Patent Document

FIELD OF THE INVENTION  
       [0001]     The present invention relates to wireless communication devices associated with vehicle tires for the purposes of reporting tire conditions.  
       BACKGROUND OF THE INVENTION  
       [0002]     As vehicles become more complex, vehicle designers change more and more parameters to modify performance and improve safety. One parameter that may be modified to change performance is the pressure within the tires of the vehicle. Unintended changes in the pressure within the tires of the vehicle may cause unwanted performance variations. These performance variations may include not only fuel consumption variations, but also safety concerns. Several efforts have been made to allow monitoring of the pressure in vehicle tires. In addition to merely monitoring the pressure in the tires, there is also a need to communicate the data from the monitoring to a location where the information may be used.  
         [0003]     Because of the rotation of the tires, wire-based solutions to the communication issue are impractical. The pressure monitor must be positioned on, and preferably inside, the tire itself such that the rotation of the tire precludes a wire-based communication link. Wireless solutions do offer many advantages and several systems have been proposed. In a typical solution, a transponder may be is positioned within the vehicle and coupled to a pressure sensing device. An interrogator wirelessly queries the transponder and the transponder replies with information derived from the pressure sensor.  
         [0004]     Because of differing vehicle designs, it is advantageous to have differing transponder designs. Having more transponder designs allows designers more options when integrating the transponders into vehicles and better designs may be the end result. To date, there has been a shortage of teachings in ways to distribute the interrogator within a vehicle. Likewise, how the transponder responds is a parameter of the sensing system that may be changed depending on the needs of the interrogator. Thus, providing a dual or multi-mode transponder may provide benefits to the designer.  
       SUMMARY OF THE INVENTION  
       [0005]     The present invention relates to use of a wireless communication device on a tire for monitoring tire conditions and the reporting of these tire conditions using an interrogation device. Monitoring of tire conditions on a vehicle may be performed when the vehicle is in rest or in motion. Special considerations must be made when using an interrogation reader on a vehicle to detect tire conditions via a transponder or RFID associated with a tire. The transponder on the tire may not always be in range of the interrogation reader during the tire&#39;s rotation when the vehicle is in motion. Two aspects of the present invention are designed to give vehicle designers more options when using interrogators and transponders to monitor tire pressure in vehicles. The last aspect introduces additional functionality into the transponder.  
         [0006]     A first aspect of the present invention involves distributing the interrogator throughout the vehicle in various configurations to give designers flexibility in laying out vehicle components. In a first embodiment, the interrogator is in the wheel well along with enough processing power to determine the tire pressure from the data received from the transponder. The output of the interrogator is sent to the vehicle control system for use thereby. Power is sent to the interrogator therefrom.  
         [0007]     In a second embodiment, power is sent from the vehicle control system, and the interrogator sends back a baseband signal that the vehicle control system then processes to determine the pressure of the tire.  
         [0008]     In a third embodiment, only an antenna is positioned in the wheel well. The modulated signal from the transponder is received and directed to the vehicle control system that performs all the processing.  
         [0009]     A second aspect of the present invention relates to how the transponder associated with the tire is interrogated. Due to electromagnetic emission concerns, the interrogator may be relatively low powered. If, for example, the interrogator were positioned in the wheel well of the vehicle, the transponder might not respond when the transponder was in the bottom half of the tire&#39;s rotation. Thus, to secure a proper response, save power and time, or reduce emissions, it may be desirable to interrogate the transponder only when the transponder is in the top half or a portion of its rotation. This aspect of the present invention determines where the transponder is during the tire rotation, and then queries the transponder only when the transponder is proximate to the interrogator.  
         [0010]     Exemplary techniques to determine the location of the transponder involve interfacing with the vehicle control system to learn the orientation of the wheel and empirically determining the location and interfacing with the vehicle control system to track its location with speed changes. Coupled with this aspect are some structural variations in the antenna structure designed to promote a more efficient communication between the transponder and the interrogator.  
         [0011]     A third aspect of the present invention provides a dual mode transponder that responds in a different manner based on the type of interrogation signal received. In a first mode, the transponders operate in a contention access protocol and allow data downloads thereto in the event that the transponders have memory associated therewith. The contention-based access allows a single interrogator to address multiple transponders concurrently. The transponder may enter a second mode based on the type of signal that the transponder is receiving. In an exemplary embodiment, if the transponder enters an RF field for a predetermined period of time, but the RF field does not have an amplitude modulation (AM) data modulation scheme, the transponder transmits readings from its pressure sensor and a checksum as rapidly as possible for as long as the RF field is sufficient.  
         [0012]     Those skilled in the art will appreciate the scope of the present invention and realize additional aspects thereof after reading the following detailed description of the preferred embodiments in association with the accompanying drawing figures. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]     The accompanying drawing figures incorporated in and forming a part of this specification illustrate several aspects of the invention, and together with the description serve to explain the principles of the invention.  
         [0014]      FIG. 1  illustrates a vehicle equipped with tires for pressure sensing according to an exemplary embodiment of the present invention;  
         [0015]      FIG. 2  illustrates a tire equipped with a transponder and a pressure sensing device according to an exemplary embodiment of the present invention;  
         [0016]      FIGS. 3A-3C  illustrate three embodiments of a distributed interrogator according to one aspect of the present invention;  
         [0017]      FIG. 4  illustrates an exemplary side elevational view of an interrogator and a transponder interacting in a wheel well;  
         [0018]      FIG. 5  illustrates a first embodiment of an antenna structure for use with the present invention;  
         [0019]      FIG. 6  illustrates a second embodiment of an antenna structure for use with the present invention;  
         [0020]      FIG. 7  illustrates as a flow chart a first embodiment of transponder location on the part of the interrogator;  
         [0021]      FIG. 8  illustrates a schematic diagram of an interrogator and inputs thereto for the purposes of transponder location;  
         [0022]      FIG. 9  illustrates as a flow chart a second embodiment of transponder location on the part of the interrogator; and  
         [0023]      FIG. 10  illustrates as a flow chart an exemplary embodiment of the two-mode functionality of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0024]     The embodiments set forth below represent the necessary information to enable those skilled in the art to practice the invention and illustrate the best mode of practicing the invention. Upon reading the following description in light of the accompanying drawing figures, those skilled in the art will understand the concepts of the invention and will recognize applications of these concepts not particularly addressed herein. It should be understood that these concepts and applications fall within the scope of the disclosure and the accompanying claims.  
         [0025]     The present invention is directed at providing options for designers of vehicles and tires. Specifically, in the effort to provide more information to a vehicle controller, tire pressure or other tire conditions may be sensed and reported through a wireless connection comprising a transponder and an interrogator. The present invention presents several variations of these elements for additional functionality and design opportunities when providing an interrogation system to interrogate tire conditions on a vehicle.  
         [0026]      FIG. 1  illustrates a vehicle  10  with a body  12  and tires  14  as is conventional. The body  12  may delimit wheel wells  16  within which tires  14  are substantially located during vehicle operation. A vehicle controller  18  may be associated with the vehicle  10 , and is contained within the body  12 . A transponder  20  may be positioned within one or more of the tires  14  and wirelessly communicate with a respective interrogator  22  positioned at least partially within the respective wheel wells  16 , or other location proximate to the tires  14  sufficient to establish wireless communication with the transponder  20 .  
         [0027]      FIG. 2  illustrates a more detailed view of a tire  14  with the associated transponder  20 . The tire  14  may comprise a rim  24  and a tread element  26  as is well understood. Positioned within the tire  14  is the transponder  20 , which may comprise an antenna  28  and a wireless communication circuit  30 . A tire condition sensor  32  may be associated with the transponder  20 . The tire condition sensor  32  may be a pressure sensor, a temperature sensor, humidity sensor, tread sensor, or any other type of sensor that measures or detects an environmental condition relating to the tire  14  or a condition about the tire  14  itself. The wireless communication circuit  30  and the tire condition sensor  32  may be integrated into a single unit as needed or desired. Further information about the wireless communication circuit  30 , the antenna  28 , and the tire condition sensor  32  may be found in U.S. Pat. Nos. 5,181,423; 4,529,961; 5,473,938; 6,087,930; 5,977,870; 5,562,787; 5,463,374; 5,844,130; 5,541,574; and 4,160,971; and U.S. patent application Ser. No. ______, filed Jun. 6, 2002, entitled “Capacitive Pressure Sensor,” all of which are hereby incorporated by reference. In an exemplary embodiment, the wireless communication circuit  30  comprises the ONETAG™, as shown in U.S. patent application Ser. No. 09/678,271, filed Oct. 3, 2000, entitled “Wireless Communication Device and Method,” or MICROINSERT™, as shown in U.S. patent application Ser. No. 09/618,505, filed Jul. 18, 2000, entitled “Wireless Communication Device and Method,” both of which are hereby incorporated by reference, and sold by the assignee of the present invention. These devices are compatible with the INTELLITAG interrogators sold by INTERMEC of 6001 36th Avenue West, Everett, Wash. 98203-9280. U.S. Patent Application No. 60/378,384 entitled “RFID Temperature Device and Method,” discloses a temperature sensor, which is incorporated herein by reference in its entirety. An example of a humidity sensor is disclosed in U.S. Pat. No. 6,342,295 entitled “Moisture Sensor,” incorporated herein by reference in its entirety. An example of a tread sensor is disclosed in U.S. Pat. No. 6,028,503 entitled “System for the Detection of Tire Tread Separation,” incorporated herein by reference in its entirety. Note that any type of sensor may be used as the tire condition sensor  32 .  
         [0028]     The interrogator  22  is schematically illustrated in  FIGS. 3A-3C . An interrogator  22  may comprise an antenna  34 , a demodulator  36 , and a baseband processor  38 . Further, filters, mixers, and the like may be present as is well understood. To provide additional design options for the designer of the vehicle  10 , the interrogator  22  may be distributed in a number of different embodiments. As illustrated in  FIG. 3A , the antenna  34 , the demodulator  36 , and the baseband processor  38  are all integrated into a single unit and positioned in a wheel well  16 . Processed data and power flow to and from the vehicle controller  18  and the baseband processor  38  over the link  40 .  
         [0029]      FIG. 3B  illustrates an embodiment, in which the baseband processor  38  is integrated into the vehicle controller  18 , but the antenna  34  and the demodulator  36  are integrated into a single unit and positioned in the wheel well  16 . The demodulated, but unprocessed signal and power are passed to and from the vehicle controller  18  and the demodulator  36  over the link  42 .  
         [0030]      FIG. 3C  illustrates a third embodiment, in which the baseband processor  38  and the demodulator  36  are integrated into the vehicle controller  18 . Only the antenna  34  is positioned in the wheel well  16 . Raw, undemodulated signals and power pass to and from the antenna  34  and the baseband processor  38  over the link  44 .  
         [0031]     Together, these three embodiments provide a variety of options for designers to use when incorporating interrogators into vehicles. As noted earlier, provision of more options provides more flexibility for the designers and improves the likelihood that an acceptable design may be located that meets the design criteria of the designer. Note that these three embodiments do not match the INTERMEC device, but the components of the INTERMEC device could be split into such an arrangement by one of ordinary skill in the art.  
         [0032]     With this background of hardware, some of the other aspects of the present invention may now be discussed. In the past, some systems have continuously interrogated the transponder  20  with the interrogator  22 . This wastes power, and raises electromagnetic compatibility (EMC) issues, as well as FCC compliance issues. As vehicles become more complicated, with more circuitry associated therewith, the dangers of crosstalk and fugitive radio frequency (RF) emissions becomes more serious. Thus, the ability to interrogate selectively may give the designers more options in addressing these concerns. Selective interrogation may also prevent the interrogator  22  from erroneously interrogating transponders  20  that are positioned on nearby vehicles or transponders  20  positioned on other tires  14  of the vehicle  10 . While all of these are concerns during the design phase, another concern is that of speed. Typically, the interrogator  22  must transmit initially a data sequence to initialize a reading from the tire condition sensor  32 . This is followed by a reception of the data from the transponder  20 . This query and response occupy a certain amount of time. If the transponder  20  is not in the field of view when the first byte of the initial data sequence is sent, the rest of the message is wasted, and the transponder  20  has to remain in the field of view until another message is sent, potentially doubling the amount of time needed and halving the vehicle speed at which the transponder  20  can be read. Accurate synchronization ensures that only one cycle of the protocol is needed to read the data, and this allows for maximum speed.  
         [0033]     As illustrated in  FIG. 4 , the interrogator  22  generates an electromagnetic field  46 , which in an exemplary embodiment is a lobe-shaped field. The precise frequency of the field  46  is a design choice, but is typically an RF field. It may be desirable to interrogate the transponder  20  when the transponder  20  is within the field  46 . Thus, the circumferential position  48  of the transponder  20  must be determined, so that the interrogation may begin proximate in time to the transponder  20  entering the field  46 . Two techniques for determining the circumferential position  48  of the transponder  20  are illustrated in  FIGS. 7 and 9 . From the circumferential position  48 , the time window to initiate interrogation of the transponder  20  may be derived.  
         [0034]     Armed with the time window in which it may be appropriate to interrogate the transponder  20 , modifications may be made to an antenna structure such that focused interrogation occurs. The basic objective is to optimize communication between the interrogator  22  and the transponder  20  such that nearly continuous communication is provided. One way to achieve this is through the use of multiple antennas. If the multiple antennas transmit simultaneously, the radiation pattern of the group may become distorted with interference induced nulls.  
         [0035]     Since the location and speed of the transponder  20  is known, the antenna need only communicate with the transponder  20  over a narrower arc of rotation of the wheel  14 . Further, multiple antennas may be fired sequentially based on the known position and speed, thereby addressing any distortion concerns. Two such antenna structures  70  are illustrated in  FIGS. 5 and 6 . In the first embodiment of  FIG. 5 , a plurality of transmit antennas  72  are used in conjunction with a single receive antenna  74 . In the embodiment shown, five transmit antennas  72 A- 72 E are illustrated, although it should be appreciated that fewer or more transmit antennas  72  may be used if needed or desired. The transmit antennas  72 A- 72 E generate corresponding electromagnetic lobes  76 A- 76 E. The lobes  76 A- 76 E are narrow and extend sufficiently far to reach the expected location of the transponder  20 . The transponder  20  responds with an electromagnetic signal that is received by the receive antenna  74 . Because the reflected signal from the transponder  20  will typically have a signal to noise ratio of 20 dB to 50 dB, the lobe structure of the receive antenna  74  need not be as precise as that of the transmits antennas  72 .  
         [0036]     A second embodiment, illustrated in  FIG. 6 , of antenna structure  70  arranges a plurality of dual function antennas  78 A- 78 E about the wheel well  16 . Each antenna  78  both transmits and receives an electromagnetic signal with a focused lobe  80 . As the transponder  20  moves through the field of view of the antennas  78 , the antennas may sequentially alter functions to achieve the maximum downlink, transmit, critical path, adequate uplink and receive. For example, initially the first antenna  78 A may be in a transmit mode while second antenna  78 B was in a receive mode. The remaining antennas  78 C- 78 E may be disconnected. As the transponder  20  moves in front of the second antenna  78 B, then the second antenna  78 B is used to transmit, while first and third antennas  78 A and  78 C are used to receive. The remaining antennas  78 D and  78 E remain disconnected. The transponder  20  may then move into lobe  80 C, effectively being in front of third antenna  78 C, so third antenna  78 C is used to transmit and second and fourth antennas  78 B and  78 D are used to receive. First and fifth antennas  78 A and  78 E are disconnected. This process continues until the transponder  20  leaves the lobe  80 E, or the last lobe of the antenna structure  70 .  
         [0037]      FIG. 7  illustrates a first embodiment of transponder  20  location determination. It is possible that the present invention may be carried out while the vehicle  10  is not operating, however it is assumed for the purpose of explanation that the present invention is performed while the vehicle is operating. Thus, the process starts when the vehicle  10  starts (block  100 ). Initially, before acquisition of the transponder  20  by the interrogator  22 , the interrogator  22  emits the electromagnetic field  46  (block  102 ).  
         [0038]     The transponder  20  enters the field  46  as a function of the rotation of the tire  14  (block  104 ). Alternatively, the transponder  20  may be in the field  46  as soon as the field  46  is activated. In either event, the transponder  20  responds to the interrogation signal (block  106 ) as is well understood. The interrogator  22  or the vehicle controller  18  may determine the time elapsed during which the transponder  20  responded (block  108 ). In the event that the transponder  20  started in the field  46 , or to reduce the likelihood of a spurious first signal, the determination may wait until the first edge of response is detected after an absence of a response. That is, the determiner (the vehicle controller  18  or the interrogator  22 ) confirms that there is no response at first, and the interrogator  22  remains active and waits until a response has been detected before beginning to measure the period of time during which there is a response. When an edge is detected indicating that a signal is being received at the interrogator  22 , the waiting ends and the measuring begins.  
         [0039]     From the time determination and the size of the wheel  14 , a circumferential velocity  48  may be determined (block  110 ). The size of the wheel  14  determines the arc through which the transponder  20  passes. The portion of the arc that is within the field  46  may be divided by the time calculated and the circumferential velocity is determined thereby. Once the absence of a response is detected, the interrogator  22  may be deactivated (block  112 ). With the circumferential velocity and the size of the wheel  14 , the vehicle controller  18  or the interrogator  22  may calculate an estimated time until the transponder  20  re-enters the field  46  (block  114 ). The portion of the arc that is outside the field  46  is divided by the circumferential velocity  48  to provide the time estimate.  
         [0040]     The interrogator  22  may be turned on or reactivated immediately prior to the estimated time of reentry (block  116 ). In a preferred embodiment, an absence of a response would be detected and confirmed, and then the transponder  20  would enter the field  46 , resulting in a response. This likewise accommodates acceleration and deceleration within reason. It is contemplated that the phrase “immediately prior to the estimated time of re-entry” is to be interpreted as allowing for acceleration at the highest rate possible by the vehicle  10 .  
         [0041]     A determination is made if the vehicle  10  has been turned off (block  118 ). If the answer is no, the process repeats. If the answer is yes, the process ends (block  120 ). Note that the precise order of events need not occur as indicated and that rearrangements of the process are contemplated.  
         [0042]     The second embodiment, described in  FIG. 7 , may require additional hardware. To explain this additional hardware, reference is made to  FIG. 8 , in which the vehicle controller  18  is shown schematically connected to a plurality of inputs. Specifically, the vehicle controller  18  is connected to an odometer  50 , a tachometer  52 , an axle sensor  54 , a transmission sensor  56 , and/or a fuel injection computer  58  as well as the interrogator  22 . From the various inputs, the vehicle controller  18  may determine with some precision the rotation of a wheel  14 , and from knowledge already in the possession of the vehicle controller  18 , deduce the location and speed of the transponder  20 . Note that not all the inputs need be used, and some require more processing than others to derive the rotational speed of the wheels  14 . Other sensors or inputs could also be used if needed or desired.  
         [0043]     Additionally, a memory  60  may be associated with the vehicle controller  18  in which data may be stored, such as the last location of the transponder  20  prior to the engine being turned off.  
         [0044]     With these inputs, the second embodiment of turning on and off the interrogator  22  depending on the location of the transponder  20  may be explicated with reference to  FIG. 9 . The vehicle  10  starts (block  150 ) such as when the ignition is turned on. The vehicle controller  18  references the memory  60  to determine the last circumferential location of the transponder  20  (block  152 ). This may have been determined and entered by factory calibration, by the mechanic who last rotated and/or changed the tires  14 , or by storage from the last time the vehicle  10  was operated. Alternatively, this may be determined by empirically, such as through the method of  FIG. 7 .  
         [0045]     The vehicle controller  18  or the interrogator  22  determines if the transponder  20  is within the area of field  46  when the field  46  is active (block  154 ). If the answer is no, the vehicle controller  18  may reference the inputs such as the axle sensor  54  or the transmission sensor  56  to determine the location of the transponder  20 , and determines from its present location and the speed of the vehicle when the transponder  20  will enter the area of the field  46  (block  156 ). After the determination of block  156 , or if block  154  is answered positively, the interrogator  22  is activated (block  158 ). If the transponder  20  was outside of the area of field  46 , then the interrogator  22  is turned on immediately prior to the expected arrival of the transponder  20  within the area of the field  46 .  
         [0046]     The interrogator  22  receives a response signal from the transponder  20  while the transponder  20  is within the field  46  (block  160 ). The vehicle controller  18  or the interrogator  22  determines if the transponder  20  has left the field  46  (block  162 ). If the answer is no, the process repeats. If the answer is yes, then the interrogator  22  is turned off (block  164 ).  
         [0047]     The vehicle controller  18  determines if the vehicle has been turned off (block  166 ). If the answer is no, the process repeats as indicated. If the answer is yes, the process ends (block  168 ).  
         [0048]     Again, as noted above, the exact order of the method need not be as linear as indicated and variations in the order of the steps are contemplated as well as performing some steps concurrently instead of consecutively.  
         [0049]     A third aspect of the present invention relates to how the transponder  20  may have at least a dual mode functionality depending on the type of RF field to which the transponder  20  is subjected. During manufacturing, many transponders  20  and tires  14  may be proximate one another. In such instances, it may be desirable to operate in a first mode such that the transponder  20  responds in a first fashion so that a single interrogation  22  can interrogate a transponder  20 , such as during manufacturing of the tire  14 . However, this slows down the response time of each transponder  20  since the interrogator  22  must distinguish between different transponders  20 . However, when the transponder  20  is installed on a tire  14  that is in operation of a vehicle  10 , it may be desirable to operate in a second mode so that the transponder  20  can interrogator  22  and the transponder  20  can communicate more quickly since the transponder  20  is no longer competing for bandwidth against other transponders  20  and thus the transponder  20  responds in a second fashion. Other modes could also be incorporated into the transponder  20  as needed or desired. Reference is made to  FIG. 10 , wherein a flow chart illustrating this dual modality is presented.  
         [0050]     Initially, the transponder  20  enters an RF field (block  200 ). This may be an RF field  46  or a field such as is present in a manufacturing environment. The transponder  20  determines if there is an amplitude modulation (AM) component to the field (block  202 ). Alternatively, the presence of a known byte will serve the same role, in which case the step becomes the equivalent step of the transponder  20  determines if a known byte is present. If the answer is no, there is no AM component (thus indicating that the transponder is in a field analogous to field  46 ), the transponder  20  begins to transmit pressure data derived from the tire condition sensor  32  and a checksum with as much speed and bandwidth as is available (block  204 ). The transponder  20  then determines if the transponder  20  is still in the field  46  (block  206 ). If the answer is no, the process ends (block  208 ) until the transponder  20  detects a new RF field (block  200 ). If the answer to block  206  is yes, the transponder  20  determines if the field  46  has changed (block  210 ). If the answer to block  210  is no, the process repeats as indicated. If the answer to block  210  is yes, then the transponder may switch modes (block  212 ).  
         [0051]     If, however, the determination at block  202  indicates that there is an AM component to the field (or there is a known byte present), then the transponder  20  may enter a contention access protocol mode (block  214 ). This may include a time division multiplex system, a frequency division multiplex system, or the like as needed or desired. An exemplary contention access protocol is that based on the Carrier Sense Multiple Access (CSMA) protocol commonly used for Ethernet connections.  
         [0052]     The transponder  20  transmits information and data when authorized (block  216 ) and this transmission conveys the information requested by the field that caused the transponder  20  to enter this mode (block  218 ). The transponder  20  may make a determination that the transponder  20  is still in the field (not shown) and/or a determination that the field has changed (block  220 ). If the field has changed, the transponder  20  may switch modes (block  212 ). If however, the field has not changed, the transponder  20  may repeat the process as indicated.  
         [0053]     While the above has been termed as a test for the presence of an AM field or a known byte, equivalently, a test for the presence of a continuous RF field, or one modulated by a continuous clock signal could also be used to trigger entry into the mode where the transponder  20  sends data from the tire condition sensor  32  continuously and as quickly as possible. The clock possibility is an interesting variation in that it allows the transponder  20  to use the clock frequency (known to be accurate) as a reference against which the transponder  20  can measure the output of the tire condition sensor  32 .  
         [0054]     Note that some of the determination steps are not explicit, and the presence or absence of a field may cause the determination. This is especially true when the transponder  20  is a passive device rather than an active device. However, the transponder  20 , and particularly the wireless communication circuit  30 , may include the intelligence and memory to have complex functionality if needed or desired. Also note that the present invention may include the transfer of information of any kind concerning the tire  14 , including pressure, and this information is not limited to pressure information.  
         [0055]     Those skilled in the art will recognize improvements and modifications to the preferred embodiments of the present invention. All such improvements and modifications are considered within the scope of the concepts disclosed herein and the claims that follow. It should be noted that that although pressure of the tire  14  is monitored, that other tire conditions in lieu of or in addition to pressure may be monitored using the present invention as well.

Technology Category: 7