Apparatus for searching for sensed object

An apparatus for searching for a sensed object which is capable of immediately finding the direction in which a movable sensed object is present, from the contents displayed on an operation unit at hand. The searching apparatus includes a portable operation unit, an absolute direction sensor contained in the operation unit and generating an absolute direction signal which indicates an absolute direction, a removal sensor for automatically sensing a removal of the operation unit from the sensed object, a displacement sensor for sensing the state of displacement of the operation unit to generate displacement information, a controller generating direction indicating information which indicates the direction in which the sensed object is present, based on the displacement information and the absolute direction signal, a display for displaying contents of the direction indicating information; and a manual operation element for controlling the contents displayed on the display through the controller.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to an apparatus for searching for a sensed 
object, and particularly to an apparatus for searching for a sensed object 
in which the direction to the present position of an object, e.g., a 
movable object such as an automobile, is displayed on a portable operation 
unit on the basis of the displacement locus of the operation unit after 
the operation unit is removed from the object. 
2. Description of the Related Art 
When an automobile is parked in an inexperienced place, when the driver 
leaves the parked automobile on business for a long time or goes 
relatively far away from the place where the automobile is parked, and 
when the driver returns to the place where the automobile is parked after 
the business is finished, in some cases, the place where the automobile is 
parked cannot be found, and the driver has difficulties in finding the 
parked automobile. 
Such a state is frequently created when an automobile is parked in a 
strange large-scale parking lot, for example, when many temporary parking 
lots are separately located for persons to see events such as a sample 
fair, an exhibition and a festival, or when a driver parks an automobile 
in a multistory parking lot where many cars can be parked on each of 
stories and the driver runs the driver's own car in and out of the parking 
lot. This state is also created when an automobile is parked on a road in 
a place where roads are complicated, and there is nothing as a guide in 
the vicinity of the parked automobile. 
When a driver loses sight of a place where the driver's own automobile is 
parked, as a matter of course, the driver must search for the place where 
the automobile is parked. When the driver searches for the place where the 
driver's own automobile is parked, if a search range is defined, the 
parking place can be searched for by spending time to some extent even if 
the search range is relatively wide. However, when the search range is not 
necessarily defined, for example, when one of a plurality of parking 
places where an automobile is parked is not found, as described above, or 
a story in a multistory parking place where the automobile is parked is 
not found, there occurs a serious situation in which much time is required 
for searching for the parking place. 
It is also dangerous and obstructive of running of other automobiles to 
walk about a parking place for searching for the parked automobile. 
SUMMARY OF THE INVENTION 
The present invention has been achieved in consideration of the 
above-described situation, and an object of the invention is to provide an 
apparatus for searching for a sensed object which is capable of 
immediately finding the direction in which a movable sensed object is 
present, from contents displayed on an operation unit at hand. 
In order to achieve the object, in accordance with an embodiment of the 
present invention, there is provided an apparatus for searching for a 
sensed object comprising an absolute direction sensor contained in a 
portable operation unit and generating an absolute direction signal which 
indicates an absolute direction; a removal sensor for sensing a removal of 
the operation unit from the sensed object; a displacement sensor for 
sensing the state of displacement of the operation unit after the 
operation unit is removed from the sensed object to generate displacement 
information; an arithmetic controller for generating direction indicating 
information which indicates the direction in which the sensed object is 
present, on the basis of the displacement information and absolute 
direction signal; and a display for displaying contents of the direction 
indicating information. 
In accordance with another embodiment of the present invention, there is 
provided an apparatus for searching for a sensed object comprising an 
absolute direction sensor contained in a portable operation unit and 
generating an absolute direction signal which indicates an absolute 
direction; a removal sensor for automatically sensing a removal of the 
operation unit from the sensed object; a displacement sensor for sensing 
the state of displacement of the operation unit after the operation unit 
is removed from the sensed object to generate displacement information; an 
arithmetic controller for generating direction indicating information 
which indicates the direction in which the sensed object is present, based 
on the displacement information and the absolute direction signal; a 
display for displaying contents of the direction indicating information; 
and a manual operation element for controlling the contents displayed on 
the display through the controller. 
In accordance with a further embodiment of the present invention, there is 
provided an apparatus for searching for a sensed object comprising an 
absolute direction sensor contained in a portable operation unit and 
generating an absolute direction signal which indicates an absolute 
direction; a charging battery serving as a power source of the operation 
unit; a displacement sensor for charging the charging battery when the 
operation unit is loaded on the sensed object provided with a charger and 
for sensing the state of displacement of the operation unit by operating a 
manual reset to generate displacement information; an arithmetic 
controller generating direction indicating information which indicates the 
direction in which the sensed object is present, on the basis of the 
displacement information and the absolute direction signal; and a display 
for displaying contents of the direction indicating information. 
In accordance with a still further embodiment of the present invention, 
there is provided an apparatus for searching for a sensed object 
comprising an absolute direction sensor contained in a portable operation 
unit and generating an absolute direction signal indicating an absolute 
direction; a charging battery serving as a power source of the operation 
unit and having a terminal; a displacement sensor for charging the 
charging battery when the operation unit is loaded on the sensed object 
provided with a charger and for sensing the state of displacement of the 
operation unit by operating a manual reset to generate displacement 
information; an arithmetic controller generating direction indicating 
information which indicates the direction in which the sensed object is 
present, on the basis of the displacement information and the absolute 
direction signal; and a display for displaying contents of the direction 
indicating information; wherein when the terminal of the operation unit is 
removed from the charger of the sensed object, the voltage supplied from 
the charger is cut off to automatically return the coordinate position of 
the displacement sensor to an initial state. 
In the above-described constructions, when an operator (a searcher of the 
sensed object, for example, the owner of an automobile) leaves the sensed 
object (for example, an automobile), if the operator has the operation 
unit, the removal sensor of the operation unit automatically senses a 
removal from the sensed object, and the displacement sensor successively 
senses the operation unit in the course of displacement thereof after the 
operation unit is removed from the sensed object to generate displacement 
information. The controller generates the direction indicating information 
which indicates the direction in which the sensed object is present 
relative to the operation unit, based on the absolute direction signal 
obtained from the absolute direction sensor and the displacement 
information obtained from the displacement sensor. The contents of the 
direction indicating information are displayed on the display. Thus, the 
operator (a searcher of the sensed object, for example, the owner of an 
automobile) can immediately know the direction in which the sensed object 
(for example, an automobile) is present (for example, the direction to a 
parking place) by seeing the contents of the displayed direction 
indicating information on the spot.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Embodiments of the present invention will be described in detail with 
reference to the drawings. 
FIG. 1 is a block diagram showing an apparatus for searching for a sensed 
object in accordance with an embodiment of the present invention. In this 
embodiment, the sensed object is an automobile. 
In FIG. 1, the apparatus for searching for a sensed object comprises a 
portable operation unit 1 which is generally carried by the owner of the 
automobile. The operation unit 1 contains an absolute direction sensor 2, 
a removal sensor 3, a displacement sensor 4, an arithmetic controller 5 
comprising a microcomputer or an integrated circuit (IC), a display 6 
comprising a liquid crystal element, and a manual operation element 7. In 
the operation unit 1, the arithmetic controller 5 is connected to the 
output terminals of the absolute direction sensor 2, the separation sensor 
3, the displacement sensor 4 and the manual operation element 7 so that 
the arithmetic controller 5 displays positional information on the display 
6 in accordance with the outputs from these elements. The positional 
information may be output as a speech by using a speech converter such as 
a speaker or the like in place of the liquid crystal display 6. In this 
embodiment, the absolute direction sensor 2 comprises a geomagnetic 
sensor, and the displacement sensor 4 comprises a displacement sensing 
member such as an acceleration sensor or a pendulum. 
The apparatus for searching for the sensed object (automobile) constructed 
as described above is used when the operator cannot find a place where the 
operator's own automobile 50 was parked. In this case, the operator 
searches for the operator's own automobile 50, as described below. 
When the owner of the automobile 50 parks the automobile 50 in a parking 
place and leaves the automobile 50, as shown in FIG. 3, the owner carries 
the portable operation unit 1. At this time, the removal sensor 3 of the 
operation unit 1 automatically senses removal of the operation unit 1 from 
the automobile 50 and generates a removal sensing signal which is then 
supplied to the arithmetic controller 5. The removal sensing signal can 
appropriately be generated. For example, the removal sensing signal may be 
generated when the operation unit 1 is removed from a predetermined 
storage place in the automobile 50, or when some signal constantly 
obtained in the automobile 50 is not sensed. 
The arithmetic controller 5 resets the rectangular coordinate position of 
the displacement sensor 4 to a reference coordinate position (0, 0) by the 
removal sensing signal supplied thereto, as shown in FIG. 4. After the 
coordinate position of the displacement sensor 4 is reset to the reference 
coordinate position (0, 0), the displacement of the position of the 
operation unit 1 relative to the automobile 50, i.e., the displacement of 
the position of the owner of the automobile who carries the operation unit 
1, relative to the automobile 50, is successively sensed by the 
displacement sensing member such as an acceleration sensor or the like to 
generate displacement information which is then supplied to the arithmetic 
controller 5. If the displacement of the position of the owner of the 
automobile relative to the automobile on the basis of the reference 
coordinate position (0, 0) of the displacement sensor 4 is f(t), and the 
displacement of the displacement sensing member such as an acceleration 
sensor, which is contained in the displacement sensor 4 of the operation 
unit 1, is x(t), the following equation is established: 
##EQU1## 
wherein .epsilon. and n are each a constant. Assuming that x=0 at t=0 or 
x.noteq.0 and (dx/dt)=0 at t=.tau., displacement f is represented as 
follows: 
##EQU2## 
The displacement f of the position of the owner of the automobile relative 
to the automobile can be calculated from displacement x(t) of the 
displacement sensing member such as an acceleration sensor or the like. 
The controller 5 performs a necessary operation based on the displacement 
information supplied from the displacement sensor 4, and the absolute 
direction signal supplied from the absolute direction sensor 2 comprising 
a geomagnetic sensor, e.g. the absolute direction signal which indicates 
due north, to generate direction indicating information which indicates 
the direction in which the automobile 50 is present, with respect to the 
position of the owner of the automobile (the position of the operation 
unit 1). 
When the owner of the automobile directs the display 6 to display the 
direction indicating information by operating the manual operation element 
7 of the operation unit 1 in order to know the present position of the 
owner's own automobile 50, the controller 50 supplies the present 
direction indicating information to the display 6 based on the operation 
of the manual operation element 7. As a result, the contents of the 
direction indicating information supplied, i.e., the direction to the 
present position of the automobile 50, the approximate distance thereto, 
etc., are displayed. 
The owner of the automobile can immediately know the direction to the 
position of the automobile 50 and the distance thereto on the basis of the 
position of the owner by seeing the contents displayed on the display 6 of 
the operation unit 1, without the need for searching for the parked 
automobile 50 by walking about. 
FIG. 2 is a block diagram showing details of the embodiment shown in FIG. 
1. 
In FIG. 2, reference numeral 10 denotes a manual reset; reference numeral 
13a, a battery terminal; reference numeral 13b, a battery power source; 
and reference numeral 13c, an automatic switch. Components equivalent to 
the components shown in FIG. 1 are denoted by the same reference numerals. 
As shown in FIG. 2, the operation unit 1 comprises a geomagnetic sensor 6 
serving as an absolute direction sensor, a separation sensor 3, an 
acceleration sensor 4 serving as a displacement sensor, CPU 5 serving as 
an arithmetic controller, a liquid crystal display 6 serving as a display, 
an operation switch 7 serving as a manual operation element, and a manual 
reset 10. The removal sensor 3 comprises a battery terminal 13a, a battery 
power source 13b and an automatic switch 13c. 
The searching operation of this embodiment will be described in further 
detail below with reference to FIG. 2. 
When the owner of the automobile is in the automobile, the operation unit 1 
is placed at the predetermined storage position in the automobile 50. At 
the storage position, the battery charger 5 is installed for constantly 
supplying a source voltage to the battery charger 13b of the operation 
unit 1 through the battery terminal 13a. 
When the owner having the operation unit 1 leaves the automobile 50, i.e., 
when the operation unit 1 is removed from the predetermined storage 
position in the automobile 50, the voltage supplied from the battery 
charger of the automobile to the battery power source 13b through the 
battery terminal 13a is cut off, and the battery charger is switched to 
the battery power source 13b in the operation unit 1. The automatic switch 
13c automatically senses the removal of the operation unit 1 from the 
predetermined storage position in the automobile and generates the removal 
sensing signal which is supplied to the CPU 5. When the removal sensing 
signal is supplied to the CPU 5, the CPU 5 automatically resets the 
coordinate position of the acceleration sensor 4 to (0, 0). 
A manual reset 10 may be provided for permitting manual reset in place of 
automatic reset. If the manual reset 10 is provided, when the operation 
unit 1 is loaded in the automobile, it is possible to realize a simple 
navigation system for knowing the distance of the automobile from the 
start position on the basis of the present position of the automobile. 
As described above, in this embodiment, when the owner of an automobile 
desires to know the present position of the automobile, the direction and 
approximate distance of the automobile from the position of the owner of 
the automobile (the position of the operation unit 1) can be displayed on 
the display 6 on the basis of the displacement information output from the 
displacement sensor 4 in the operation unit 1 and the absolute direction 
signal output from the absolute direction sensor 2. Thus, the owner can 
immediately know the present position of the automobile without walking 
for searching for the position where the automobile is parked. 
In this embodiment, it is sufficient to provide only the operation unit 1 
on the side of the sensed object, for example, on the automobile side, 
without providing any searching device, thereby simplifying the entire 
structure of the apparatus for searching for the sensed object, and the 
structure of the operation unit 1. 
Since the embodiment uses a displacement sensing member such as an 
acceleration sensor or the like as the displacement sensor 4 of the 
operation unit 1, displacement information can be generated without the 
movement of the operation unit 1 by the owner of the automobile. 
The embodiment shown in FIG. 2 permits the constant supply of a stable 
operating voltage to the operation unit 1 from the battery power source of 
an automobile even if no battery power source is provided on the operation 
unit 1. 
In the embodiment shown in FIG. 2, the removal sensor 3 comprises a switch 
for turning on and off the connection between the battery terminal 13a and 
the battery charger 51 of the automobile, and the removal sensing signal 
is generated by switching the switch. 
Although the above embodiment relates to a case where the sensed object is 
an automobile, the sensed object in accordance with the present invention 
is not limited to the automobile. The present invention can, of course, be 
applied to any other similar objects which are movable like an automobile. 
As described above, the present invention permits the display of the 
direction and approximate distance of a sensed object, e.g., an 
automobile, from the position of a person, e.g., the owner of the 
automobile, having the portable operation unit 1, on the basis of the 
displacement information output from the displacement sensor 4 in the 
operation unit and the absolute direction signal output from the absolute 
direction sensor 2, for example, when the owner desires to know the 
position of the automobile. The invention thus has the effect that the 
person having the operation unit 1 (the owner of the automobile) can 
immediately know the position of the sensed object (the position where the 
automobile is parked) by simply seeing the contents displayed on the 
display element 6 without walking about for searching for the sensed 
object. 
The present invention also makes the portable operation unit 1 enough for 
the apparatus for searching for the sensed object without any other 
searching units provided on the side of the sensed object, for example, 
the automobile side. The present invention thus has the effect of 
simplifying the entire structure of the apparatus for searching for the 
sensed object and the structure of the operation unit 1.