver  110  stores one or more digital signatures. For example, the receiver  110  can store the digital signature of the transmitter  106 . Each of the digital signatures is associated with a time window. In various embodiments, the timer windows have various lengths. For example, the timer windows can have lengths of ten seconds. In another example, the timer windows can have lengths of twenty seconds. When the receiver  110  detects an infrared signal having the carrier frequency, the receiver  110  determines whether the infrared signal carries one of the digital signatures. If the receiver  110  determines that the infrared signal carries one of the digital signatures, the receiver  110  resets a time window for the digital signature. 
     The receiver  110  performs an alarm action if the receiver  110  does not detect an infrared signal that carries the digital signature within the time window for the digital signal. For example, the time window for a given digital signature can be ten seconds. In this example, the receiver  110  performs an alarm action if the receiver  110  does not receive an infrared signal that carries the given digital signature within ten seconds of a most recent time that the receiver  110  received an infrared signal that carried the given digital signature. 
     In various embodiments, the receiver  110  can perform various alarm actions. For example, performing the alarm action can comprise emitting an audible alarm, such as a siren. In another example, performing the alarm action can comprise flashing a light. In the example of  FIG. 1 , the loss prevention system  100  comprises an alarm control center  112 . In the example of  FIG. 1 , performing the alarm action comprises sending an alarm signal from the receiver  110  to the alarm control center  112  via a communications network  114 . 
     The alarm control center  112  comprises one or more physical locations where people and/or computing devices receive alarm signals and determine how to respond to the alarm signals. In different embodiments, the alarm control center  112  can be in a different building than the room  104  or the same building as the room  104 . The alarm control center  112  can be operated by an entity that uses the room  104  or by a third party service provider. The communications network  114  can comprise various types of communications networks, such as a public-switched telephone network, a wireless computer networking network, a wired broadband network connection, the Internet, a local-area network, or another type of communications network. 
       FIG. 2  is a block diagram that illustrates example details of the transmitter  106  in the loss prevention system  100 . In various embodiments, the protected article  102  may or may not be designed for use with the transmitter  106 . For example, the protected article  102  can be originally designed and manufactured to include the transmitter  106 . In another example, the protected article  102  can be originally designed to be used with the transmitter  106  and the transmitter  106  is added to the protected article  102  after the protected article  102  is initially sold. In yet another example, the protected article  102  is not originally designed to be used with the transmitter  106 . 
     In various embodiments, the transmitter  106  can be attached to the protected article  102  in various ways. For example, the transmitter  106  can be incorporated within an exterior housing of the protected article  102 . In another example, the transmitter  106  can be attached to an exterior of the protected article  102  with an adhesive, screws, bolts, rivets, welds, tape, or other fasteners. 
     As illustrated in the example of  FIG. 2 , the transmitter  106  comprises a storage module  200 , transmitter circuitry  202 , a power supply  204 , and an emitter  206 . The storage module  200  stores a digital signature. In various embodiments, the digital signature can become stored in the storage module  200  in various ways. For example, the digital signature can be hard coded into the circuitry in the storage module  200 . In another example, the storage module  200  is an electrically-erasable programmable read-only memory (EEPROM). In this example, the digital signature can be stored onto the storage module  200  when the transmitter  106  is manufactured, or afterward. In some embodiments where the digital signature is stored onto the storage module  200  when the transmitter is manufactured, each different transmitter made by a given manufacturer stores a unique digital signature. In other embodiments where the digital signature is stored onto the storage module  200  when the transmitter is manufactured, transmitters for different product types have different digital signatures, but transmitters for the same product type have the same digital signature. In another example, an end user of the protected article  102  can store the digital signature on the storage module  200 . 
     The transmitter circuitry  202  retrieves the digital signature from the storage module  200  and outputs electrical signals to the emitter  206 . The electrical signals cause the emitter  206  to emit the infrared signal  108 . In some embodiments, the emitter  206  emits the infrared signal  108  in all directions. In other embodiments, the emitter  206  emits the infrared signal  108  in only some directions. As discussed above, the infrared signal  108  has a carrier frequency that is modulated to encode the digital signature stored in the storage module  200 . 
     In various embodiments, the transmitter circuitry  202  outputs electrical signals that cause the emitter  206  to emit the infrared signal  108  at various intervals. For example, the transmitter circuitry  202  can cause the emitter  206  to emit the infrared signal  108  once every second. In another example, the transmitter circuitry  202  can cause the emitter  206  to emit the infrared signal  108  once every three seconds. 
     The power supply  204  provides electrical power to the storage module  200 , the transmitter circuitry  202 , and the emitter  206 . In various embodiments, the power supply  204  is implemented in various ways. For example, the power supply  204  can be implemented as a rechargeable battery. In this example, the rechargeable battery can be separate from the main power supply of the protected article  102 . In another example, the power supply  204  can be the main power supply of the protected article  102 . The main power supply of the protected article  102  can be a battery or a main power supply of a building that contains the room  104 . 
       FIG. 3  is a block diagram illustrating example details of a receiver  110 . As illustrated in the example of  FIG. 3 , the receiver  110  has a mounting member  300 . The mounting member  300  acts to mount the receiver  110  at a stationary location within the room  104 . In various embodiments, the mounting member  300  can have various forms. For example, the mounting member  300  can be a bracket that mounts the receiver  110  to a wall of the room  104 . In another example, the mounting member  300  can be a portion of an exterior housing of the receiver  110  that defines a loop through which a screw, nail, or other fastener can pass. This fastener is attached to a wall or other surface in the room  104 . In yet another example, the mounting member  300  is a flat area in the exterior housing of the receiver  110 . In this example, the flat area of the external housing can help the receiver  110  rest stably on a flat surface within the room  104 . 
     Furthermore, the receiver  110  comprises a signature storage module  302 . The signature storage module  302  stores one or more digital signatures. In various embodiments, the signature storage module  302  is implemented in various ways. For example, the signature storage module  302  can be implemented as an EEPROM, a solid state memory module (e.g., a Flash memory unit), or another type of computer-readable storage medium. 
     In various embodiments, the digital signatures can be stored onto the signature storage module  302  in various ways. For example, the receiver  110  can comprise a programming control  304  as shown in  FIG. 3 . When a user of the receiver  110  activates the programming control  304 , the signature storage module  302  stores the digital signatures carried by each infrared signal detected by the receiver  110  within a given time period. Thus, when the user installs the receiver  110  in the room  104 , the user can activate the programming control  304  to cause the receiver  110  to start expecting to detect infrared signals carrying the digital signatures of each protected article in the room  104 . 
     In various embodiments, the user can activate the programming control  304  in various ways. For example, the programming control  304  can be a button. In this example, the user activates the programming control  304  by pressing on the programming control  304 . In another example, the programming control  304  can be a switch. In this example, the user activates the programming control  304  when the user flips the switch. 
     In another example, the receiver  110  can comprise a network interface  306  as shown in  FIG. 3 . The network interface  306  is a device that enables the receiver  110  to communicate with other computing devices via the communications network  114 . In this example, the network interface  306  receives digital signatures from another computing device via the communications network  114 . For instance, the network interface  306  can receive the digital signatures from a computing device at the alarm control center  112 . When the network interface  306  receives a digital signature, the signature storage module  302  stores the digital signature. 
     In other embodiments, digital signatures can be stored onto the signature storage module  302  in other ways. For example, the receiver  110  can comprise a keypad (not shown). In this example, the signature storage module  302  stores digital signatures entered by a user via the keypad. 
     The signature storage module  302  also stores time data associated with each of the digital signatures stored in the signature storage module  302 . In various embodiments, the time data have various forms. For example, the time data associated with a digital signature can indicate a last time that the receiver  110  detected an infrared signal that carries the digital signature. In another example, the time data associated with a digital signature indicates a time before which the receiver  110  must receive an infrared signal carrying the digital signature to prevent the receiver  110  from performing an alarm action. In yet another example, the time data associated with a digital signature can count up the amount of time that has passed after the receiver  110  last received an infrared signal carrying the digital signature. 
     Furthermore, the receiver  110  comprises a sensor  308 . The sensor  308  detects infrared signals, such as the infrared signal  108 . When the sensor  308  detects an infrared signal, the sensor  308  outputs an electrical signal to a time reset module  310  within the receiver  110 . In various embodiments, the electrical signal encodes different information about the infrared signal. For example, the electrical signal outputted by the sensor  308  can have a voltage waveform that represents the modulated carrier frequency of the infrared signal. In another example, the sensor  308  can demodulate the carrier frequency. In this example, the electrical signal outputted by the sensor  308  can have a voltage waveform that represents information modulated onto the carrier frequency. 
     The time reset module  310  determines whether the information carried by the detected infrared signal (i.e., the information modulated onto the carrier frequency of the infrared signal) is one of the digital signatures stored in the signature storage module  302 . To determine whether the information carried by the detected infrared signal is one of the digital signatures stored in the signature storage module  302 , the time reset module  310  reads the digital signatures from the signature storage module  302 . 
     If the time reset module  310  determines that the information carried by the detected infrared signal is a given one of the stored digital signatures, the time reset module  310  resets the time window associated with the given digital signature. In various embodiments, the time reset module  310  resets the time window associated with the given digital signature in various ways. For example, the time reset module  310  can store time data indicating a current time into the signature storage module  302 . In another example, the time reset module  310  can store time data that indicates a time before which the receiver  110  must receive an infrared signal carrying the digital signature to prevent the receiver  110  from performing an alarm action. 
     The receiver  110  also comprises an alarm module  312 . The alarm module  312  determines whether the receiver  110  has detected infrared signals carrying the stored digital signatures within the time windows for the stored digital signatures. In various embodiments, the alarm module  312  determines in various ways whether the receiver  110  has detected an infrared signal carrying a given one of the digital signatures within a time window for the given digital signature. For example, the signature storage module  302  can store a time data that indicates a last time that the receiver  110  detected an infrared signal carrying the given digital signature. In this example, the alarm module  312  determines whether an amount of time between the current time and the time indicated by the time data is greater than the time window for the given digital signature. In another example, the signature storage module  302  can store time data that indicates a time before which the receiver  110  must detect another infrared signal carrying the digital signature. In this example, the alarm module  312  determines whether a current time is after the time indicated by the time data. 
     If the alarm module  312  determines that the receiver  110  has not detected an infrared signal carrying a given one of the stored digital signatures within the time window for the given digital signature, the alarm module  312  performs an alarm action. In various embodiments, the alarm module  312  can perform various alarm actions. For instance, in the example of  FIG. 3 , the receiver  110  comprises a siren  314 . When the alarm module  312  performs an alarm action, the alarm module  312  can output electrical signals that cause the siren  314  to emit an audible sound. Furthermore, when the alarm module  312  performs an alarm action, the alarm module  312  can cause the network interface  306  to send an alarm message to a computing device in the alarm control center  112  via the communications network  114 . 
     The time reset module  310 , the alarm module  312 , and the network interface  306  can be implemented in various ways. For example, the time reset module  310 , the alarm module  312 , and/or the network interface  306  can be comprise one or more integrated circuits. In another example, the time reset module  310 , the alarm module  312 , and/or the network interface  306  can comprise one or more circuits laid out on a circuit board. 
       FIG. 4  is a flowchart illustrating an example operation  400  for installing the loss prevention system  100 . As illustrated in the example of  FIG. 4 , the operation  400  begins when an installer mounts the receiver  110  in the room  104  ( 402 ). As discussed above, the installer can mount the receiver  110  in the room  104  in various ways. After the installer mounts the receiver  110  in the room  104 , the installer connects the receiver to the communications network  114  ( 404 ). In various embodiments, the installer can connect the receiver to the communications network  114  in various ways. For example, the installer can plug a network cable into the receiver  110 . In another example, the installer can configure the receiver  110  to use a wireless signal to connect to the communications network  114 . 
     Furthermore, the installer places one or more protected articles (e.g., the protected article  102 ) in the room  104  ( 406 ). Each of the protected articles has a transmitter that emits infrared signals that carry digital signatures. After the installer places the protected articles in the room  104 , the installer activates the transmitters of the protected articles ( 408 ). In various embodiments, the installer can activate the transmitters in various ways. For example, the installer can activate the transmitters using on/off switches on the transmitters. In another example, the installer can activate the transmitters by installing batteries in the transmitters. In yet another example, the installer can activate the transmitters by connecting the power supplies of the transmitters to main power supplies of the protected articles. 
     The installer can then program the receiver  110  to perform alarm actions if the receiver  110  does not detect within rolling time windows infrared signals having carrier frequencies that are modulated to encode the digital signatures of the transmitters ( 410 ). As discussed above, the receiver  110  can be programmed in various ways. 
     The various embodiments described above are provided by way of illustration only and should not be construed as limiting. Those skilled in the art will readily recognize various modifications and changes that may be made without following the example embodiments and applications illustrated and described herein. For example, the operations shown in the figures are merely examples. In various embodiments, similar operations can include more or fewer steps than those shown in the figures. Furthermore, in other embodiments, similar operations can include the steps of the operations shown in the figures in different orders.