Antenna and wireless deadbolt sensor

An antenna for reception and transmission of signals within an enclosure. The antenna includes a first lead for connection to a printed circuit board and a second lead. A plurality of vertical members extend in parallel to one another and spaced a predetermined distance apart. Each vertical member has a first end and a second end. A plurality of horizontal members is provided. Each horizontal member extends alternately between first ends of a pair of adjacent vertical members and second ends of a next pair of adjacent vertical members forming a connection between said first lead and said second lead.

FIELD OF THE INVENTION

An antenna which can operate in a constrained or compact enclosure.

BACKGROUND OF THE INVENTION

Many devices operate within a constrained or compact enclosure from which a user may need to obtain information regarding the operation of the device. Without the ability to obtain information directly from the device inside the enclosure, it is necessary to have the information transmitted to the user or at times to transmit data to the device. It is also desirable for the user to be able to monitor and/or control the operation of the device from a remote location. Without remote monitoring capability, a user may not have the ability to monitor and/or control the operation of the device.

Conventional methods of monitoring activity within such a constrained or compact enclosure have only allowed for the use of a chip antenna or a physically short antenna that is not tuned to a desired frequency.

An advantageous antenna would be formed as one of a dipole or monopole and be raised away from a printed circuit board allowing for improved transmission and reception of signals over conventional chip antennas.

Advantageously, the antenna would be able to receive and transmit signals from within the enclosure enabling a user to securely and remotely query the status of a device within the enclosure, for example, a property entrance-door deadbolt lock, a set top box, a gateway, etc., using, for example, a cell phone that can be located substantially anywhere in the world without a need to subscribe to a commercial security service. A remotely situated user using conventional Application software (Apps) for Windows, Android, or iOS is able to receive the status or operational parameters of the device, for example by detecting when a deadbolt lock is engaged in a door frame or when it is retracted from the door frame based on a queried command, detecting a status of a set top box or remotely programming the set top box to record a program, etc. The queried command may be applied by wireless communication via a Graphical User Interface installed on a Smartphone or Personal Computer such as a Laptop, Desktop, or Notepad that may be located in the vicinity of the device or at a remote location that may be far from the device. Additionally, the sensor may be used in a variety of Home Automation applications. The sensor has a unique advantage of being lower in cost and providing better performance than chip antennas and also allows for use in very small spaces.

In a further advantageous feature, the antenna can be employed in any Wi-Fi, ZigBee or Bluetooth application. Further, the antenna can be employed in any number of devices where it would operate in a constrained enclosure such as a set-top box or gateway. In a further exemplary use, when used with a deadbolt sensor, the antenna can be used to receive command signals for remotely locking and unlocking, e.g. activating and deactivating, the deadbolt lock.

For example, when operating with a device in an enclosure, the antenna may be connected to a wireless transceiver/transmitter. Responsive to output signals such as from a sensor, the wireless transceiver/transmitter may periodically transmit a first wireless signal via the antenna conforming to a Bluetooth Low Energy (BLE) protocol that may contain information derived from the output signal. A BLE-ZigBee bridge device responsive to the BLE wireless signal may periodically store information related to the device. The bridge device may additionally be responsive to a second wireless signal conforming to the ZigBee protocol containing a request for information. The bridge device may transmit stored information using a third wireless signal conforming to the ZigBee protocol at a power level that is higher than a power level of the first wireless signal. The third wireless signal may be applied to a gateway device that conveys the stored information via the antenna to, for example, a remote user via, for example, a wide area network such as the Internet.

Advantageously, the antenna, the sensor, the BLE wireless transceiver and a battery that energizes the BLE wireless transceiver are installed together as a single unit that is inserted into a compact enclosure. They may also be displaced together, during operation, as a single unit in the enclosure.

Advantageously, reliability of the device may be improved by informing the user of any malfunction by providing error detection capability that includes redundancy, transmitting a signal indicative of the error detection using the antenna. The antenna improves the transmission and reception of signals by the device by increasing the transmission range, allowing for operation as either a monopole or dipole, minimizing interference from a printed circuit board and allowing for tuning to a desired frequency.

SUMMARY OF THE INVENTION

The antenna is etched on a substrate which is connectible to a printed circuit board positioned within an enclosure. The antenna is formed having first and second leads with a number of bends therebetween. The first and/or second leads are connectable to a wireless transceiver on the printed circuit board. The antenna may be tuned to a desired frequency and used in conjunction with the transmitter to transmit a signal from or related to the device. The antenna may also receive signals from a user for controlling or polling the device.

DETAILED DESCRIPTION

FIG. 1illustrates a dipole antenna10according to a preferred embodiment for use in a constrained or compact enclosure for receiving information for and transmitting information from or concerning a device within the enclosure. The antenna10is etched onto a substrate20connected to and extending from a printed circuit board22. The dipole antenna10includes a first lead12for a first pole11of the dipole antenna10and a first lead14for a second pole13of the dipole antenna10. The first lead12for the first pole11of the dipole antenna10and the first lead14for the second pole13of the dipole antenna10each extend along opposing sides of the substrate20. A second lead15of the first pole11and a second lead17of the second pole13extend below the printed circuit board22for connection to a transceiver T1, discussed hereinafter, on the printed circuit board22. Positioned between the first and second leads12,15and14,17of each of the first and second poles are a plurality of vertical members16and a plurality of horizontal members18. The plurality of vertical members16and plurality of horizontal members18connect in alternating fashion forming a continuous path between the first and second leads. The plurality of vertical members16extend in parallel and are spaced from one another between the first lead12,14and the second lead15,17of each of the corresponding first and second poles. The plurality of horizontal members18each connect a respective pair of adjacent vertical members together to form a continuous path between the first and second leads12,14and15,17of each of the corresponding first and second poles. A first vertical member may be connected at a first end either directly or through a connection with a horizontal member to the first lead12,14. A first end of one of the plurality of horizontal members may be connected between a second end of the first vertical member and a second end of an adjacent vertical member. Another of the plurality of horizontal members may be connected between a first end of the adjacent vertical member and a first end of a further vertical member. This pattern continues to form a continuous path between the first and second leads as shown inFIG. 1. When connected in this manner, the resulting antenna has a form similar to a meandering oscillatory shape such as a square wave pattern. A bend is formed at each connection between a vertical member and horizontal member. The bend preferably forms a substantially right angle, e.g. between 80°-100°, although the angle between vertical and horizontal members may be anywhere between substantially 0° and 180°. As electrons accelerate when they change direction, each of the bends of the antenna through which the electrons must travel adds to the acceleration resulting in increased radiation and thus an increased transmission range for the antenna. The number of vertical members and horizontal members and thus the number of bends forming the antenna is dependent on the size of the enclosure and the size of a substrate able to fit within the enclosure. Additionally, the length of the vertical and horizontal members may be increased or decreased in order to include a predefined number of bends forming the antenna having a size able to fit within a desired enclosure. Preferably, the antenna will be of a size able to fit within the enclosure and having a maximum number of bends. Performance of the antenna may also be improved by maximizing the number of bends. The length of the antenna is preferably selected based on being a quarter-wavelength of the carrier frequency; in the exemplary case the carrier frequency used was 2.4 GHz. However, any method for selecting the length of the antenna which achieves the desired results may be used. A preferred total path length for the antenna is substantially equal to ½ the transmit and receive wavelength.

The substrate20on which the antenna10is etched is shown extending perpendicular to the printed circuit board22. However, the substrate20may extend at any angle from the printed circuit board22able to raise the antenna from the printed circuit board. The angle at which the substrate20extends may be dependent on the size and dimensions of the enclosure. The substrate20on which the antenna10is etched raises the antenna away from the printed circuit board22allowing for improved transmission and reception of signals over chip antennas. The antenna is described as being etched on the substrate. However, any manner of attaching the antenna to the substrate may be used.

The antenna10may be preferably developed for 2.4 GHz-carrier frequency operation. However, the antenna can be tuned to any desired frequency. The substrate is preferably a flex FR4 substrate. The Flex FR4 substrate is flexible and thus can be bent to conform to the shape of the printed circuit board to which it is connected. However, any substrate able to be bent and shaped to fit within a small tight space may be used. The substrate should also have a thickness sufficient for allowing the antenna to be etched thereon. The forming of the antenna in the meandering oscillatory shape such as a square wave pattern allows for elongation of the antenna resulting in an increased transmission range. The flexibility of the substrate and its connection to the printed circuit board allows the antenna to be fit into a constrained enclosure that would otherwise only allow for a chip antenna or physically short antenna that, disadvantageously, may not be amenable for being tuned to a desired frequency. The substrate is able to raise the antenna away from the circuit board thus minimizing interference with elements on the circuit board. This allows for improved transmission and reception of signals over that possible with conventional chip antennas10. Measurements have shown an increase in transmission and reception range from a factor of 1.9 to a factor of 3.0 over conventional chip antennas.

The antenna10was preferably developed for 2.4 GHz carrier frequency operation utilized on a flex FR4 substrate. However, the antenna10can operate at any desired frequency and etched on any flexible substrate able to fit within the desired enclosure and connect with a printed circuit board. The antenna10provides an increase range over chip antennas using Bluetooth Low-Energy and Zigbee transceivers. Additionally, the printed circuit board can be of any shape able to fit in the desired enclosure and the substrate and thus the antenna can be bent to the shape of the printed circuit board to which it is attached thus adding to the usefulness of the antenna.

FIG. 2illustrates a monopole antenna100according according to a preferred embodiment for use in a constrained or compact enclosure for receiving information for and transmitting information from or concerning a device within the enclosure. The antenna100is etched onto a substrate20connected to and extending from a printed circuit board22. The monopole antenna100includes a first lead120. A second lead150extends below the printed circuit board22for connection to a transceiver on the printed circuit board22. Positioned between the first and second leads120,150are a plurality of vertical members160and a plurality of horizontal members180. The plurality of vertical members160and plurality of horizontal members180connect in alternating fashion forming a continuous path between the first and second leads120,150. The plurality of vertical members160extend in parallel and are spaced from one another between the first lead120and the second lead150. The plurality of horizontal members180each connect a respective pair of adjacent vertical members together to form a continuous path between the first and second leads120and150. A first vertical member may be connected at a first end either directly or through a connection with a horizontal member to the first lead120. A first end of one of the plurality of horizontal members may be connected between a second end of the first vertical member and a second end of an adjacent vertical member. Another of the plurality of horizontal members may be connected between a first end of the adjacent vertical member and a first end of a further vertical member. This pattern continues to form a continuous path between the first and second leads as shown inFIG. 2. When connected in this manner, the resulting antenna has a form similar to a square wave pattern. A bend is formed at each connection between a vertical member and horizontal member. The bend preferably forms a substantially right angle, e.g. between 80°-100°, although the angle between vertical and horizontal members may be anywhere between substantially 0° and 180°. As electrons accelerate when they change direction, each of the bends of the antenna through which the electrons must travel add to the acceleration resulting in increased radiation and thus an increased transmission range for the antenna. The number of vertical members and horizontal members and thus the number of bends forming the antenna is dependent on the size of the enclosure and the size of a substrate able to fit within the enclosure. Additionally, the length of the vertical and horizontal members may be increased or decreased in order to include a predefined number of bends forming the antenna having a size able to fit within a desired enclosure. Preferably, the antenna will be of a size able to fit within the enclosure and having a maximum number of bends. Performance of the antenna may be further improved by maximizing the number of bends. The total path length of the antenna is preferably selected based on being a half-wavelength of the carrier frequency; in the exemplary case the carrier frequency used was 2.4 GHz, which is common practice in antenna design. However, any method for selecting the length of the antenna which achieves the desired results may be used.

The substrate20on which the antenna100is etched is shown extending perpendicular to the printed circuit board22. However, the substrate20may extend at any angle from the printed circuit board22able to raise the antenna from the printed circuit board. The angle at which the substrate20extends may be dependent on the size and dimensions of the enclosure. The substrate20on which the antenna100is etched raises the antenna away from the printed circuit board22allowing for improved transmission and reception of signals over chip antennas. The antenna is described as being etched on the substrate. However, any manner of attaching the antenna to the substrate may be used.

The antenna100may be preferably developed for 2.4 GHz-carrier frequency operation. However, the antenna can be tuned to any desired frequency. The substrate is preferably a flex FR4 substrate. The flex FR4 substrate is flexible and thus can be bent to conform to the shape of the printed circuit board to which it is connected. However, any substrate able to be bent and shaped to fit within a small tight space may be used. The substrate should also have a thickness sufficient for allowing the antenna to be etched thereon. The forming of the antenna in the shape of a meandering oscillatory shape such as the square wave pattern allows for elongation of the antenna resulting in an increased transmission range. The flexibility of the substrate and its connection to the printed circuit board allows the antenna to be fit into a constrained enclosure that would otherwise only allow for a chip antenna or physically short antenna that, disadvantageously, may not be amenable for being tuned to a desired frequency. The substrate is able to raise the antenna away from the circuit board thus minimizing interference with elements on the circuit board. This allows for improved transmission and reception of signals over that possible with conventional chip antennas. Measurements have shown increase in transmission and reception range from a factor of 1.9 to a factor of 3.0 over conventional chip antennas.

The antenna100was preferably developed for 2.4 GHz carrier frequency operation utilized on a flex FR4 substrate. However, the antenna can operate at any desired frequency and etched on any flexible substrate able to fit within the desired enclosure and connect with a printed circuit board. The antenna100provides an increase range over chip antennas using Bluetooth Low-Energy and Zigbee transceivers. Additionally, the printed circuit board can be of any shape able to fit in the desired enclosure and the substrate and thus the antenna100can be bent to the shape of the printed circuit board to which it is attached thus adding to the usefulness of the antenna100.

FIG. 3shows the substrate20on which the antenna10,100is etched and the printed circuit board22to which the substrate20is connected encased within a sensor housing26. The sensor housing26is shaped to fit in the enclosure within which the device will operate. The sensor housing26shown inFIG. 3includes a pool40in which the printed circuit board22and substrate20are seated. The pool40is formed by a base30and a wall32extending from and at least partially around a periphery of the base30. Shown positioned on a side of the printed circuit board22opposite the base30is a sensor34. The sensor34senses information related to the device and provides an information signal to circuitry mounted on the printed circuit board22for transmission via the antenna. The sensor34, and printed circuit board22situated therebelow, is shown retained within the pool40by protrusions36extending from the wall32. The protrusions36are shown for purposes of example only. However, any device able to retain the sensor34, printed circuit board22and substrate20within the pool40may be used.

FIGS. 4A, 4B and 4Cillustrate different views of a deadbolt sensor assembly8embodying a preferred embodiment installed in a door jamb. Deadbolt sensor assembly8includes a sensor capable of being disposed in a cavity formed in a frame of a door for sensing a deadbolt position to generate an output signal that is indicative of when the deadbolt position is in the cavity in a lock position and when the deadbolt position is outside the cavity in an unlock position. A wireless transmitter T1, described hereinafter, is responsive to the sensor output signal and capable of being disposed in the cavity for transmitting a wireless signal containing information derived from the output signal. The wireless transmitter is mounted on the mounting surface or printed circuit board shown inFIGS. 1 and 2. A substrate20, as shown inFIGS. 1 and 2, extends from and is inclined to the mounting surface22. The substrate20surrounds a first portion of a periphery of the mounting surface22. A conductor10,100having a meandering oscillatory shape is formed on the substrate20thereby maximizing the length of the conductor10,100. The conductor10,100has a length greater than a length of a line antenna. The length of the conductor10,100is dependent upon a height and width of folds forming the meandering oscillatory shape. The total path length of the conductor10,100is preferably one-half the transmit and receive wavelength. The conductor10,100is coupled to the transmitter to form an antenna.

FIG. 4Aillustrates sensor assembly8and antenna according to a preferred embodiment, for use with a deadbolt42forming a lock in a door46. A deadbolt housing48defining a deadbolt cavity50in a door jamb or frame44receives deadbolt42, when deadbolt42is locked. Sensor housing26including sensor assembly8and antenna such as antenna10,100ofFIG. 1, 2is also received in cavity50ofFIG. 4A. However, instead of installing deadbolt housing48for forming cavity50, door jamb44may be drilled out to form cavity50. For example, it can be drilled out with ⅞ inch to 1 inch diameter spade to a depth of between 1 and ¼ inch to 1 and ½ inch. A diameter D2of cavity50may range from ⅞ inch to 1 inch.

FIG. 5illustrates an electrical circuit diagram for an exemplary sensor assembly8for use within an enclosure and connected to antenna10,100ofFIG. 1, 2for transmitting signals sensed by the sensor assembly8ofFIGS. 4A and 5. The sensor assembly8is received in the pool40ofFIG. 3. Sensor assembly8ofFIGS. 4A and 5includes sensors28aand28b. Sensors28aand28bcan be included in a manner not shown in sensor34ofFIG. 3. Sensor28aofFIG. 5includes a mechanically operated plunger switch S1. Plunger switch S1of sensor28ais not depressed when the device being monitored by the sensor assembly is disengaged, e.g. a deadbolt for unlocking a door is disengaged. When switch S1is not depressed, switch S1forms a non-conductive or open circuit. Conversely, plunger switch S1of sensor28ais depressed when the device is engaged, e.g. a deadbolt for locking a door is engaged. When switch S1is depressed, a current path is formed between its terminals.

A field effect transistor (FET) Q1has a first main current conducting terminal Q1athat is coupled to a corresponding terminal of switch S1and a second main current conducting terminal Q1bthat is coupled via a pull-up resistor R1to a supply voltage V provided by a battery B1such as a lithium coin battery. The other terminal of switch S1is coupled to a ground terminal G at 0V. Battery B1has a nominal voltage of 3.0 volts.

A System on Chip (SOC) U1, such as Texas Instruments CC2541, contains a processor and a 2.4 GHz Bluetooth low energy (BLE) transmitter-receiver or transceiver, which are not shown in detail. BLE is a wireless personal area network technology. SOC U1polls, in response to a periodic command, a port P0_6of SOC U1. The period or frequency in which SOC U1performs the polling operation is controlled, under normal operating conditions, by a BLE-ZigBee bridge device (not shown). Polling is accompanied in SOC U1by applying a control voltage via a port P0_2to a gate terminal of FET Q1to turn on FET Q1. When turned on, FET Q1couples pull-up resistor R1to port P0_6. When switch S1is depressed, switch S1couples port P0_6of SOC U1to ground terminal G. Consequently, a voltage of 0V is sensed at port P0_6when SOC U1polls port P0_6. The voltage of 0V, sensed at port P0_6by the processor of SOC U1, is indicative of the device being engaged, e.g. a deadbolt being engaged to lock a door.

Advantageously, FET Q1is turned on to activate detection of the status of switch S1only, during periodic intervals, when the aforementioned polling occurs. At other times FET Q1is turned off. This mode of operation is utilized in order to reduce discharge or depletion of battery B1. This feature is particularly important because battery B1is not connected to any battery charger. Yet, battery B1is required to serve for a long time without a need for frequent replacement service. If switch S1was turned on for as long as the device is in an engaged position, there would be an undesirable constant draw, for example, of approximately 30 micro-amps from battery B1via resistor R1.

As indicated before, switch S1is not depressed when the device is in a disengaged position, e.g. unlocking the door. When not depressed, switch S1is non-conductive. Therefore, FET Q1couples port P0_6to battery B1voltage V of 3V via pull-up resistor R1. Thus, SOC U1sensing the presence of battery B1voltage V at port P0_6is indicative the device being in a disengaged position.

Advantageously, redundant sensor28butilizes an infra-red (IR) proximity detector U2. Sensor28bfacilitates an error detection feature. An FET Q2has a first main current conducting terminal Q2athat is coupled both to a supply terminal U2aof proximity detector U2and to a current limiting resistor R2. A second main current conducting terminal Q2bof FET Q2is coupled to supply voltage V of battery B1. SOC U1applies a voltage to a port P0_7that is coupled to a gate terminal of FET Q2to turn on FET Q2for performing polling operation in proximity detector U2. Similarly to FET Q1, FET Q2is turned on to activate the detection associated with proximity detector U2only when the aforementioned polling occurs in sensor28b. At other times, FET Q2is turned off. This mode of operation that is similar to that applicable to FET Q1is utilized in order to reduce discharging battery B1.

Optical proximity detector U2operates in cooperation with an IR light emitting diode (LED) DS1. LED DS1is driven via current limiting resistor R2by FET Q2, when FET Q2is turned on for polling an output signal PRX of detector U2.

Optical proximity detector U2is an active optical reflectance proximity detector with an on/off digital output whose state is based upon the comparison of reflected IR light against a set threshold. LED DS1produces light pulses at a strobe frequency of, for example, 2.0 Hz, of which reflections from an element of the device being monitored, e.g. a front face of a deadbolt, reach a photodiode, not shown, of proximity detector U2and are processed by proximity detector U2analog circuitry, not shown. The rate detector U2detecting the proximity of the element of the device being monitored is controlled by a resistor R13. The average current drawn by detector U2in this exemplary embodiment is 5 micro-amps with proximity detection frequency of 2.0 Hz. A resulting most recent or current state of the detected proximity is developed at output signal PRX of detector U2that is polled by port P2_0of SOC U1. If the reflected light is above the detection threshold, proximity detector U2asserts an active-LOW output signal PRX to indicate the device is engaged, e.g. the deadbolt is in a locked position. Conversely, if the reflected light is below the detection threshold, proximity detector U2ofFIG. 2asserts a HIGH output signal PRX to indicate the device is disengaged, e.g. the deadbolt is in an unlocked position. The output signals are provided to a transceiver T1for transmission to a user via antenna10,100.

A pair of terminals RF_P and RF_N of SOC U1communicates Radio Frequency (RF) modulated signals transmitted/received by the BLE transceiver, not shown, of SOC U1in accordance with the BLE protocol. Terminals RF_P and RF_N of SOC U1are coupled to a corresponding pair of terminals, respectively, of an Impedance Matched RF Front End Differential Balun-Low Pass Filter integrated passive component T1. An output terminal of integrated passive component T1is coupled to antenna10,100for transmitting/receiving the RF signal associated with the BLE transceiver of SOC U1.

FIGS. 6A, 6B and 6Cprovide flow charts useful for explaining the operation of sensor assembly8ofFIG. 5for transmission of signals using antenna10,100. Similar symbols and numerals inFIGS. 5, 6A, 6B and 6Cindicate similar items or functions. Except as otherwise noted, sensor assembly8ofFIG. 5participates in each step referred to inFIGS. 6A, 6B and 6C. The flow charts ofFIGS. 6A, 6B and 6Cshow use of the antenna10,100with a sensor assembly8for sensing the position of a deadbolt. However, this operation is shown for purposes of example only and, in practice, the antenna of the present arrangement may be used to sense, control or monitor conditions and activities of any device positioned within an enclosure.

Under normal operation, a periodic command referred to in more detail later on, may be transmitted using a BLE wireless signal initiated, for example, in a BLE-ZigBee bridge device and received by the BLE transceiver of SOC U1via antenna10,100. Upon the occurrence of the aforementioned periodic command, SOC U1, operating in a so-called Sleep Mode prior to the occurrence of the aforementioned periodic command, performs a so-called Wake Up step100of the flow chart ofFIG. 6A. Next, SOC U1tests in a step105whether SOC U1has been initiated for the first time. If it had been initiated before, then SOC U1, in a step110, turns on or activates FET Q1for activating status checking of the deadbolt by SOC U1polling port P0_6that reads the state of switch S1. After polling port P0_6, SOC U1deactivates FET Q1.

Next, SOC U1, in a step115, turns on or activates FET Q2for checking the status of proximity detector U2by reading output signal PRX developed at port P2_0. Subsequently, in a step120, the reading of proximity detector U2output signal PRX is compared in the processor, not shown, of SOC U1with the reading of the previously obtained state of switch S1for providing error checking that is performed in a processor, not shown, of SOC U1. If the readings are consistent or verified in a step125, then, in a step126that is performed by a BLE-ZigBee bridge device, the state of the deadbolt, locked or unlocked, is transmitted via antenna10,100. Afterwards, in a step130, SOC U1returns to the so-called Sleep Mode.

If at step105, it is determined that SOC U1has been initiated for the first time, BLE-ZigBee bridge device306transmits a message via antenna10,100, in a step135of a calibration routine as shown inFIG. 6B, requesting the user activate deadbolt assembly8. Activation of deadbolt assembly8is performed by changing its current state, lock or unlock, to the other state. Then, SOC U1in a step140polls each of port P0_6and port P2_0and stores the state of each of switch S1and IR detector U2. Next, in a step145, SOC U1transmits a message to a user located next to the deadbolt requesting the user to change the state of deadbolt from its preceding locked or unlocked state to the opposite state. Following the changing of the state of deadbolt, SOC U1, in a step150, polls each of port P0_6and port P2_0and stores the state of each of switch S1and IR detector U2. This calibration process is used to confirm that each switch S1and proximity detector U2do indeed change state in response to the change of state of the deadbolt.

If the processor, not shown, in SOC U1, at step125ofFIG. 6A, determines that an error has occurred, SOC U1initiates an error routine shown in the flow chart ofFIG. 6C. In a step152, SOC U2reactivates FET Q1for reading at port P0_6the state of switch S1and reactivates FET Q2for reading the status of proximity detector U2by reading output signal PRX at port P2_0. Next, in a step155, the reading of proximity detector output signal PRX is compared to the reading of the state of switch S1. If the readings are consistent or verified, in a step160, then step126ofFIG. 6Afollows. Otherwise, BLE-ZigBee bridge device transmits an error message in a step165. Next, in a step170, SOC U1returns to the so-called Sleep Mode.

Other than antenna10,100and battery B1, the rest of the circuitry of sensor assembly8that is depicted inFIGS. 4A, 4B and 4Cis mounted on a first printed circuit board (PCB)25. The antenna10,100is mounted to a second PCB or substrate20as discussed with respect toFIGS. 1, 2 and 3. Battery B1and antenna10,100are shown mounted on the second PCB20that is connected to PCB25using pin standoffs or clips. However, the battery B1may be connected to the printed circuit board by any known manner. In the present exemplary embodiment, PCB25, PCB20and pin standoffs are contained in sensor housing26to form a structure having a length dimension, measured in the direction of the movement of deadbolt, of approximately ⅓ inch. Sensor housing26has an opening26bfor enabling deadbolt42to contact plunger switch S1ofFIG. 5of sensor28aofFIG. 4Awhen deadbolt42is engaged for locking door46.

As shown inFIG. 4A, a spring29has an end portion, remote from PCB20, which makes a sliding contact, without being fastened or immobilized, to a back wall48aof housing48. Spring29has an opposite end that is mechanically attached to PCB20. Thus, spring29is interposed between sensor assembly8and back wall48a. As explained later on, during installation, spring29and the structure of PCB25, PCB20and pin standoffs27are manually pushed into cavity50to remain there indefinitely.

The deadbolt should, preferably, have sufficient clearance relative to plunger switch S1ofFIG. 5so as not to contact switch S1when deadbolt is unlocked. Also, the deadbolt, preferably, should be able to contact plunger switch S1ofFIG. 5without causing the spring29to be fully compressed when deadbolt is locked.

Advantageously, battery B1ofFIG. 5, switch S1, detector U2and SOC U1are disposed on the structure formed by PCB25and PCB20that is connected to spring29ofFIG. 4B. Interposing spring29between wall48aof housing48and the structure formed by PCB25, PCB20and standoffs27, advantageously, provides a capability to displace together battery B1, switch S1, detector U2and SOC U1that are entirely contained in cavity50ofFIG. 4A. Displacing together battery B1, switch S1, detector U2and SOC U1ofFIG. 4Ais caused by the movement of deadbolt42. The flexing capability of spring29compensates for a particular travel distance selected for deadbolt42, a particular selected length of deadbolt42and a particular gap selected between door46and frame44. The compensation is obtained by different extent of compression/expansion of spring29when deadbolt42is moved from the unlock position to the lock position, and vice versa.

Advantageously, the ability of PCB25, PCB20and pin standoffs27to move together laterally in response to locking/unlocking deadbolt42by the operation of spring29avoids the need to adjust the position of sensor assembly8, during installation in door frame44. This feature makes sensor assembly8versatile for accommodating differences among travel distances and differences in lengths of different deadbolts similar to deadbolt42and also differences of corresponding gaps between a variety of door and door frame combinations such as between door46and door frame44.

Advantageously, packaging battery B1, Balun-Low Pass Filter integrated passive component T, SOC U1, IR detector U2and switch S1on the structure formed by PCB25, PCB20and pin standoffs27avoids the need for installing any part of moveable sensor assembly8externally to cavity50. Additionally, sensor assembly8can be manufactured in sizes to accommodate common industry standards. Thus, sensor assembly8and housing48require minimal or no modification of pre-existing combinations of door frame, door and deadbolt.

FIG. 4Billustrates a side view of the sensor assembly8ofFIG. 4Awhen it is separate from frame44and before being inserted into cavity50.FIG. 4Cillustrates a front view of the sensor assembly8ofFIG. 4B. Similar symbols and numerals inFIGS. 4A, 4B, 4C, 5, 6A, 6B and 6Cindicate similar items or functions.

Advantageously, sensor assembly8ofFIG. 4Aor sensor housing26is not firmly attached to any of the walls of cavity50. For example, spring29touches wall48awithout being firmly attached to it. Sensor assembly8as shown inFIG. 4Cincludes a group of 4 resilient legs47that are evenly distributed each 90 degree angular interval around its circumference52. Each leg47is formed of a flexible material to form an arc-shaped spring. When sensor assembly8ofFIG. 4Bis still not installed in cavity50ofFIG. 4A, a curved portion of each leg47ofFIG. 4Bis tangent to circumference52ofFIG. 4Chaving a center axis49and a diameter D1. Diameter D1is larger than diameter D2of cavity50ofFIG. 4A, when sensor assembly8ofFIG. 4Bis still not installed in cavity50ofFIG. 4A.

Advantageously, during installation, sensor assembly8ofFIG. 4Bis inserted into cavity50ofFIG. 4Amerely by a manual sliding push. Consequently, flexible legs47ofFIG. 4Bare flexed such that distance D1ofFIG. 4Ccontracts, in a manner not shown, and becomes equal to distance D2ofFIG. 4A.

Axis49ofFIG. 4Balso represents a direction of displacement of sensor28a, for example. When sensor assembly8is installed inside cavity50, each of flexible legs47ofFIG. 4Bproduces a radial force, not shown, having a component in a direction perpendicular to a direction of axis49ofFIG. 4B.

Advantageously, flexible legs47are capable of, advantageously, hindering sensor system8ofFIG. 4Afrom falling out of or separating from cavity50when deadbolt42is in the unlock position. As indicated before, flexible legs47ofFIG. 4Benable insertion of sensor assembly8, during installation into cavity50ofFIG. 4A. Thus, as explained before, installing sensor assembly8in cavity50is simply done by merely pushing it into cavity50that can be accomplished by substantially untrained user.

FIGS. 7A and 7Bshow radiation patterns measured for the antenna of the preferred embodiment. These figures show relative spatial performance and illustrate the measured range of the antenna.FIG. 7Aillustrates the relative strength of the field as a function of direction along the XY plane andFIG. 7Billustrates the relative strength of the field as a function of direction along the XZ plane. As previously discussed, these figures show an increase in transmission and reception range when compared to the measured strength of a chip antenna from a factor of 1.9 to a factor of 3.0.