Abstract:
A reverse mode detection system provides an extremely inexpensive system which can be installed in seconds and which can be used by drivers to gauge the distance from the rear of the vehicle to an object, possible an array of objects, and to provide an optional combination of a soft alert or a distance reading which the user can optionally use to assist in reverse movements of an vehicle. One advantage of the system not before seen is some indication of the rear clearance space left available to the user in backing, and a multi storage calibration ability to enable more precise backing with regard to previously calibrated objects. The ability of the reverse warning and measurement system to actually be used on an vehicle with broad acceptance is based upon its mounting system, simplicity and energy sources which are self contained and conserving of power. The distance sensor is mounted in a frame shaped structure for attachment adjacent the license plate. The frame shaped structure will follow the license plate size which is typically a standard size for different countries. A transmitter associated with the reverse light wiring and illumination system can optionally activate the system in order to conserve battery power.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to the field of distance measurement and safe vehicle operation and more particularly to a user installable rearward looking distance measuring device with calibration which enables users to have an instant reading of the closeness of objects to the rear of a vehicle, while providing for installation by ordinary users.  
       BACKGROUND OF THE INVENTION  
       [0002]     A number of systems have been available for safety and accident prevention in automobiles. Almost all of the systems attempt to override driver control, and like most extremely complex innovations, are more likely to add problems to automobile ownership and increase automobile down time than the advantages are worth. As an example, an attempt has been made to provide radar devices which prevent a sleepy driver from approaching a parked car at high speed on the freeway. The problem with this system is that the car may lock the brakes when passing a parked car on the side of the freeway. This type of system has advances which attempt to focus the detection of an automobile to a direction directly head on to the automobile. This type of system has been fraught with problems, as no one who drives an automobile with this system would tolerate even one instance of a mis-triggering of an extreme stop on the freeway.  
         [0003]     Even more importantly, the degree of sophistication of such devices and the degree of integration into the automobile system, the required compatibility along with the labor make the system technically prohibitive and cost prohibitive. Other systems have used infrared to detect movement of humans about a parked vehicle, along with strategic placement of infrared sensors and a highly integrated display to indicate to the driver that the vehicle is being approached.  
         [0004]     Rearward relative object measurement has not been practically realized. The problem has been combining the method of distance measurement, the level of integration and the degree of operator attention and override involved. Integration into the braking system is impractical, but the degree of wiring and electrical integration remains problematic. Further, objects and structures which are added to a vehicle must generally comply with jurisdictional laws which govern the placement of objects onto the exterior of an automobile.  
         [0005]     None of the above solutions for a driver give any real advantage. It should be remembered that for humans operating any form of machinery, the human, his weaknesses and strengths must be factored in. In backing an automobile, the driver has an opportunity to go slowly, can stop the vehicle and use mirrors and other structures to assess his rearward progress, and perhaps may, if traffic allows, leave the vehicle to inspect the rearward progress. Therefore, the focus has erroneously been placed upon control of the braking system and perhaps in providing distracting warnings.  
       SUMMARY OF THE INVENTION  
       [0006]     The reverse mode detection system provides an extremely inexpensive system which can be installed in seconds and which can be used by drivers to gauge the distance from the rear of the vehicle to an object, possible an array of objects, and to provide an optional combination of a soft alert or a distance reading which the user can optionally use to assist in reverse movements. One advantage of the system not before seen is some indication of the rear clearance space left available to the user in backing. Because of the different types of vehicles and the different configurations of the rear areas of vehicles upon which the system may be mounted, a calibration feature allows users to calibrate the unit especially with regard to the type of object which the user is likely to encounter most often.  
         [0007]     As an example, where a driver needs to back into garage or a walled parking space, and especially the same space again and again, a readout can be calibrated based upon the placement of the automobile in a position in which the driver does not want to exceed and this position can be zeroed. Further, if this is one of three or four situations the driver is likely to encounter, he can store and retrieve the “zeroed” values for several such situations for maximum utility. Thus, where the driver wants to approach a wall in his work parking space, he can view the last foot or so of movement on his distance monitor and approach the optimum parking distance with precision.  
         [0008]     The ability of the reverse warning and measurement system to actually be used on automobiles with broad acceptance is based upon its mounting system. The mounting structure for the present system, enables quick installation. The distance sensor is mounted in a frame shaped structure for attachment adjacent the license plate. The frame shaped structure will follow the license plate size which is typically a standard size for different countries. In the United States, for example, the standard license plate size is about twelve inches wide and about six inches high. The U.S. license plates have mounting apertures, two at the top and two at the bottom of the license plate. The use of these apertures is recommended to insure that the frame structure (1) resists theft, and (2) maintains a stable fixed structure. An alternative option is for the use of powerful magnets in the frame structure itself which can be used in addition to the mounting apertures, and which can facilitate the use of the frame structure in a mobile sense, such as with rental cars or in other instances where the user is not expected to take the time for a permanent installation.  
         [0009]     The frame structure contains batteries and electronics which will both power a distance measuring device as well as a transmitter to transmit the distance information to the user inside the automobile. This topography of use enables several advantageous modes of operation. Batteries may be saved by providing a switching logic based upon (1) driver control of the on/off rear frame sensor, (2) a reverse motion sensor, (3) a periodic “ping” signal to see if there is any objects in the immediate vicinity, and (4) an inactivity mode which may use a sensor to enable a long cutoff span of time during which the vehicle is parked and/or not running. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]     The invention, its configuration, construction, and operation will be best further described in the following detailed description, taken in conjunction with the accompanying drawings in which:  
         [0011]      FIG. 1  is a plan view of a frame structure having peripherally inwardly extending attachment lugs for affixation adjacent and about the periphery of a license plate;  
         [0012]      FIG. 2  is a sectional view taken along line  2 - 2  of  FIG. 3  and illustrating one possible location of components inside the frame housing structure;  
         [0013]      FIG. 3  is a sectional view taken along line  3 - 3  of  FIG. 1  and illustrrates the depth of the frame housing structure and housing of electronic components;  
         [0014]      FIG. 4  is a plan view of a display unit with optional support plate for mounting upon a steering wheel column gear shift ring;  
         [0015]      FIG. 5  is a block diagram representation of one possible combination of the components of the automobile reverse warning and distance measurement system;  
         [0016]      FIG. 6  is a view of one possible embodiment of a transmitter tab sensor which both senses and uses the electrical connection to one of the backup lights to trigger activation of the reverse sensor set;  
         [0017]      FIG. 7  is a sectional view of the transmitter tab of  FIG. 6 , taken along line  7 - 7  of  FIG. 6 ;  
         [0018]      FIG. 8  is a closeup view of a flexible layered conductor system for deriving power through a voltage drop;  
         [0019]      FIG. 9  is a plan view of a further embodiment of the transmitter tab with a pair of conductors for deriving power through a voltage potential;  
         [0020]      FIG. 10  is a further embodiment of a transmitter tab for insertion into a bulb socket having a center conductor;  
         [0021]      FIG. 11  is a is a transmitter socket housing for use with a reverse lamp using wedge bulb;  
         [0022]      FIG. 12  is a sectional view taken along line  12 - 12  of  FIG. 11 ;  
         [0023]      FIG. 13  is a transmitter housing uses ultra thin traces for attachment to any ordinary reverse lamp exposed conductors;  
         [0024]      FIG. 14  is a bottom view of the transmitter housing seen in  FIG. 13 ; and  
         [0025]      FIG. 15  is a perspective view of a flexible optically driven transmitter which may be used by adhering to an ordinary reverse lamp. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0026]     In general, automobile reverse warning and distance measurement system  9  is shown within a frame housing structure  11  is provided which can fit adjacent a vehicle&#39;s license plate which is shown in background as having the license number 1DAKA. The format shown is an American Automobile license plate format having a dimension of about six inches high by about twelve inches wide. Other formats can be used, including the European standard of a much wider and less high license plate shape.  
         [0027]     The important element to note in  FIG. 1 , as well as the other drawings, is the accommodation of the space into which an automobile license plate  13 , and thus the frame housing structure  11  must fit. In extreme cases, and for some vehicles, the license plate  13  fits into an area restricted on all four sides. In other cases the license plate  13  can have an upper restriction only or a lower restriction only. As a result, to insure that the frame housing structure  11  can be used in all configurations of vehicle, the frame housing structure  11  has to have an outer dimension which generally matches and does not significantly extend beyond the license plate  13 .  
         [0028]     The height profile of the frame housing structure  11  in the direction of the viewer can be significantly extended except in cases where the frame housing structure  11  must fit partially underneath some restriction intended only for thin objects like the license plate  13  itself. These mounting restrictions are rare, however having most of the height profile on only one of the major length sides to give the frame housing structure  11  an ability to be mounted in two positions which are inverted with respect to each other.  
         [0029]     The following description corresponds to locations seen in the frame housing structure  11  shown in  FIG. 1 , but it is understood that the general principle is to supply all of the needed structure within the outer periphery of the license plate  13 . Further, the frame housing structure  11  can be provided as a single housing into which the user can emplace batteries, or it can have a plug in battery pack which preferably forms a continuous preferably non-identifiable connection with the frame housing structure  11 .  
         [0030]     In the view of  FIG. 1 , the frame housing structure  11  provides an opening  15  through which the license plate  13  is visible. Within the frame housing structure  11 , magnets may be mounted to be magnetically attracted to either the license plate  13  or any metal plate behind it. However, it is expected that the threaded members or other securing fasteners used in conjunction with the license plate apertures will similarly be used to connect with a series of four peripherally inwardly directed lugs  17 ,  19 ,  21 , &amp;  23 . The topological motif seen in  FIG. 1  includes both a periphery limited to the outer periphery of the license plate  13 , and an opening  15  which is as open as possible to avoid obscuring the information printed on the license plate  13 . Similarly, the lugs  17 ,  19 ,  21 , &amp;  23  are designed to be as narrow as possible and as limited in length as possible to enable engagement with securing members (not shown) which similarly engage a set of four through apertures  25  which are shown as extending completely through the lugs  17 ,  19 ,  21 , &amp;  23  and the license plate  13 . Further, depending upon the material chosen, one or more of the lugs  17 ,  19 ,  21 , &amp;  23  can be eliminated for simplicity and ease of mounting. For example, if only lugs  17 , &amp;  23  were present, and if the material of the frame housing structure  11  had sufficient integrity, two threaded members would be sufficient to hold automobile reverse warning and distance measurement system  9 .  
         [0031]     In most ordinary installations, both the frame housing structure  11  and the license plate  13  will be secured, the frame housing structure  11  secured onto the license plate  13  with threaded members having large, flattened profile heads. Where the frame housing structure is accessible from the outside, the lugs  17 ,  19 ,  21 , &amp;  23  are preferably oriented such that support lug support will help secure the frame member  11  against the license plate  13  so as to bolster the ability to enclose the components.  
         [0032]     The specifics of the outward profile of the frame housing structure  11 , which is in fact a housing for the internal electronics of the automobile reverse warning and distance measurement system  9 , can vary widely. Depending upon which techniques are chosen to sense the surroundings and which techniques are chosen to power the electronics, the outward appearance of the frame housing structure  11  may vary depending upon need. For example, some forms of electromagnetic radiation will transparently propagate through even a black plastic housing. For sensing white light (and the energy derived from it) some areas of the frame housing structure  11  may be transparent to visual light. Where the frame housing structure  11  is made of metal, another appearance may be dictated dependent upon the internals, and their ability to project and receive power and signals as necessary. The frame shape of the frame housing structure  11  can offer the advantages of a loop as well as a cylinder. Frame housing structure  11  somewhat lengthy cylindrical extent opens the possibility for serial arrangement of a wide array of components and sensors. The extended loop shape can be used to good advantage electromagnetically in the ability to form a wide variety of antennas from which, and into which signals may be propagated.  
         [0033]     To the left side of  FIG. 1 , a solar array  27  is shown extending vertically down the left side of the frame housing structure  11 . In the configuration shown, enough of the solar array  27  will be exposed regardless of which orientation the frame housing structure  11  is placed, such that the solar array  27  ends up on the right or left side. Further, the vertical extent of the solar array  27  insures that even if it is partially shaded from the sun that enough of it will be exposed to enable sufficient power to be obtained from light energy.  
         [0034]     On the top of the frame housing structure  11  one realization of an external antenna  29  is shown. External antenna can include a thin profile metal which is layered onto an insulating layer on top of the frame housing structure  11 . An external antenna  29  should be necessary perhaps only if the frame housing structure  11  is made of a material which would block the frequencies selected for use. Otherwise, an internal antenna could be used. An external antenna  29  may eliminate the need to worry about internal feedback and may be end fed or center fed antenna. External antenna  29  may be inset within a slot, and possibly covered with a thin layer potting material to protect it.  
         [0035]     On the right side of the frame member  11 , one possible configuration of sensor placement is shown as a pair of sensors including sensor  35  and  37 . Sensors  35  and  37  are seen as oval structures, but their location need not even be discernible from the exterior of the frame housing structure  11 . Sensors  35  and  37  are shown as separated to emphasize the inventive strategies which derive from incorporating automobile reverse warning and distance measurement system  9  into a frame housing structure  11 .  
         [0036]     First, where the sensors  35  and  37  are of the same type, the spaced apart location enables a more adequate vertical coverage. Where a license plate  13  mounting area is over a bumper, and with respect to the configuration shown in  FIG. 1 , at least one of the sensors, such as sensor  35  can survive to remain high over the lower bumper. Likewise, where a handle, light or other structure overlies the automobile reverse warning and distance measurement system  9  frame housing structure  11 , a sensor, such as sensor  37  can survive to remain free from obstruction.  
         [0037]     Where sensors  35  and  37  are sonic, the sensors  35  and  37  can be modulated to achieve a best combination for the mounting configuration. For example, if some object is near the upper sensor  35  creating “splatter” or multiple echoes, control circuitry (not yet shown) can combine to shift the operation to the sensor  37 . Further, where neither of the sensors  35  and  37  are interfered with, they can be used in tandem to produce the best verification of distance. Two sensors can be phased to “focus” upon the object being tracked. The “focus” effect can be almost instantaneous. If the action of the top sensor  35  gives a return time of t 1 , and if the bottom sensor gives a return time of t 2 , the sensors  35  and  37  can be “phased” to produce a combined effect.  
         [0038]     Sonic sensors, particularly operate by measuring the return time for a sonic pulse. The two sensors  35  and  37  can have phase delayed pulses of different frequency or of the same frequency to produce a higher intensity return signal in order to “track” an object, or to have its signal predominate over the others. Typically the closest signal is used, but where there is interference, or where an object which is changing its return time (such as an object moving with respect to the sensors), it can be phased to insure that it remains the highest priority return signal. Further, linear “window” openings of return times can be used to blank out unwanted and spurious signals by providing detection only within a window corresponding to the return time of interest (which relates to objects within a defined range from the sensors  35  and  37 ).  
         [0039]     Further, controlled and phased doppler action can be used which further focusses upon moving objects, especially under the assumption that an object moving toward the sensors  35  and  37  is of most pronounced interest. To further illustrate an example for horizontal difference, a pair of sensors  39  and  41  are seen along the bottom of the frame housing structure  11 . Sensors  39  and  41  have greater separation and are capable of a grosser degree of phasing. Further, where the approaching object of interest lies to one side of the vehicle, such phasing will enable more accurate tracking. Further, and especially when backing up for parallel parking, the point of closest approach may be to one side, and phasing will enable the closest point to be concentrated upon.  
         [0040]     In the configuration seen in  FIG. 1 , the automobile reverse warning and distance measurement system  9  frame housing structure  11  can be tried in both its right side up configuration, as well as inverted to see if either position works better with some indication of placement based upon potential obstruction or interference. Further, although shown with two sets of separated sensors,  35 ,  37 ,  39  and  41 , an automobile reverse warning and distance measurement system  9  can have several sensors and located multiply within the frame housing structure  11 .  
         [0041]     Where electromagnetics is used, the sensors,  35 ,  37 ,  39  and  41  can emit infrared light or pulsed light with a measurement of light return time to indicate distance. Again, doppler techniques can be used as well as phasing and smart sensing with the use of computer control.  
         [0042]     Referring to  FIG. 2 , a sectional view, looking into the space within the frame member  11  shows one of several possibilities in terms of the number and type of possible sensors  35 ,  37 ,  39  and  41  and other components are is shown. At the top of the frame housing structure  11  are a series of batteries  45  which may be “AAA” sized batteries for their small diameter and ability to fit within a linear section of the frame housing structure  11 , and may preferably be re-chargeable, especially where the solar array  27  is to be used for supplying re-charging energy.  
         [0043]     It is important for the batteries  45  to be in a position to be protected from moisture and the elements. Note that the placement of sensors  35 ,  37 ,  39  and  41 , as well as the batteries  45  are preferably arranged so that the frame housing structure  11  can be mounted right side up or upside down without impairing the operation of the automobile reverse warning and distance measurement system  9 .  
         [0044]     To the right, an electronics section  47  is shown in electrical communication with sensors  35 ,  37 ,  39  and  41 . Each of the sensors  35 ,  37 ,  39  and  41  may include a self contained energy emitter and energy receiver. In the alternative the placement of the sensors  35 ,  37 ,  39  and  41  may include different placement for the sensor energy transmitters, for example one of sensors  35  and  37  as a transmitter and the other of sensors  35  and  37  as a receiver. In some cases having an energy transmitter displaced a distance from the energy receiver can provide advantages. Likewise, the use of several sensors  35 ,  37 ,  39  and  41  placed around the automobile reverse warning and distance measurement system  9  frame housing structure  11  can provide further optimization.  
         [0045]     In addition, any electromagnetic sensors which operate within the infrared range can also give an indication of human movement when the automobile reverse warning and distance measurement system  9  is on. A special alarm can be used when infrared sources traverse laterally with respect to the sensors  35  and  37  as a recorded trasversing movement would not be expected during backing a vehicle unless the vehicle was backing up in an area free of obstruction. Most reverse operation of a vehicle is done either in close quarters, at a gradually changing angle (as in parallel parking), or in a more open space generally straight (like backing into a parking space). Where such anoptional infrared type sensors are used, a transmitter may provide, separately or in combination, infrared illumination pulses for measuring distances, as well as a zoned sensor for giving an indication of human movement when the automobile reverse warning and distance measurement system  9  is on. Zoning can be achieved by an additional detector having a fresnel lens, or other zoned lens oriented to focus detection activity on an object moving from left to right. A special alarm, such as a separate computational threshold, can be used when infrared sources traverse laterally with respect to the sensors  35  and  37  as this would not be expected during backing a vehicle unless the vehicle was backing up in an area free of obstruction.  
         [0046]     To the left of batteries  45 , a transmitter controller  51  is shown. Transmitter controller  51  is connected to the batteries  45  and to the electronics section  47 . The electronics section  47  may be dedicated to the operation of the sensors  35 ,  37 ,  39  &amp;  41 . The Transmitter controller  51  is preferably dedicated to receive an indication of distance from the electronics section  47  and to transmit the information through either an internal antenna (not shown) if the frame housing structure  11  is transparent to electromagnetic transmission energy, and to external antenna  29  if the frame housing structure  11  is not transparent to electromagnetic transmission energy.  
         [0047]     Even though the automobile reverse warning and distance measurement system  9  frame housing structure  11  will likely be mounted in a direction facing away from the rear of a vehicle, with a receiving unit (to be described) being in the opposite direction, the electromagnetic transmission waves will be able to reflectively enter the passenger compartment of the vehicle by reflection off of other objects, as well as the entry into the rear window of the vehicle. It is remembered that near field transmissions are enabled to more directly propagate into the passenger space of a vehicle. A pair of conductors extending from the transmitter controller  51  may connect to the solar array  27  which is shown as removed. The control of the charging of the batteries  45  may be controlled by either the transmitter controller  51  or by the electronics section  47 . In addition, where the transmitter controller  51  is a transceiver controller  51 , it can be used to provide a manual on-off function. In order to save power, it may be desirable to insure that the  
         [0048]     automobile reverse warning and distance measurement system  9  remains in an inactive state until and unless the driver wishes to activate it. Other awakening mechanisms can be employed to signal the automobile reverse warning and distance measurement system  9  to begin measurements.  
         [0049]     Referring to  FIG. 3 , one possible side view of the automobile reverse warning and distance measurement system  9  frame housing structure  11  is seen along line  3 - 3  of  FIG. 2 . The view of  FIG. 3  emphasizes that the depth of the frame housing structure  11  can be much deeper than its peripheral width. The depth is seen as being about two to three times the peripheral width, and supports two lines of batteries  45 . The extension of the lugs  19  and  23  are clearly seen, along with apertures  25  for mounting the frame housing structure  11 . At the bottom, one of the sensors  41  is seen. Note that the sensor is positioned on the rearward face of the frame housing structure  11 , so that it will have a more rearward exposure and better, less obstructed wide angle coverage to the rear of the vehicle.  
         [0050]     Referring to  FIG. 4 , a driver&#39;s display unit  71  is shown has having an upper housing  73  and a lower optional support plate  75  having a lower curved surface  77 . Other features on the display unit  71  include a liquid crystal display screen  79  (which may be illuminated) which may have a physical representation of a vehicle and an angular representation of the sweep area scanned by the automobile reverse warning and distance measurement system  9 . Where the capability is present, the screen  79  may show the distance and location of several objects, and not just the closest object. It may also have the ability to produce a visual representation of an object, shown by a small symbol “+”  81  shown on the screen  79 . Screen  79  should also be enabled to indicate the distance of the closest object in an alpha numeric display portion of the screen seen as “11.3 FT”.  
         [0051]     Other aspects of the display unit  71  include an off/on switch  83 , a tilt on/off switch  85  and a calibrate on/off switch seen with the words “cal on” and labeled  87 . A minimalist input function set might include buttons labeled as a minus button, “(−)”  91 , a plus button “+” button  93 , an “S” button  95  and a “P” button  97 .  
         [0052]     In addition, for dedicated operation, a center close mercury switch  99  is shown in a cut away section of the upper portion of the display unit  71 . Most automatic vehicles have a collar which surrounds the steering column and which moves when the selector column moves. The position when going from “Drive” to “Reverse” involves a slight movement of the collar a couple of degrees to the left. When placed in tilt on mode, the automobile reverse warning and distance measurement system  9 , which includes the display unit  71 , will remain shut off to conserve power. When the automobile drive lever is placed in Reverse, the display unit  71  achieves a centered, upright position, and the electronics are switched on. The switching on of the display unit  71  may include a sampling override which keeps the automobile reverse warning and distance measurement system  9  functioning despite any temporary movement of the automobile which would cause the center close mercury switch  99  to temporarily open, even while the display unit  71  is upright, such as lateral forces from movement of the automobile.  
         [0053]     Likewise, a temporary movement override can be used to ignore momentary closure of the switch from lateral force due to automobile cornering. Because the angular movement of the driving column is so slight, the center close mercury switch  99  will necessarily be of slight angular curvature. As another feature to combat unintentional triggering during cornering, a set of left side and right side contacts can provide an over ride to keep the unit shut off for at least one second as the mercury bead  101  moves between the center contacts  103 , a set of right contacts  105  and a set of left contacts  107 .  
         [0054]     In normal usage, a parked car will cause the mercury bead  101  to move to position  107  and will insure that the unit is off, that the automobile reverse warning and distance measurement system  9  upper housing  73  electronics remain off and that the electronics within the frame housing structure  11  are not signaled and remain un-activated. When in drive, the upper housing  73  will be tilted to the right, and the contacts  105  will normally remain closed while sensing the presence of the mercury bead  101  while automobile straight travel is achieved.  
         [0055]     However, normal driving with normal cornering will cause the mercury bead  101  to move back and forth. Hard cornering will cause the bead  101  to close the contacts  105  and  107 . Highway driving will cause the bead to generally keep contact  105  closed, but may cause the bead to move to the center contact  103  momentarily. Because of the one or two second over ride, a lane change which might perhaps enable the bead  101  to remain in residence on the contacts  103  for almost a second, will not cause the electronics within the display unit  71  to either start up, nor will it enable the electronics within the display unit  71  to send a signal to the electronics (electronics section  47  or transmitter controller  51 ) within the frame housing structure  11 .  
         [0056]     All that a user need do is use an adhesive foam pad to mount the support plate  75  onto the gear change collar associated with the gear shift lever in the upright position, when the ignition is off and when the gear shift lever is moved to park. Such integration will enable the display unit  71  of the automobile reverse warning and distance measurement system  9  to become an essentially permanent part of the driver&#39;s instrumentation. Because the display unit  71  is small and mounted forwardly with respect to the other instruments in an automobile, no obstruction will be had with respect to the other instruments in the auto.  
         [0057]     The tilt on switch  85  enables the tilt feature. A simple shutting off of the tilt feature permits complete manual operation with the on/off switch  83 . In this way, the same upper housing  73  can be used in a more permanent and a less permanent mode. The upper housing  73  may be made detachable from the lower housing  75  to facilitate battery change or to enable the display unit  71  to be used by others. The detachability feature is especially useful for calibration.  
         [0058]     During calibration, the “cal on” switch  87  is moved to the on position. Because of the mobility of the display unit  71 , the calibration can be performed outside the vehicle. As an example, suppose a driver wanted to make certain that he parked a known distance from an object, and positioned the automobile the exact distance from the object desired. The operator could press the program button  97  and by using the “(−)” and “+” buttons come to a program storage location where the calibration is to be entered. A +/0/− convention could be used in liquid crystal display screen  79  in the program location for future reference to help the driver achieve the exact location he selected during the calibration process. If the location was a wall, he would be able to move to the storage area where the calibration occurred and then moved to the desired location, precisely, every time.  
         [0059]     The calibration is also used because a variety of sensors, and conditions may give a different three dimensional reading for each type of object. A brick wall may have a slightly different reading than a vertical pole. An overhang may give a weak reading, and the calibration feature will enable the unit to sense the desired calibration distance based upon a variety of signal conditions, and not just the most prominent return from the closest object. The calibration selection, for example, may use a combination of one sonic sensor and one infrared time reflex domain sensor with the calibration based upon a pair of targeted distances as well as a comparison ratio between them.  
         [0060]     The foregoing being an example of a focussed calibration, the programming of the electronics within the liquid crystal display screen  79  is also ideally subject to a more general calibration especially since the rearward looking profile of each automobile is different. Some license plates  13 , and therefore the frame housing structure  11 , will be mounted at different angles on some vehicles, and others have varying restrictions. Calibration may include a first open field calibration where the vehicle is parked completely away from all obstructions in order to get a base line to account for any signal distortion with respect to the mounting limitations, and a second calibration where the vehicle is backed against and touching a wall. This will enable a real conditions default calibration based upon the distance from the most rearward end of the bumper of the vehicle and the inward displacement of the frame housing structure  11 .  
         [0061]     Although it is likely that the objects encountered will not always have a flat wall profile, the base line calibration lets the operator know at least a base line distance. In the case of another vehicle having a bumper protruding about 5 inches and where the main part of the vehicle behind the vehicle equipped with the automobile reverse warning and distance measurement system  9  is closer to the frame housing structure  11  than the bumper, the driver of the car equipped with the automobile reverse warning and distance measurement system  9  may make contact with the other rearward vehicle a few inches before the previously indicated calibrated “zero” distance. This may happen for any lower protruding object which protrudes low and provides a an open upper clearance.  
         [0062]     However, the automobile reverse warning and distance measurement system  9  will have its greatest use where drivers can avoid hardened objects like walls and steel posts. Further, however, where the automobile reverse warning and distance measurement system  9  will be used more often with parking, a calibration can be performed based upon a measurement in front of a vehicle which is expected to be encountered. One of the expected uses of the keys  91 - 97  is to enable the storage of calibration profiles. The user can ideally switch from one calibration profile to anther depending upon the situation encountered. In this manner, the user can select from a number of pre-stored calibration profiles to enable a much more exacting operation of his vehicle.  
         [0063]     Of all the situations encountered, the parallel parking situation will likely have the greatest individual variance from a standard calibration mode, and because the adjacent automobiles are expected to vary the most in terms of their forward shape profile, the driver will have to be more careful and rely less on the indication appearing on the liquid crystal display screen  79 . However, inasmuch as the parallel parking typically involves a very low movement velocity and some intended bumping, and driver feel, the automobile reverse warning and distance measurement system  9  will probably not have as high a driver utility in this instance. The expected highest incidences of use involve darkened spaces into which the vehicle is backed into and unknown areas into which the vehicle is backed. The need for the automobile reverse warning and distance measurement system  9  is especially high where a driver goes from bright daylight to a darkened garage area and where the driver&#39;s eyes have not sufficiently adjusted to a level which will permit judging the distance.  
         [0064]     Referring to  FIG. 5 , a block diagram outlining one possible topology for the automobile reverse warning and distance measurement system  9 . Elements shown already include sensors  35 ,  37 ,  39  &amp;  41 . An additional sensor  115  represents multiple other sensors which may exist singly or in integration with the sensors  35 ,  37 ,  39  &amp;  41 . Note that the solar cell  27  and battery  45  may be connected directly or through the electronics section  47  and or transceiver controller  51 . Either of the electonics section  47  and or transceiver controller  51  may include voltage increase circuitry. The upper part of  FIG. 5  includes a lot of structure seen in  FIGS. 1 and 2 . The other possible block structures associated with the upper housing  73  includes a display controller  121  which may preferably be a single microprocessor control circuit for all of the components of the display unit  71 . Display controller  121  is shown is in connection with the LCD display  79 , and the mercury switch  99 . Other components not shown earlier include a battery  123  and a transceiver  125  controllably connected to the display controller  121  and having an antenna  127  connected to the transceiver  125 . All of the sleep functions and other programming functions associated with operation of the display unit  71 , including switches  83 - 97  will preferably be controlled by the display controller  121 .  
         [0065]     One desirable implementation of the automobile reverse warning and distance measurement system  9  is to provide for limited activation of the system. An automatic activation is always preferred, but beyond the mounting of the display unit  71  on the gear shift column, the user will have to take installation steps beyond the simple affixation of a license plate frame. During reverse operation of a functioning vehicle, power is supplied to the backup lights, which are typically white light incandescent emitters. Access to backup lights are supplied to ordinary users typically through the trunk. An open trunk typically exposes an internally located lamp housing space into which fits a backup lamp socket assembly. A burned out light is typically replaced by the user by opening the trunk, pulling out the lamp socket assembly from its specially designed lamp housing space, and then replacing the lamp in the lamp socket manually, and then replacing the lamp socket assembly by insertion into its opening into the lamp housing space.  
         [0066]     Placing the automobile into reverse results in two measurable aspects associated with the lamp housing space. First, when the automobile is running and placed into reverse mode, electricity is supplied to the reverse lamps. Second, the area within the lamp housing space is instantly bathed in bright white light. Both of these measurable aspects of the reverse lamp operation can be used to activate the automobile reverse warning and distance measurement system  9 .  
         [0067]     What is to be avoided if possible is to cause the ordinary user to change the electrical system of the vehicle by tapping in or other potentially dangerous activity. Reverse lamps have many configurations, the top three being center conductor, parallel spaced apart conductors and wedge socket. One device which can use the electrical power supplied without the necessity for doing more than would be required for a bulb change for parallel conductors is the use of a very thin transmitter tab  151  as is shown in  FIG. 6 . Transmitter tab  151  includes an open conducting area  153  which exposes a flexible, deformable conductor  155  which may be a sandwiched material.  
         [0068]     A circuit located inside the transmitter tab  151  need only transmit a very short range signal to a receiver in the electronics section  47  in order to instruct it to activate the automobile reverse warning and distance measurement system  9 . It should be remembered that in this mode, it may be preferably for the transmitter controller  51  to also transmit to the display unit  71  to activate it as well. One mode for transmission of the transmitter tab  151  may be by a simple square wave, carrying no intelligence other than its signal.  
         [0069]     Power may be derived by placement of the transmitter tab  151  into the base of a lamp socket manually followed by the replacement of the bulb. The open conducting area  153  can be centered where the bulb has a center conductor, or it may have an additional open space  157  where a pair of side by side conductors are used. In the case of side by side conductors, the two knobs on the bottom of a lamp will register the transmitter tab  151  and help orient it in the socket.  FIG. 7  illustrates a cross sectional view with the possible deformation of the deformable conductor  155  shown in dashed line format.  
         [0070]     In terms of taking power, a transmitter within the transmitter tab  151  can be voltage or current driven. Where a single membrane material as a deformable conductor  155  is used, a sandwich of materials produces a slight voltage drop as current passes through the material. An example is seen in  FIG. 8  which shows one possible configuration for the deformable conductor  155  as having an upper near zero resistance layer  161 , a middle slight resistance layer  163 , and a lower near zero resistance layer  165 . Where current flows through the deformable conductor  155 , a voltage will be developed between the layers  161  and  165  which may be sufficient to drive a transmitter (not shown).  
         [0071]     An alternative embodiment is seen in  FIG. 9 , where a transmitter tab  171  is voltage driven and uses a pair of conductors  173  and  175  which are housed within open conducting areas  177  and  179 , respectively. In this configuration, the transmitter would operate from the voltage differences between the two conductors  173  and  175 . As an alternative, conductor  173  is shown as being made of a more resilient metal with a star cutout pattern which may still make contact with a lamp terminal while permitting the bulk of the lamp terminal to pass through.  
         [0072]     A further alternative embodiment is seen in  FIG. 10  for a center conductor lamp. A transmitter tab  181  is thin and circular for fitting within a lamp socket. The transmitter tab  181  has a periphery which will contact the metal inside area of a lamp socket (not shown). In addition, it may have a thin deformable projection  183  to further insure that contact is made with the inside of the lamp socket (not shown). At the center of the transmitter tab  181  is a conducting area  185  with a conductor  187  which may be a deformable conductor or it may be a star shape (shown by the dashed line indicator) to permit contact with the center conductor of a lamp and a lamp socket (both not shown).  
         [0073]     The wedge type lamp often has conductors which are build into the glass lower envelope of the lamp and which may protrude externally above the neck of the extent of the insertion stop located on the lamp. In this case, a thin, push through clip could be used to capture contact from the bulb. Referring to  FIG. 11 , a transmitter socket housing  191  has a side volume  193  for housing the electronics for the transmitter circuitry, and a central through opening  195  within which a pair of conductors  197  and  199  can be seen.  
         [0074]     Referring to  FIG. 12 , a sectional view taken along line  12 - 12  of  FIG. 11  illustrates the very thin profile of the transmitter socket housing  191  and illustrates the inside of the electronics volume  193  and shown with electronic circuitry  201  inside.  
         [0075]     Referring to  FIG. 13 , a more universal transmitter can be provided with conducting adhesive contacts for fitting onto any type of reverse bulb. A transmitter housing  211  with electronic circuitry inside has a pair of extremely thin, flexible circuit traces, including a first trace  213  and a second trace  215 . Each of the traces  213  and  215  are completely insulated by an outer covering of flexible circuit material  219  or the like and is extremely flat. It is contemplated that the traces  213  and  215  may be attached to any exposed conductor of a lamp and inserted back into the lamp&#39;s socket with adequate clearance.  
         [0076]     Each of the traces  213  and  215  may be exposed on one side of an expanded end of the circuit material, and may be covered with a release strip until ready for installation. The ends of the traces are expanded into a slightly enlarged circular area  221  supported by a slightly enlarged partially circular area  223  of the flexible circuit material  223 . A star cut  225  may be made at the time of manufacture into the enlarged circular areas  221  to facilitate a fit over any post type plug in terminals. The exposed slightly enlarged circular areas  221  of the traces  213  and  215  may have conductive adhesive applied. Referring to  FIG. 14 , a side profile of the transmitter housing  211  of  FIG. 13  is illustrated. A release layer  231  is used to expose the conducive adhesive and exposed slightly enlarged circular areas  221  of the traces  213  and  215 .  
         [0077]     For installation, a user simply removes his reverse bulb and identifies some exposed area of the conductors of the bulb. Where a prong or other conductive structure has a small area, it can be pushed through the star cut  225  far enough to insure that it makes contact through to the other side. Where a needle shaped prong is exposed, the star cut will allow the prong to slip through, maintaining electrical contact while not covering the remainder of the prong needed for direct electrical contact between the prong and the lamp socket.  
         [0078]     Lastly, and referring to  FIG. 15 , a photocell transmitter  241  is shown. A release layer  243  exposes a face  245  of a flexible material having a photocell  247  at the center. The face  245  is preferably adhesive coated so that it can be adhered advantageously to the rear side of the reverse bulb. An electronics pod  249  is seen which houses a transmitter and other circuitry. The adhesive and flexible structures enable the photocell transmitter  241  to be positioned closely adjacent the bulb in a position to receive not only photo-electric energy, but to receive the optimum net difference sense between the bulb being on and off. Circuitry within the electronics pod  249  can also be used to sense the step rise and step fall in light levels so that it can start and stop transmitting at the proper time. The circuitry may have charge storage capacity so that it can act more intelligently on startup, such as by actively detecting a threshold which must be exceeded to trigger a radio signal. With the photocell transmitter  241 , the automobile circuit need not be tapped in any form.  
         [0079]     While the present invention has been described in terms of a distance sensing and warning system which provides automobile drivers with an indication of objects to the rear of their vehicle, and especially for enabling drivers to, with precision, repeat the parking process using an indicator in addition to other visual observation, including mirrors and a turn around view through the rear vehicle window, the present invention may be applied in any situation where the degree of integration of a system is matched with the needs of a user and designed to facilitate actual use at a helpful level rather than a system wide integration to actually lower utility.  
         [0080]     Although the invention has been derived with reference to particular illustrative embodiments thereof, many changes and modifications of the invention may become apparent to those skilled in the art without departing from the spirit and scope of the invention. Therefore, included within the patent warranted hereon are all such changes and modifications as may reasonably and properly be included within the scope of this contribution to the art.