Patent Publication Number: US-6661350-B1

Title: Miniature remote control system

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS &amp; CLAIMS FOR PRIORITY 
     The Applicants hereby claim the benefit of priority for any and all subject matter disclosed in pending U.S. patent application Ser. No. 08/796,853, filed on Feb. 6, 1997 now abandoned, in pending U.S. patent application Ser. No. 08/459,688, filed on Jun. 2, 1995, which is now abandoned; and in U.S. patent application Ser. No. 08/060,455, filed on May 10, 1993, which is now abandoned. 
    
    
     FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not Applicable. 
     FIELD OF THE INVENTION 
     The present invention relates to radio frequency transmitters. More particularly, this invention provides a miniature transmitter that is small enough to fit within a cigarette lighter socket in an auto dashboard. This invention also provides a receiver which, when activated by the transmitter, is able to operate electrical appliances that are connected to the receiver. 
     BACKGROUND OF THE INVENTION 
     Remotely operated garage door openers are a widely used consumer accessory, and are commonly located and activated from a user&#39;s vehicle. These devices provide convenience, security and accessibility for many people who desire or require such a system. Remote operation of garage doors, security gates, lighting and alarms has become a necessity for many people. 
     Existing remote controllers for use in vehicles have had numerous problems associated with their functionality, reliability, security and their location within the vehicle. Common hand-held remote controllers are often bulky and difficult to use. Hand-held units are usually battery operated and commonly malfunction when the stored battery charge is low. Since vehicles are operated in many weather conditions, the available power from battery operated controllers is diminished in cold temperatures. 
     Hand-held units are also easily misplaced, either within the vehicle or by inadvertent removal from the vehicle. Looking for a misplaced remote controller can pose a safety problem in a moving vehicle. Hand-held remote controllers are also prone to damage, as they are commonly used at the same time the user is busy operating a motor vehicle. Previous attempts to provide a convenient means for control of remote systems from the auto dashboard have met with limited results. 
     In U.S. Pat. No. 4,286,262, Wahl discloses a system for opening garage doors in which a radio receiver in the garage, upon receipt of a signal, operates to open the garage door and in which a casing containing a radio transmitter is adapted for insertion into the socket of a cigarette lighter in the driver&#39;s compartment of a motor car. Wahl also discloses a radio transmitting device in which a casing containing a radio transmitter is insertable into a socket of any type at any location together with means for energizing the transmitter to emit a signal when the casing has been inserted in the socket, for whatever purpose the signal may be utilized. 
     In U.S. Pat. No. 3,967,133, Bokern teaches the construction and use of a relatively simple compact and portable device which makes power available at different desired voltages even at remote locations. Bokern also states that his device may include means which obviate the possibility of a polarity reversal or misconnection. 
     In U.S. Pat. No. 5,007,863, Xuan discloses a module-type multi-function power outlet adapter for use of add-on electrical accessories in an automotive vehicle having a cigarette lighter socket. This device embodies a plurality of separate detachable modules which may be attached to a basic module insertable into the lighter socket and constructed to receive the additional modules, so to provide multiple electrical outputs. A simple positioning pin structure ensures correct power leads connection and secures the combination between modules. The resulting solid structure allows easy reception for plug-in accessory equipment. 
     In U.S. Pat. No. 5,073,721, Terrill et al. disclose a noise immune electronic switch which is connectible between a cigarette lighter socket of a vehicle and a plug-in accessory device. 
     In U.S. Pat. No. 4,529,980, Liotine et al. Transmitter and receivers for controlling remote elements which use a synchronous serial transmission format and which allows changes in coding to be automatically made between the receiver and transmitter and wherein the code is stored in memories of the transmitter and receiver and wherein the receiver can generate and transmit a new code with a light emitting diode so as to change the code in the transmitter. The transmitter and the receiver use micro-computers which are suitably programmed and include non-volatile memories. 
     In U.S. Pat. No. 4,409,592, Hunt discloses a packet communication system employing a carrier sense multiple access protocol with detection, with an improved means of collision detection and with an improved means for managing access to a communication medium or channel. 
     In U.S. Pat. No. 4,988,992, Heitschel et al. disclose a system for establishing a code and controlling operation of equipment. The system includes a transceiver including a receiver for the signal generated by the first transmitter and memory for storing the code carried by that signal. The transceiver includes a second transmitter for transmitting a radio frequency signal carrying the code. 
     In U.S. Pat. No. 5,148,159, Clark et al. disclose a remote control system including one or more portable units and base unit which employs identification codes for security. 
     In U.S. Pat. No. 4,665,395, Van Ness discloses an automatic vehicular access control system for use by various government, business and private operations having a need to control the entrance of vehicles to their grounds or facilities. 
     In U.S. Pat. No. 4,912,463, Li discloses a remote control apparatus which has a transmitter which is capable of being switched between a normal position and a changing position, and a receiver which is capable of being switched between a normal mode and a changing mode. 
     In U.S. Pat. No. 4,827,520, Zeinstra discloses a voice actuated control system for controlling vehicle accessories. 
     In U.S. Pat. No. 4,771,399, Snowden et al. disclose a memory programming system which provides a method and apparatus for programming and reading an electronic device memory through its power source connections. 
     In U.S. Pat. No. 3,906,348, Wilmott discloses a serially transmitted code which can be detected by a receiver. 
     In U.S. Pat. No. 4,241,870, Marcus discloses a housing mounted between the visors in the headliner of a vehicle for receiving and supplying operating power to a remote transmitter used for opening garage doors. 
     Previous inventions, such as the device described in U.S. Pat. No. 4,241,870 by Marcus, have located the portable transmitter unit in a overhead location within the motor vehicle, picking up electrical power through a socket located in an overhead console. These units rely on carrier signal technologies, and require line-of-sight operation through the vehicle windshield. Marcus claims that by mounting the transmitter high in a console, the radio waves will exit through the windshield, thus providing the required line of sight operation. Marcus located the controller overhead, in the visor area of an automobile, which has met with minimal acceptance by both automobile manufacturers and consumers. These controller modules are unique to different vehicle models. They impair vision out the front of the vehicle, and cannot be applied to many models, such as convertibles. Special wiring extensions to supply power to these overhead consoles are also required, adding to the manufacturing cost of vehicles supplied with such systems. 
     Hand-held transmitter systems that require a specialized storage area within a vehicle tend to be inappropriate for the interior designs of most vehicle manufacturers. Most hand-held transmitters use carrier signals that require “line of site” operation through the vehicle windshield area. These transmitters use carrier signals with a small number of unique codes. This can pose a security risk when security gates and garage doors are opened inadvertently or deliberately by other transmitters that use the same carrier signal code. 
     U.S. Pat. No. 3,906,348, by Wilmott, provided further encoding and decoding for transmitter and receivers for digital radio control, but the hardware design is inappropriately expensive for integration into a consumer product. 
     Previous remote controllers have been used in motor vehicles to operate garage doors and similar devices. These existing remote controllers are typically large, awkward, and have proven to be difficult to integrate with modern automobile design. While large automobiles, such as Cadillacs™ and Lincolns™, may have enough room over the rear-view mirror, most cars do not have enough space for such large devices. Since most controller designs require line of sight operation, they are susceptible to interference. A significant number of existing remote controller designs fail to offer reasonable security for the user, due to a large number of users and a small number of unique codes. The development of a miniaturized, inexpensive remote controller that can be installed directly in an existing cigarette lighter enclosure, that can provide interference-free operation from a reasonable distance, while providing a large number of unique codes, would constitute a major technological advance. The enhanced performance that could be achieved using such an innovative device would constitute a major technical advance and satisfy a long felt need within the consumer marketplace. 
     SUMMARY OF THE INVENTION 
     The Miniature Remote Control System disclosed and claimed below overcomes the problems encountered by previous mobile remote control systems. The Miniature Remote Control System integrates a radio circuit in a small device that can fit inside a cigarette lighter enclosure in an automobile, truck, van, forklift or other vehicle. When activated, it can be used to open garage doors and security gates, activate or deactivate burglar alarms, turn on lights inside or outside the home, or activate other devices from a remote location. 
     The remote control transmits a coded serial pulse train to a receiver up to 200 feet away. The transmitter board fits inside a cigarette lighter housing and simply plugs into the existing lighter receptacle in a car. A miniature switch located on top of this housing is manually activated to transmit a unique code (one of 19,683) on a 380 MHz carrier frequency. The receiver processes the carrier signal, and extracts the serial code. The code is then compared to the preset code, and, if a match is found, a relay is triggered. 
     The innovative Miniature Remote Control System incorporates the latest remote control technology in a package that is small, safe, reliable, cost-effective, and appropriate for wide acceptance throughout the automotive industry. Installation of the present invention simply entails replacing a standard cigarette lighter with the a remote emitter, which is designed to fit within and operate from a standard lighter receptacle, which is supplied and conveniently located within all modern vehicles. The majority of people who drive vehicles do not smoke, allowing wide market acceptance of the use of the remote emitter located within the standard lighter receptacle. This invention will become the standard-bearer for remote control technology and constitutes a major step forward in the field of automotive accessory design. 
    
    
     An appreciation of other aims and objectives of the present invention and a more complete and comprehensive understanding of this invention may be achieved by studying the following description of a preferred embodiment and by referring to the accompanying drawings. 
     A BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an illustration of the Miniature Remote Control System, using a cutaway view of a garage area of a building. This illustration shows how the present invention would be used to provide remote operation of a standard garage door opener mechanism. 
     FIG. 2 is a perspective assembly view of the remote emitter and a matching lighter receptacle into which the remote emitter would be installed. 
     FIG. 3 is an depiction showing the remote emitter installed within the interior of a vehicle. As the vehicle approaches a garage, the remote emitter is activated to send a carrier signal to open a garage door. 
     FIG. 4 offers a detailed view of a carrier signal being emitted from a vehicle equipped with the remote emitter, as the vehicle approaches the location of the remote receiver. 
     FIG. 5 is an alternative embodiment of the present invention, in which the remote receiver is an integral component of a garage door opener. 
     FIG. 6 is a plan view that illustrates some of the remote control applications for which the Miniature Remote Control System can be used. 
     FIG. 7 is a schematic of the remote emitter. 
     FIG. 8 is a schematic diagram of the remote receiver. 
     FIG. 9 is a schematic of the receiver power supply. 
     FIG. 10 is a depiction of the receiver board layout for the present invention. 
     FIG. 11 shows an embodiment of the second receiver board layout. 
     FIG. 12 shows a top view of a board design for a production transmitter. 
     FIG. 13 shows a side view of the production transmitter board. 
     FIG. 14 illustrates details the component side of the bare production transmitter board. 
     FIG. 15 provides a detailed view of the circuit side of the bare production design transmitter board. 
     FIG. 16 is a composite view of the production transmitter board. 
     FIG. 17 is a top view of the surface mount transmitter board embodiment. 
     FIG. 18 is a detailed plan view of the surface mount remote emitter assembly. 
     FIG. 19 is a detailed side view of the surface mount remote emitter assembly. 
     FIG. 20 provides a plan view of an alternate transmitter embodiment. 
     FIG. 21 is a side view of the alternate transmitter embodiment. 
     FIG. 22 shows the remote emitter designed to fit in the cigarette lighter receptacle of a Lincoln™ automobile. 
     FIG. 23 shows the remote emitter designed to be used in the cigarette lighter receptacle of a Mercedes Benz™. 
     FIG. 24 is an expanded view of an alternate embodiment of an extended remote emitter. 
     FIG. 25 shows an installed view of the extended remote emitter. 
     FIG. 26 reveals a block diagram of another alternate embodiment of the present invention, the Miniature Transceiver Control System. 
     FIG. 27 is a perspective illustration of the remote transceiver, as it would be installed in the console of a vehicle. 
     FIG. 28 is a block diagram of the power circuitry for the remote transceiver. 
    
    
     DETAILED DESCRIPTION OF PREFERRED &amp; ALTERNATIVE EMBODIMENTS 
     System Overview 
     FIG. 1 is an illustration of the Miniature Remote Control System  10 , which shows a cutaway view of a garage area G. The Miniature Remote Control System  10  provides a miniature, radio frequency remote emitter  12  that is designed be installed within a vehicle V. The remote emitter  12  is used to operate an external device ED, such as a garage door opener GDO, that is connected to a remote receiver  14 . When activated, the remote emitter  12  transmits a 380 MHz coded serial pulse train  16 . At this frequency, the coded serial pulse train  16  can easily penetrate obstructions located between the remote emitter  12  and the remote receiver  14 , such as the vehicle V, the vehicle windshield W, the garage wall GW, and the garage door GD. In the claims, the term “carrier signal” encompasses any coded serial pulse trains  16  described in the specification. 
     The remote emitter  12  is able to transmit the serial pulse train  16  to the remote receiver  14  from a distance up to 200 feet away. When in range, the remote receiver  14  senses the incoming serial pulse train  16  through the receiver antenna  18 . The remote receiver  14  processes the coded signal pulse train  16 , and extracts the serial transmitter code  20 . The transmitter code  20  is then compared to the preset receiver code  22 . If the transmitter code  20  and the receiver code  22  are identical, the remote receiver  14  provides the logic necessary to provide power to operate an external device ED, such as the garage door opener GDO. 
     The remote receiver  14  is powered by a 16 volt direct current power converter  24  which is attached to an existing alternating current power source (VAC). In this embodiment, the garage door opener GDO can also be activated by overriding the remote receiver  14  by using a manual button MNL. 
     FIG. 2 shows a perspective view  26  of the remote emitter  12  and portrays how the remote emitter  12  would be installed in a cigarette lighter receptacle  28  which is located in a vehicle V. The lighter receptacle  28  is supplied with a direct voltage source BAT from the vehicle V, with a positive polarity connection  30  and a negative polarity connection  32 . 
     The emitter body  34  of the remote emitter  12  is an exterior housing that encloses the internal components of the remote emitter  12 . An emitter retainer  36  is used to correctly locate the remote emitter  12  within the lighter receptacle  28 . The emitter retainer  36  also acts as an electrical conducting channel between the remote emitter  12  and the negative polarity connection  32 . A switch  37  is located on top of the emitter body  34 , which is manually activated by the user to power the remote emitter  12  and send a serial coded pulse train  16 . 
     A view of the installed controller  38  is shown in FIG.  3 . The remote emitter  12  is installed in a lighter receptacle  28  which is located inside a vehicle V. The lighter receptacle  28  is located in different locations within the vehicles V of various manufacturers, but is usually located on the dashboard D or a console C, as indicated by FIG.  3 . The location of the lighter receptacle  28  is designed by vehicle manufacturers to be conveniently accessed by the driver or passenger while they are seated in seats S. 
     FIG. 3 also portrays how the remote emitter  12  would be used to transmit a coded signal pulse train  16  towards a garage G and a garage door GD. As a driver located in vehicle V approaches a garage G, the driver can easily reach and activate the remote emitter  12  by simply pushing down the switch  37  on top of the emitter body  34 . Upon activation, the remote emitter  12  emits the coded serial pulse train  16 , which includes a unique transmitter code  20  (one of 19,683) on a 380 MHz carrier frequency. 
     FIG. 4 shows a detailed illustration  40  of an approaching vehicle V as it arrives at a residential building B and a garage G. The coded serial pulse train  16  is transmitted from a remote emitter  12  located in the vehicle V. In this application, the pulse train  16  is used to activate a remote receiver  14  that can provide the logic necessary to open or close a garage door GD. 
     FIG. 5 is a depiction  42  of an alternative embodiment of the present invention in which the remote receiver  14  is contained within an integrated garage door opener  44 . 
     FIG. 6 is a plan view  46  of some of the many useful applications for which the Miniature Remote Control System  10  may be used. Upon arriving at or departing from a building B, a user in vehicle V can activate the remote emitter  12  to send a coded serial pulse train  16  to a security gate receiver  48  in order to open or close a security gate SG. Exterior lighting EL can be controlled in a similar manner using an exterior light receiver  50 . Sprinklers LC can be activated or shut off using a landscape control receiver  52 , thus allowing the vehicle passengers to exit the vehicle V without getting wet. The remote emitter  12  may also be used to arm or to disarm a home alarm and security system SA by using a security system receiver  54 . Other devices inside the building B may activated, by using a remote emitter  12  to activate an interior lighting receiver  56  to turn lights IL off or on around the house B, or by activating a climate control receiver  58  to operate heating and air conditioning systems AC. 
     A schematic diagram of the transmitter circuitry  60  within the remote emitter  12  is revealed in FIG.  7 . To activate the remote emitter  12 , the user simply pushes down the switch  37  on the emitter body  34 , which allows the transmitter circuitry  60  to be energized with the 13.7 volt DC power supplied by the positive polarity connection  30  and the negative polarity connection  32  in the vehicle V. 
     The transmitter circuitry  60  incorporates three primary systems, including the emitter power supply  62 , the emitter encoder  64 , and the emitter oscillator  66 . The emitter power supply  62  provides filtered direct voltage power to the emitter encoder  64  and the emitter oscillator  66 . The emitter encoder  64  uses an encoding chip  68 , which in this embodiment is an MC 145026, manufactured by Motorola. Nine trinary code input traces  70  are supplied into the encoding chip  68 . When the transmitter circuitry  60  is manufactured, the input traces  70  are selectively cut to produce high, low, or open states. In this manner, each remote emitter  12  produced can have one of 19,683 unique transmitter codes  20 , derived from  3   9  possible configurations. 
     A timing network  72  is also provided within the emitter encoder  64 . The timing network  72  consists of an RTC timing resistor  74 , a CTC timing capacitor  76 , and a source resistor  78 . The source resistor  78  is used as a buffer for the timing network  72 . The clock frequency of the encoder  64  is determined by the selection of values for the RTC timing resistor  74  and the CTC timing capacitor  76 . This frequency is determined by the following relationship: 
     
       
         Clock Frequency (cycles/sec)=1/(2.3 *CTC*RTC ). 
       
     
     To obtain more unique transmitter codes  20  for the remote emitter  12  than the 19,683 possible combinations offered by the encoding chip  68  alone, values of the RTC timing resistor  74  and the CTC timing capacitor  76  can be changed. 
     When activated, the emitter oscillator  66  produces the encoded serial pulse train  16 . A 1.0 uH 5% emitter inductor  80  acts as a filter in the transmitter circuitry  60  to isolate the 380 MHz signal produced by the emitter oscillator  66  from the clean voltage necessary for operation of the encoding chip  68 . A signal resistor  82  is located between the emitter encoder  64  and the emitter oscillator  66 . The value chosen for the signal resistor  82  determines the transmission power of the remote emitter  12 . In the preferred embodiment, a 33K signal resistor  82  is used to provide interference free operation between the remote emitter  12  and a remote receiver  14  up to 200 feet away. Appropriate values for the signal resistor  82  are also limited by the maximum allowable transmission power dictated by the Federal Communications Commission (FCC). 
     A coupling transformer  81  is used to isolate the transmitter circuitry  60  from the emitter antenna  83 . This creates a better impedance match between the transmitter circuitry  60  and the emitter antenna  83 . In one embodiment of the invention, a circuit trace  122  on the bare production transmitter board  118  may be employed as an antenna for the remote emitter  12 . In another embodiment of the present invention, the emitter switch  37  is linked to the emitter oscillator  66 . When the switch  37  is depressed by the user, the user becomes the emitter&#39;s antenna, and provides an unobstructed line of sight for the coded serial pulse train  16  through the vehicle windshield WS. 
     FIG. 8 is a schematic diagram of the receiver circuitry  84  used with the remote receiver  14 . The incoming 380 MHz serial pulse train signal  16  arrives at the receiver antenna  18 , and is then processed by an rf super-regenerative receiver  86 . The super-regenerative receiver  86  operates with an extremely wide bandwidth, which allows the Miniature Remote Control System  10  to operate over a very large temperature range. Since the ambient temperature of the remote emitter  12  in a vehicle V or the remote receiver  14  in a building B can commonly be anywhere from 15 degrees F to 130 degrees F, the 380 MHz coded serial pulse train  16  can have a tolerance of as much as +/−5 MHz. 
     A high frequency filtering circuit  88  is coupled to the super-regenerative receiver  86 . Two 0.001F high frequency filter capacitors  90  are coupled to a filter transistor  92 . The high frequency filter capacitors  90  act as a buffer between the super-regenerative receiver  86  and the receiver amplifier  94  and data separator  98  circuits. 
     A data amplifier  94  is then used to begin to amplify the encoded serial pulse train  16 . An operational amplifier  96  is used to amplify the 10 KHz serial pulse train  16  by a factor of 10. The operational amplifier  96  has a low frequency bandwidth of only 1-4 MHz, and acts to further filter any residual high frequency components. 
     A data separator  98  is coupled to the receiver amplifier  94 . The data separator  98  adjusts itself to the output signal of the first operational amplifier  96 , to allow for signal shift due to temperature variations in the remote emitter  12 . The data separator  98  uses a second operational amplifier  100  to compare the actual serial pulse train  16  to the averaged dc level of the serial pulse train  16 . A slight amount of hysteresis is added through a 1.5 Meg-ohm resistor  101 . This provides clean switching and enhanced noise rejection. The output of the data separator  98  is a faithful reproduction of the serial pulse train  16  output from the emitter encoder  64 . 
     The remaining serial pulse train  16  is output from the data separator  98  to a receiver decoder  102 , which in this embodiment is an MC 145028, manufactured by Motorola. The receiver decoder  102  is preset when manufactured with a trinary receiver code  22  to match the transmitter code  20  from the encoding chip  68  in the remote emitter  12 . The receiver decoder  102  compares the transmitter code  20  to the receiver code  22 . If the two codes  20  &amp;  22  are identical for two sequential serial pulse trains  16  received from the remote emitter  12 , the receiver decoder  102  supplies the necessary logic to trigger a relay  104  that will activate the  16  volt DC signal  106  necessary to implement the exterior device ED, such as a garage door opener GDO. 
     FIG. 9 is a schematic of the receiver power supply  108  which is used to supply the regulated 12 volt DC power necessary for proper function of the receiver circuitry  84  as well as the 16 volt DC power  106  necessary to power the relay  104 . 
     FIG. 10 shows the first receiver circuit board  110  used in the 380 MHz remote receiver circuitry  84 , which includes the super-regenerative receiver  86 , the receiver amplifier  94 , and the data separator  98 . FIG. 11 reveals a second receiver circuit board  112  that is used in conjunction with the first receiver circuit board  110  to complete the receiver circuitry  84  within the remote receiver  14 . The second receiver circuit board  112  includes the receiver decoder  102  and the receiver power supply  108 . 
     For the remote emitter  12  to fit within in a small area such as a lighter receptacle  28  within a vehicle V, the transmitter circuitry  60  must be able to be packaged within an extremely small volume. FIGS. 12 through 16 illustrate different views of the components that make up the transmitter circuitry  60  within the remote emitter  12 . FIG. 12 shows a top view the stacked production transmitter board  114  that achieves all the functionality required of the transmitter circuitry  60  in a micro-miniature design that can fit within the emitter body  34  of the remote emitter  12 . FIG. 13 reveals a side view  116  of the production transmitter board  114 , whose components and layout have been advantageously chosen to minimize the exterior dimensions of the transmitter circuit board  114 . 
     FIG. 14 illustrates details the component side of the bare production transmitter board  118 , from which components are assembled to make up the completed production transmitter board  114 . The bare transmitter board  118  is designed to preserve the compact nature of the completed transmitter board  114 , while minimizing trace path lengths, and providing adequate room for assembly, quality control, and heat rejection. 
     FIG. 15 provides a detailed view  120  of the circuit side of the bare transmitter board  118 . All board traces  122  on the bare transmitter board  118  are designed to be as short as possible to minimize circuit response time and heat loss, while still providing adequate distance between traces  122  to avoid malfunctions. 
     FIG. 16 provides a composite view  124  of the production transmitter board  114 . This view exemplifies how the components that make up the board  114  have been arranged to advantageously provide an extremely small volume while still allowing adequate room for manufacture, heat rejection, and testing. 
     FIG. 17 is a top view of a preferred surface-mounted transmitter embodiment  126 . The surface-mount transmitter  126  provides all the functionality required for the remote emitter  12 , while advantageously employing surface-mounted component assembly design. As the remote emitter  12  can be used for numerous applications, the cost to manufacture the components must be considered to provide as large an installed customer base as possible. Modern automated manufacturing methods and the availability of high quality “surface-mount” electronic components at a reasonable cost has made the surface-mount transmitter  126  desirable to achieve the lowest possible cost of the present invention for the user. 
     FIG. 18 reveals a detailed plan view  128  of the remote emitter  12 . The surface-mount transmitter board  126  is installed inside the emitter body  34 . To provide the mechanical connection to locate the remote emitter  12  within the lighter receptacle  28 , and to provide the proper electrical pathway between the remote emitter  12  and the negative polarity connection  32 , an emitter retainer  36  is provided. The emitter retainer  36  is attached to the emitter body  34  with a spring  130  and a snap ring  132 . The spring  130  and snap ring  132  act to provide the user of the remote emitter  12  with a tactile feel when the button  37  is pushed, similar to the spring loaded “snap” of a calculator keypad button that provides a user with a tactile response. 
     FIG. 19 provides a detailed side view  134  of the embodiment of the remote emitter  12  shown in FIG.  18 . This view illustrates how the necessary electronic components that make up the surface mount transmitter  126  are placed to fit within the confines of the emitter body  34  with generous tolerances, allowing the use of multiple parts sourcing for non-interrupted, large-volume manufacture of the remote emitter  12 . 
     FIG. 20 provides an enlarged cut-away plan view of an alternate transmitter embodiment  136  of the remote emitter  12 . From this view it can be seen how the surface-mount transmitter circuit board  126  that provides all the required functionality of the remote emitter  12  can be conveniently packaged within the exterior body  34  that can be installed in a common lighter receptacle  28 . 
     FIG. 21 is an enlarged sectional side view  138  of the alternate transmitter embodiment  136  shown in FIG.  20 . In this view the transmitter conductive pathway  140  is shown. The conductive pathway  140  makes contact with the positive polarity connection  30  in the vehicle V when the user pushes the button  37  to activate the remote emitter  12 . This powers the remote emitter  12  to send a coded serial pulse train  16  to the remote receiver  14  for remote control of an external device ED, such as a garage door opener GDO. 
     The lighter receptacles  28  and the interior design requirements of vehicles V produced by various manufacturers require that the remote emitter  12  be packaged with slightly different geometries and styling. The production transmitter board  114  is designed to be located within all appropriate emitter bodies  34  which are designed to fit within the standard lighter receptacles  28  of vehicles V produced by substantially all manufacturers. FIG. 22 shows a side view of a remote emitter  141  designed to fit in a Lincoln™ automobile. FIG. 23 reveals a side view of a remote emitter  142  designed to be used in a Mercedes Benz™. 
     FIGS. 24 and 25 are detailed expanded and installed assembly views of an alternate embodiment of the extended remote emitter  144 . This configuration allows expanded functionality and versatility that is advantageous for many users. The extended remote emitter  144  allows the user to control multiple devices ED remotely from a vehicle V, by providing the circuitry and controls to send a number of unique coded serial pulse trains  16  to different external devices ED, such as a garage door opener GDO, a security system receiver  54 , a lighting control receiver  56 , and a security gate receiver  48 . The multiple button keypad  146  shown in FIG. 24 has single buttons  148  devoted to single transmitting functions. Other embodiments that require increased security or the use of a small number of buttons  148  to control a large number of external devices ED may use a keyed combination of required button strokes to provide the correct coded serial pulse train  16  to operate external devices ED. 
     The location of the multiple button keypad  146  for this embodiment is placed to be easily seen and operated by the user within the vehicle V. To enhance the ease with which the extended remote emitter  144  is used, the single buttons  148  can be color keyed, illuminated, or supplied with names or icons to identify the functions for which they are to be used. 
     Another feature of the extended remote emitter  144  is the extension receptacle  150  that is shown in FIG.  24 . Many modern vehicles V are equipped with optional accessories ACC such as portable cellular phones CP, which often use the lighter receptacle  28  within a vehicle V to supply DC power. The extension receptacle  150  provided by the extended remote emitter  144  allows the attachment of additional accessories ACC, such as cellular phones CP. As the extended remote emitter  144  is designed to draw a very small amount of power from the vehicle DC power source BAT, the use of both the extended emitter  144  and a cellular phone CP within the lighter receptacle  28  is within the amperage limits of vehicle electrical circuit BAT, which is designed to power a cigarette lighter CL. 
     FIG. 26 reveals a block diagram of another alternate embodiment of the present invention, the Miniature Transceiver Control System  152 , which comprises a remote transceiver  154  in a vehicle V, and a secondary transceiver  156  attached to external devices ED. The Miniature Transceiver Control System  152  provides both remote control of external devices ED from a vehicle V, and communication back to the remote transceiver  154  from the secondary transceiver  156 . 
     The Miniature Remote Transceiver System  152  is able to transmit and receive information on a carrier frequency of 902 to 928 MHz. The Federal Communications Communication (FCC) allows a high maximum transmission power for systems operating in the 900 MHz bandwidth. Operation of the Miniature Transceiver Control System  152  in this 900 MHz frequency band allows the system to operate with a range exceeding two miles, while advantageously providing interference free operation from obstacles, such as the vehicle body VB, buildings B, and garage walls GW. 
     A user in a vehicle V can activate the remote transceiver  154  to send a coded serial pulse train  16  by simply pressing down on buttons  148  located on the transceiver keypad  160 . Activation of a desired coded serial pulse train  16  may be accomplished with a stroke of an individual button  148 , or may be accomplished with a more elaborate predetermined combination of multiple buttons  148 . The transceiver keypad  160  is coupled in series to a transceiver microprocessor  162 , a transceiver transmitter  164 , and a transceiver antenna  166 . When the user supplies the correct transmitter code  20  to the transceiver microprocessor  162 , the transceiver microprocessor  162  activates the transceiver transmitter  164  to send the appropriate coded serial pulse train  16  containing the transmitter code  20 . The coded serial pulse train  16  provided by the transceiver transmitter  164  is broadcast from the vehicle V, through the transceiver antenna  166 , toward the secondary transceiver  156 . 
     The secondary transceiver  156  is typically located in a building B, and is powered by a standard 120 volt alternating current source VAC. The secondary transceiver  156  has inputs for connection to external devices ED, such as security and alarm systems SA, fire detectors FD, garage door openers GDO, and heating and air conditioning systems AC. 
     The secondary transceiver  156  is able to receive, amplify, and decode the coded serial pulse train  16  sent by the remote transceiver  154 , and is able to activate external devices ED, such as security and alarm systems SA and garage door openers GDO. The secondary transceiver  156  is also able to transmit an information pulse train  158  back to the remote transceiver  154 . 
     The remote transceiver  154  is able to receive the information pulse train  158  from the secondary transceiver  156 . The information pulse train  158  may contain information for use by the transceiver microprocessor  162 , such as new transmitter codes  20  required to provide remote control for external devices ED. The information pulse train  158  may also contain information to be communicated to the user, such as the status of external devices ED, or confirmation of commands sent to the secondary transceiver  156  by the remote transceiver  154 . Information regarding the status of external devices ED that can be transmitted to the user may be of great value to the user in a vehicle V. Criminal activity that activates a security and alarm system SA which is connected to a secondary transceiver  156  in a building B can be communicated to a user in a vehicle V. A fire within a building B that activates a fire detector FD which is connected to a secondary transceiver  156  can be communicated to a user. 
     The information pulse train  158  sent by the secondary transceiver  156  enters the remote transceiver  154  through the transceiver antenna  166 . The transceiver antenna  166  is coupled in series to the transceiver receiver  168 , the transceiver microprocessor  162 , and a backlit liquid crystal display  170 . The transceiver microprocessor  162  is also coupled to function LEDs  172 . When an information pulse train  158  arrives at the transceiver antenna  166 , it is processed by the transceiver receiver  168  and sent to the transceiver microprocessor  162 . If the information pulse train  158  contains information for use only by the transceiver microprocessor  162 , such as a new transmission code  20 , the transceiver microprocessor  162  stores the new transmission code  20  in its memory. If the information pulse train  158  contains information to be communicated with the user in the vehicle V, the transceiver microprocessor  162  sends the information to the liquid crystal display  170  or to the function LEDs  172 , where the information is provided to the user. 
     FIG. 27 is a perspective illustration  174  of the remote transceiver  154 , as it would be installed in the console C of a vehicle V. In this embodiment, the remote transceiver  154  is designed to fit within a standard ash tray AT in a vehicle V. A power pickup  176  is provided on the remote transceiver  154  to supply power to the remote transceiver  154  from the vehicle DC power source BAT. The power pickup  176  is designed to fit within a standard cigarette lighter receptacle  28 . The transceiver keypad  160  is conveniently located on the upper surface of the remote transceiver  154 . A backlit liquid crystal display  170  and a function LED  172  are also provided on the upper surface of the remote transceiver  154 , to provide communication to the user from the secondary transceiver  156  in the house B. An extension receptacle  150  is also provided on the remote transceiver  154  to provide a means for attachment of additional accessories ACC, such as cellular phones CP. To install the remote transceiver  154 , the cigarette lighter CL and ash tray AT can simply be removed and replaced with the remote transceiver  154 . 
     FIG. 28 is a block diagram of the power circuitry  178  for the remote transceiver  154 . Power is supplied to the remote transceiver  154  from the vehicle DC power source BAT through the power pickup  176 . A transceiver power supply  180  is located within the remote transceiver  154 , and is coupled to the power pickup  176 . The transceiver power supply  180  conditions the DC power source BAT to provide appropriate power outputs  182  for components in the remote transceiver  156  and for secondary accessories ACC that are coupled to the extension receptacle  150 . 
     Alternate Antenna Configurations 
     The operating frequency and radiated power of the present invention is regulated by the FCC. This device must operate within the constraints of those regulations. Under Section 15.231, periodic operation in the band 40.66-40.70 MHz and above 70 MHz of remote control devices such as garage door openers are allowed. Since the allowable radiated field strength is low (&lt;12,500 μV/meter average value measured at 3 meters for frequencies above 470 MHz), the method of coupling the RF energy into the antenna can be primarily driven by economics as opposed to power efficiency. Most importantly, the RF energy must exit the car, usually through a multipath composing of several reflections, and enter the house or a garage where a receiver intercepts the signal and operates the garage door or other device. 
     Modulation &amp; Message Coding 
     The basic system operates at 900 MHz when the operator presses the button labeled “Close Switch.” At the time of switch closure, the transmitter begins sending a coded message to the receiver. Once activated by the switch, the transmitter automatically ceases transmission within five seconds after the switch is released. There are two key features of the coded message. First, a unique code is repeatedly transmitted. The receiver is designed to look for codes that have been identified as valid for executing the desired remote function such as opening the garage door. The receiver must receive the same correct code three times before it allows the remote operation. The fact that three correct codes must be received is based upon current technology. The intent is to avoid susceptibility to random noise. In fact, more than three makes for a more robust system. The only problem with increased required occurrences is the length of time the operator must wait before the remote device begins to respond. The present invention is designed to make the reaction appear to be instantaneous from a user&#39;s point of view. To take advantage of power averaging, the code will be repeated at a rate of twenty times per second on average. Secondly, the transmitter uses an “ALOHA” messaging scheme. ALOHA is a messaging technique that allows multiple users to operate simultaneously on the same frequency. 
     When dealing with shared channels (a channel being an assigned frequency band), one must be prepared to resolve conflicts that arise when more than one demand is placed on the channel. For example, in the case of multiple garage door devices within close proximity, whenever a portion of the transmission of one user overlaps with the transmission of another user, then the two collide and “destroy” each other, unless a random access technique such as ALOHA is utilized. 
     Pure ALOHA permits a user to transmit any time it desires. If a user transmits a code word, and within some appropriate time-out period following its transmission it receives an acknowledgment from the destination, then it knows that no conflict occurred. Otherwise, it assumes that a collision occurred and it must retransmit. To avoid continuously repeated conflicts, The retransmission delay is randomized across the transmitting devices, thus spreading the retry packets over time. This approach works most effectively with a transceiver on both ends. However, that basic ALOHA approach still works using the operator as the feedback for acknowledging the garage door has opened or closed. A basic system using ALOHA, the transmitter sends a coded message upon switch closure and then waits a period of time before retransmitting the message. This process is repeated until the operator releases the switch. The delay between messages is a random period of time. The time between messages is long with respect to the time it takes to transmit a message. The transmitter codes the RF using pulse modulation. Therefore, the transmitter does not emit RF energy while waiting to send the message. 
     Basic Receiver 
     The receiver is operational at all times waiting for the correct message to be decoded by the RF receiver. After the receiver get three valid messages, the remote operation is performed such as opening a garage door. This is one of three basic modes of operation. The second mode of operation is the entry of new valid codes. This is achieved by holding down the programming button “switch” and operating the new transmitter. The receiver reads in the coded message and saves the code word in the non volatile random access memory NOVRAM. The new transmitter is now capable of operating the remote system. The third mode of operation is clearing or resetting of all stored codes in the NOVRAM of the receiver. This is done by turning power on while the programming button is pressed. Upon boot-up the microcontroller recognizes the depressed programming button and then erases the contents of the NOVRAM. 
     Manufacturing 
     For low cost manufacturing purposes, all receivers are initially configured during the manufacturing process with the same code. This is accomplished within the software design. This allows for simple testing of the receiver as it is being built. 
     The transmitter randomly selects a code word on initial power up. This gives the transmitter a unique code word that is stored in NOVRAM. The random selection of the code word is done partly with the hardware timer that is built into the microcontroller and through a software timer. Upon the initial power-on and boot-up process the microcontroller checks to verify that a valid code word has been stored in the NOVRAM. If there is no code word the microcontroller starts the hardware and software timers. The operator, some random time later, will push the button marked “Close the switch.” This stops the counters and the microcontroller loads the contents of the counters into the NOVRAM as the valid code word. The operator is most likely to be a technician during the testing phase of the manufacturing process. The microcontroller is capable of counting very fast. The hardware and software counters count from zero to maximum count more than twenty times a second. After maximum count the counters automatically start over at zero. The operator pressing the button randomizes the process. This random number algorithm can produce over a billion unique code words. 
     This method allows the transmitters and receivers to be built and tested independently. Transmitters and receivers are not matched pairs, nor do they require the setting of DIP (dual in-line package) switches. Replacement transmitters can be purchased and programmed into the receiver. 
     The invention also provides several alternative methods of programming the transmitter with unique codes. An additional connector could be used to down load information. However, this concept is inferior due to the cost and physical location constraints of the application. Instead, a technique has been developed that allows the information to be encoded on the power supply leads. Therefore, the unique codes can be downloaded without adding additional cost or complexity to the transmitter circuit. This is an important concept for making transmitters compatible with or vendors receivers. Current state of the art devices change codes by selecting settings on a DIP switch, on both the transmitter and receiver. With this embodiment, the user can program the transmitter with a compatible code and then set the dip switches on the receiver to match the transmitter. It is envisioned that a distributor will sell transmitters independent of the receiver for replacement of lost or broken transmitters. The distributor would concurrently provide a service of allowing the user to select a code to be programmed into the transmitter NOVRAM. This is accomplished with a special box that the user can plug the transmitter into and activate the programmer. The process only takes a few seconds and allows the user to either pick a code or allow the box to randomly select a code and then print out the code word so that the dip switches can be properly set on the receiver. 
     CONCLUSION 
     Although the present invention has been described in detail with reference to particular preferred and alternative embodiments, persons possessing ordinary skill in the art to which this invention pertains will appreciate that various modifications and enhancements may be made without departing from the spirit and scope of the Claims that follow. The imaging equipment that has been disclosed above is presented to educate the reader about particular embodiments, and is not intended to constrain the limits of the invention or the scope of the Claims. The List of Reference Characters which follows is intended to provide the reader with a convenient means of identifying elements of the invention in the Specification and Drawings. This list is not intended to delineate or narrow the scope of the Claims. 
     
       
         
           
               
             
               
                   
               
               
                 LIST OF REFERENCE CHARACTERS 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                   
                  10 
                 Miniature Remote Control System 
               
               
                   
                  12 
                 Remote emitter 
               
               
                   
                  14 
                 Remote receiver 
               
               
                   
                  16 
                 Coded serial pulse train 
               
               
                   
                  18 
                 Receiver antenna 
               
               
                   
                  20 
                 Transmitter code 
               
               
                   
                  22 
                 Receiver code 
               
               
                   
                  24 
                 Receiver power converter 
               
               
                   
                  26 
                 Perspective view of remote emitter 
               
               
                   
                  28 
                 Cigarette lighter receptacle 
               
               
                   
                  30 
                 Positive polarity connection 
               
               
                   
                  32 
                 Negative polarity connection 
               
               
                   
                  34 
                 Emitter body 
               
               
                   
                  36 
                 Emitter retainer 
               
               
                   
                  37 
                 Switch 
               
               
                   
                  38 
                 Installed Controller 
               
               
                   
                  40 
                 Illustration of approaching vehicle 
               
               
                   
                  42 
                 Depiction of integrated garage door opener 
               
               
                   
                  44 
                 Integrated garage door opener 
               
               
                   
                  46 
                 Plan view of applications 
               
               
                   
                  48 
                 Security gate receiver 
               
               
                   
                  50 
                 Exterior light receiver 
               
               
                   
                  52 
                 Landscape control receiver 
               
               
                   
                  54 
                 Security system receiver 
               
               
                   
                  56 
                 Interior lighting receiver 
               
               
                   
                  58 
                 Climate control receiver 
               
               
                   
                  60 
                 Transmitter circuitry 
               
               
                   
                  62 
                 Emitter power supply 
               
               
                   
                  64 
                 Emitter encoder 
               
               
                   
                  66 
                 Emitter oscillator 
               
               
                   
                  68 
                 Encoding chip 
               
               
                   
                  70 
                 Trinary code input traces 
               
               
                   
                  72 
                 Timing network 
               
               
                   
                  74 
                 RTC timing resistor 
               
               
                   
                  76 
                 CTC timing capacitor 
               
               
                   
                  78 
                 Source resistor 
               
               
                   
                  80 
                 Emitter inductor 
               
               
                   
                  81 
                 Coupling transformer 
               
               
                   
                  82 
                 Signal resistor 
               
               
                   
                  83 
                 Emitter antenna 
               
               
                   
                  84 
                 Remote receiver circuitry 
               
               
                   
                  86 
                 Super-regenerative receiver 
               
               
                   
                  88 
                 High frequency filtering circuit 
               
               
                   
                  90 
                 High frequency filter capacitor 
               
               
                   
                  92 
                 Filter transistor 
               
               
                   
                  94 
                 Data amplifier 
               
               
                   
                  96 
                 First operational amplifier 
               
               
                   
                  98 
                 Data separator 
               
               
                   
                 100 
                 Second operational amplifier 
               
               
                   
                 102 
                 Receiver decoder 
               
               
                   
                 104 
                 Relay 
               
               
                   
                 106 
                 16 volt DC signal 
               
               
                   
                 108 
                 Receiver power supply 
               
               
                   
                 110 
                 First receiver board 
               
               
                   
                 112 
                 Second receiver board 
               
               
                   
                 114 
                 Production transmitter board 
               
               
                   
                 116 
                 Side view of production transmitter board 
               
               
                   
                 118 
                 Bare transmitter board 
               
               
                   
                 120 
                 Circuit side of bare production board 
               
               
                   
                 122 
                 Board traces 
               
               
                   
                 124 
                 Composite view of production transmitter board 
               
               
                   
                 126 
                 Surface mounted transmitterboard 
               
               
                   
                 128 
                 Plan view of remote emitter 
               
               
                   
                 130 
                 Spring 
               
               
                   
                 132 
                 Snap ring 
               
               
                   
                 134 
                 Detailed side view of remote emitter 
               
               
                   
                 136 
                 Alternate transmitter embodiment 
               
               
                   
                 138 
                 Sectional side view of alternate transmitter embodiment 
               
               
                   
                 140 
                 Conductive pathway 
               
               
                   
                 141 
                 Remote emitter to fit in Lincoln ™ automobile 
               
               
                   
                 142 
                 Remote emitter to fit in Mercedes Benz ™ automobile 
               
               
                   
                 144 
                 Extended remote emitter 
               
               
                   
                 146 
                 Multiple button keypad 
               
               
                   
                 148 
                 Single button 
               
               
                   
                 150 
                 Extension receptacle 
               
               
                   
                 152 
                 Miniature Transceiver Control System 
               
               
                   
                 154 
                 Remote transceiver 
               
               
                   
                 156 
                 Secondary transceiver 
               
               
                   
                 158 
                 Information pulse train 
               
               
                   
                 160 
                 Transceiver keypad 
               
               
                   
                 162 
                 Transceiver microprocessor 
               
               
                   
                 164 
                 Transceiver transmitter 
               
               
                   
                 166 
                 Transceiver antenna 
               
               
                   
                 168 
                 Transceiver receiver 
               
               
                   
                 170 
                 Liquid crystal display 
               
               
                   
                 172 
                 Function LEDs 
               
               
                   
                 174 
                 Perspective illustration of remote transceiver 
               
               
                   
                 176 
                 Power pickup 
               
               
                   
                 178 
                 Remote transceiver power circuitry 
               
               
                   
                 180 
                 Transceiver power supply 
               
               
                   
                 182 
                 Power outputs 
               
               
                   
                 AC 
                 Heating and air conditioning system 
               
               
                   
                 ACC 
                 Secondary accessories 
               
               
                   
                 ANT 
                 Antenna 
               
               
                   
                 AT 
                 Standard ashtray 
               
               
                   
                 B 
                 Building 
               
               
                   
                 BAT 
                 Vehicle DC power source 
               
               
                   
                 BT 
                 Button 
               
               
                   
                 C 
                 Console 
               
               
                   
                 CA 
                 Cap 
               
               
                   
                 CL 
                 Cigarette lighter 
               
               
                   
                 CP 
                 Cellular phone 
               
               
                   
                 D 
                 Dashboard 
               
               
                   
                 ED 
                 External device 
               
               
                   
                 EL 
                 Exterior lighting 
               
               
                   
                 FD 
                 Fire detector 
               
               
                   
                 G 
                 Garage 
               
               
                   
                 GD 
                 Garage door 
               
               
                   
                 GDO 
                 Garage door opener 
               
               
                   
                 G 
                 Garage wall 
               
               
                   
                 GR 
                 Ground ring 
               
               
                   
                 IL 
                 Indoor lighting 
               
               
                   
                 LC 
                 Sprinklers 
               
               
                   
                 M 
                 Mold 
               
               
                   
                 MNL 
                 Manual button 
               
               
                   
                 PCB 
                 Printed circuit board 
               
               
                   
                 PL 
                 Power lead 
               
               
                   
                 PP 
                 Pressure plate 
               
               
                   
                 PR 
                 Power ring 
               
               
                   
                 S 
                 Passenger seating 
               
               
                   
                 SA 
                 Security and alarm system 
               
               
                   
                 SG 
                 Security gate 
               
               
                   
                 V 
                 Vehicle 
               
               
                   
                 VAC 
                 Alternating current power source 
               
               
                   
                 VB 
                 Vehicle body 
               
               
                   
                 W 
                 Windshield