Patent Document

FIELD 
     The present invention relates generally to electronic communications devices, and more particularly to mobile hand held communications devices. 
     BACKGROUND 
     Mobile communications devices are increasingly popular in our society. It is popular to talk on mobile handsets while driving. Many users of mobile handsets would like a simple and convenient way to make a mobile telephone call easily while driving. One attempt to solve this problem is a hands-fee car kit. 
     A hands-free car kit is an electronic device, which will enable a person to have a conversation on a mobile call without having to hold a mobile handset. The hands-free car kit is a speaker that is loud enough to be heard from several feet away and over the noise of a typical car, combined with a microphone designed to receive a human voice from several feet away. Typically the microphone has some filtering function for filtering out common noises of a car. The hands-free car kit may include a cradle for holding the mobile handset. Many hands-free car kits also supply power to the mobile handset. 
     Some hands free car kits allow the user to push a button on the unit to operate in privacy mode. Privacy mode allows the user to switch modes so that the mobile handset microphone and speaker are active and the hands-free car kit microphone and speaker are deactivated. This prevents others in the car from hearing what the caller is saying to the person in the vehicle. If the hands-free car kit microphone and speaker are active the unit is in hands-free mode. 
     While many hands-free car kits are external to the mobile handset, it will be clear to one of skill in the art that a mobile handset could have a hands-free car kit mode. In hands-free car kit mode the mobile handset would have a built in speaker loud enough to be heard from several feet away and a microphone designed to receive a human voice from several feet away. 
     On many current hands-free car kits with privacy mode, if privacy becomes an issue, the user is required to engage a switch known as a privacy button and pick up the mobile handset for normal use. The reason that a person uses a hands free car kit is to minimize the complexity of operating a mobile handset while driving. Pushing a button to enter and exit privacy mode adds unnecessary complexity to the task of conducting a mobile call while driving. 
     Some hands-free car kits enter privacy mode automatically when the user picks up the mobile handset by using a mechanical switch. When a mechanical switch is used the switch is typically placed in the cradle, requiring wiring to be placed in the cradle. Additionally, a mechanically switch can more easily become contaminated and fail to function properly. 
     SUMMARY 
     The object of the present invention is to provide an easy to use hands-free car kit. Briefly, the hands-free car kit allows a mobile handset to enter and exit privacy mode without the user having to press a privacy button. The simple act of picking up the mobile handset out of its cradle switches the hands-free car kit from hands-free mode to privacy mode. When the mobile handset is installed in the cradle the hands-free car kit enters hands-free mode. If the mobile handset is removed from the cradle the hands-free car kit enters privacy mode. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS AND TABLES 
       For a more complete understanding of the present invention and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is an illustration of a mobile handset installed in the cradle of a hands-free car kit with the magnet in the cradle and the reed switch in the power cord. 
         FIG. 2  is an illustration showing a cut away view of the power cord. 
         FIG. 3  is an illustration showing a cut away view of the cradle. 
         FIG. 4  is an illustration of a mobile handset installed in the cradle of a hands-free car kit with the magnet in the power cord and the reed switch in the cradle. 
         FIG. 5  is an illustration of a mobile handset installed in the cradle of a hands-free car kit with the magnet in the cradle and the reed switch in the mobile hand set. 
         FIG. 6  is an illustration of a mobile handset installed in the cradle of a hands-free car kit with the magnet in the mobile handset and the reed switch in the power cord. 
         FIG. 7  is an illustration of a reed switch. 
       Use of the same reference symbols in different figures indicates similar or identical items. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows one embodiment of the hands-free car kit  10 . The hands-free car kit includes a cradle  15 . The cradle  15  is adapted to hold a mobile handset  13 . A magnet  22  is located in the cradle  15 . A reed switch  25  is located in a power cord  19  for the mobile handset  13 . When the mobile handset  13  is installed in the cradle  15  the magnet  22  is in close proximity to the reed switch  25 . The reed switch  25  has two small metal leaves inside known as reeds. Each leaf is attached at one end and there is a slight separation between the two in the middle. When the reed switch is placed in a magnetic field, the field pulls the two leaves together completing the circuit. When the reed switch is closed, circuitry in the hands-free car kit  10  places the unit in hands-free mode. Conversely, when the switch is open, circuitry in the hands-free car kit  10  places the unit in privacy mode. Such circuitry is well known in the art. In  FIG. 1  the mobile handset  13  lays flat in the cradle  15 , however, it will be clear to one of skill in the art that other mobile handset  13  and cradle  15  configurations are possible. The reed switch  25  will be discussed in further detail with respect to  FIG. 7 .  FIG. 1  shows an embodiment using a reed switch  25 , however it will be clear to a person skilled in the art that any magnetic sensor can be used. A magnetic field sensor is any device that sense a magnetic field, examples include a reed switch or a hall effect sensor. 
     It will be appreciated by one skilled in the art that a reed switch that opens when in a magnetic field can be used. In this embodiment circuitry contained in the hands-free car kit would place the unit in privacy mode when the reed switch is closed and in hands-free mode when the reed switch is open. 
     The orientation of the magnetic field is important. Depending on the relative position of the reed switch and the magnetic field the magnetic field will either open or close the reed switch. Additionally the proximity of the magnetic field is also important. The stronger the magnet is the further away the reed switch can be from the magnet. 
     One skilled in the art will appreciate that the embodiment shown in  FIG. 1  is one example of the present invention. Many different placements are possible. Several different placements are shown in  FIG. 1 , and  FIGS. 3–6 . These embodiments are meant to show several example placements and are not meant to be exhaustive. 
     In another embodiment of the present invention, not shown, the magnet is separate from the hands-free car kit  10 . In this example the magnet can be attached to an area where the hands-free car kit  10  is placed such that when the mobile handset  13  is in the cradle  15  the contacts inside the reed switch  25  are closed. In a similar example a cradle  15  is not used. In this embodiment the reed switch  25  is in the power cord  19 . A separate magnet, not shown in the figure, is placed near the cup holder in a vehicle. When the user places the mobile handset  13  and power cord  19  in the cup holder the separate magnet closes the reed switch  25 . 
     It will be appreciated by one skilled in the art that the figures are for illustrative proposes only. The exact orientation of the magnet  22  and the reed switch  25  will depend on the magnet  22  and reed switch  25  that are chosen. For example, a stronger magnet allows the reed switch to be placed farther away from the magnet. 
     Referring now to  FIG. 2 , a cut away view of the power cord  30  is shown. The power cord is made up of the power cord connector case  35 , the reed switch  38 , the reed switch connections  42 , and the power cord wire  46 . 
     Referring now to  FIG. 3 , the cradle  60  will now be described. The cradle  60  has an outside wall  64  and a cradle mobile handset receiving area  67 . The cradle also contains a magnet. When the mobile handset  13  is placed into the cradle  60  the magnet  22  will cause the reed switch  25  to close. 
     Referring now to  FIG. 4 , another embodiment of the hands-free car kit  90  will be discussed.  FIG. 4  includes a reed switch  98  that is in the cradle  95 , a magnet  100  that is in the power cord  103 , and a mobile handset  92 . Placing the reed switch in the cradle  95  would require the cradle  95  to have some form of connection between the cradle and the hands-free car kit  90  speaker and microphone (not shown). The embodiment shown in  FIG. 4  would be less optimal, because the cradle  95  would be required to have circuitry and wiring adapted to determine the state of the reed switch  98 . In  FIG. 1  the wiring and circuitry for the reed switch can be build into the power cord. The cradle  15  of  FIG. 1  does not require any external connections. It is simply a holder for the mobile handset  13  of  FIG. 1 . 
     Referring now to  FIG. 5 , another embodiment of the hands-free car kit  120  will be discussed.  FIG. 5  includes a reed switch  128  that is in the mobile handset  123 , a magnet  132  that is in the cradle  126 , and a power cord  135 . Placing the reed switch in the mobile handset  123  adds complexity to the mobile handset  123 . 
     While  FIG. 5  shows a possible alternative embodiment of the present invention, the reed switch  128  would be required to be installed in all mobile handsets  123 , even mobile handsets that are never connected to a hands-free car kit. The cost of the reed switch  128  would have to be included in every mobile handset  123  instead of just the car kits that are sold. However in some cases it may be advantageous to place the reed switch  128  in the mobile handset  123  as described below. 
     It will be clear to one skilled in the art that the reed switch  128  can be placed in the handset for use with the separate magnet example above. In one embodiment the reed switch is placed opposite the power cord  135  so that mobile handset  120  can more easily be placed in the cup holder of a vehicle. In this example the end of the mobile handset  120  with the reed switch  128  is placed in a cup holder that has the external magnet attached. The opposite end of the mobile handset  123  can have the power cord  135  attached and the power cord  135  would not interfere with placement of the mobile handset into the cup holder. 
       FIG. 6 , shows an embodiment of the hands-free car kit  150  including a mobile handset  152  with a magnet  158  installed within the mobile handset  152 . The mobile handset has been placed in the cradle  156  and the cradle  156  contains a reed switch  161 . The power cord  165  is connected to the mobile handset  152 . 
     As shown in the embodiment of  FIG. 4 ,  FIG. 6  would be less optimal, because the cradle  156  would be required to have circuitry and wiring adapted to determine the state of the reed switch. In  FIG. 1  the wiring and circuitry for the reed switch can be build into the power cord. The cradle  15  of  FIG. 1  does not require any external connections. It is simply a holder for the mobile handset  13  of  FIG. 1 . Additionally, in the embodiment shown in  FIG. 6 , a magnet  158  would be required in every mobile handset  152 , even mobile handsets that are not used with a hands free car kit. 
     Alternatively the reed switch  161  can be placed in the power cord  165  when the magnet  158  is in the handset  152 . In another embodiment the reed switch  161  can be placed in the mobile handset  152  and the magnet can be placed in the power cord  165 .  FIG. 7  shows a simplified example of a reed switch  200 . The reed switch  200  is made up of a reed switch enclosure  212  that contains a first reed  207  and a second reed  218 . Each reed  207 ,  218  is attached at one end and there is a slight separation between the two in the middle. When the reed switch  200  is placed in a magnetic field, the field pulls the two reeds  207 ,  218  together completing the circuit. The reed switch is connected to external circuitry by a first reed switch lead  215  and a second reed switch lead  220 . It will be clear to one of skill in the art that a reed switch  200  could be devised that would be an open circuit when placed in a magnetic field and a closed circuit when not in a magnetic field. It will also be clear to one of skill in the art that such a reed switch can be used with minor circuitry modifications. 
     One skilled in the art will appreciate that the reed switch  200  can be replaced by a hall effect sensor. The hall effect sensor responds to a magnetic field and produces an analog or digital output proportional to the strength of the magnetic field. The output is used to set the state of the hands-free car kit between hands-free and privacy mode. An advantage of using the hall effect sensor is that hall effect sensors are currently smaller than reed switches. Hall effect sensors however, require more circuitry. 
     The description and drawings show a permanent magnet used to activate the reed switch or hall effect sensor. It will be clear to one skilled in the art that the magnet does not have to be a permanent magnet. The magnet could be an electromagnet. However a permanent magnet has the advantage of not needing to be supplied power as an electromagnet would. 
     The description and drawings contained herein are particular embodiments of the invention and are representative of the subject matter broadly contemplated by the invention. However, the invention encompasses other embodiments that will be apparent to those skilled in the art. Accordingly, the scope of the invention is limited only by the appended claims.

Technology Category: 5