Controller apparatus using force sensing resistors

A controller apparatus for controlling a device comprising a support having a surface with a wall extending therefrom and along a segment of the surface. A plurality of force sensing members are positioned in a predetermined arrangement adjacent to an inner surface of the wall of the support with each member generating a signal in response to a force applied to the member. An assembly for adaptable engagement with the force sensing members is translationally movable to selectively engage and transmit a translational force to the force sensing members to develop a signal for control of a function of the device.

BACKGROUND OF THE INVENTION 
This invention relates to a controller apparatus, particularly, a 
controller apparatus for use with force sensing resistors in a 
surveillance assembly, computer-related or video game device or other 
device. 
Controllers have been used or implemented in a variety of devices and 
assemblies over the years, particularly, in surveillance assemblies, 
computer-related devices and video game assemblies. An example of a 
controller used for a surveillance assembly is disclosed in U.S. 
application Ser. No. 08/171,215 ("Paff, et al."). The controller of Paff 
et al. controls panning and tilting of a video surveillance camera by 
using a mechanical linkage assembly. The linkage assembly translates the 
movement of a user movable disc of the controller into signals which can 
be used to generate corresponding pan and tilt control signals for the 
surveillance camera. 
Other types of controllers, such as a mouse, joystick, trackball and 
control keys, have been employed to control cursor movement in a 
computer-related device or video game assembly. To control such cursor or 
object movement, many of these controllers utilize some type of force 
sensing means. 
U.S. Pat. No. 5,278,557 to Stokes, et al. ("Stokes, et al.") discloses one 
example of a cursor movement control key using force sensing resistors. 
The cursor movement control key has an external key cap engaging an 
actuator which bears against a force-sensing resistor upon depression and 
angular tilting of the external key cap. The force-sensing resistor has a 
junction resistance which varies inversely to the pressure applied thereto 
to control cursor movement. 
Force sensing resistors are devices sold by Interlink, Inc. of California. 
A force sensing resistor is a thin film polymer device which exhibits a 
decrease in resistance when an increase in force is applied normal to its 
surface. More specifically, a force sensing resistor comprises two flat, 
thin polymer layers. One layer has two interleaved conductors printed on 
its face. The other layer has a resistance semiconductor material printed 
on its face. The two layers are then laminated or spaced closely together 
relative to one another. A spacer adhesive is generally used to laminate 
the two layers. 
A force sensing resistor operates as follows. When no force is applied, an 
open circuit exists between the two layers. However, when a force is 
applied normal to the device, the two layers make contact to result in a 
closure across the two conductors through the resistive material. The 
conductance allowed is dependent upon the force applied and the area over 
which the force is applied. The resistance will change as a function of 
the force applied over a constant-sized area. Thus, a greater force 
results in a greater current flow between the conductors. 
While the controllers of the above-discussed patent and patent application 
enable control of a device or cursor movement, the controllers are 
complicated structures. In addition, each controller requires a number of 
tiny parts which increase the cost of production of the devices. 
Accordingly, other types of controllers of less complication and cost are 
being sought. 
It is, therefore, an object of the present invention to provide a 
controller apparatus with a simple construction. 
It is a further object of the present invention to provide a controller 
apparatus which has a small number of parts in its design. 
It is an additional object of the present invention to provide a controller 
apparatus which is economical to manufacture. 
SUMMARY OF THE INVENTION 
In accordance with the principles of the present invention, the above and 
other objectives are realized in a controller apparatus in which a 
plurality of force sensing members are arranged at predetermined positions 
adjacent to a wall which extends from and along a segment of the surface 
of a support. An assembly is provided which includes a translationally 
movable member which selectively engages and transmits a translational 
force to the force sensing members to thereby develop signals which can be 
used to control one or more functions of a device. 
In the embodiment of the invention to be disclosed hereinafter, the support 
of the controller apparatus comprises a cup and the translationally 
movable member comprises a cylindrically-shaped puck located within the 
cup. The puck has top and bottom puck surfaces, a side puck surface and a 
centrally located recess extending from the top puck surface toward the 
bottom puck surface. 
The force sensing members are situated between the side puck surface and 
the inner surface of the wall of the cup. A disk-like body is attached to 
the puck by a centrally located shaft which extends through a centrally 
located aperture of the disk-like body and is positioned in the centrally 
located recess of the puck. The centrally located shaft extends through 
the disk-like body and into a centrally located recess of a knob disposed 
on a top surface of the disk-like body.

DETAILED DESCRIPTION 
FIGS. 1-3 show various views of the controller apparatus 10 of the present 
invention. As shown, the controller apparatus 10 comprises a cup-shaped 
support 12 having a lower support surface 14 and a wall 16 which extends 
around the perimeter of the surface 14. A plurality of force sensing 
members or resistors 18a, 18b, 18c and 18d are positioned in a 
predetermined arrangement adjacent to an inner surface 20 of the wall 16. 
As illustrated, the force sensing resistors are in strip form and are 
equally spaced at 90.degree. intervals along the inner surface 20. More 
particularly, the force sensing resistors 18a-18d are centrally and 
symmetrically positioned about 0.degree., 90.degree., 180.degree. and 
270.degree. positions proximate to the inner surface 20 and each resistor 
is in bearing engagement with the inner surface when a translational force 
is applied thereto. 
Each force sensing resistor generates a signal which varies as a function 
of the amount of force applied to the resistor. As a result, by varying 
the applied translational force, a variable signal can be generated which 
can then be used to provide variable control of a function of a device. 
For example, if the function being controlled is speed, a light 
translational force or pressure on a force sensing resistor, will yield a 
low conductance, which can be translated into a slow speed control signal. 
A large translational force or pressure on a force sensing resistor, on 
the other hand, results in a higher conductance, which, can be translated 
into a fast speed control signal. 
An assembly 17 serves as a mechanism for selectively providing 
translational forces to the force sensing resistors 18a-18d. The assembly 
17 includes a first member or cylindrically-shaped puck 22. The puck 22 is 
supported by the cup 12 and is movably positioned within the region 24 
defined by the inner surface 20 of the wall 16, as clearly shown in FIG. 
3. The puck 22 has top, bottom and side surfaces 26, 28 and 30, 
respectively, and a centrally located recess 32 extending from the top 
puck surface 26 toward the bottom puck surface 28. The side surface 30 of 
the puck 22 is slightly rounded to allow for engagement with the force 
sensing resistors 18a-18d when a translational force is applied. The side 
surface 30, however, is not limited to the illustrated embodiment but may 
have a variety of configurations, e.g., contoured or pointed profiles for 
engagement with the force sensing resistors. 
The assembly 17 also includes a second member 34 attached to the puck 22 
for moving the puck 22 in response to a force being applied by a user's 
hand to the second member. As shown, the second member 34 has a first 
region or disk-like body 36 having top and bottom disk surfaces 38 and 39, 
respectively, and a centrally located aperture or hole 33. The centrally 
located aperture 33 extends through the disk-like body 36 from the top 
disk surface 38 to the bottom disk surface 39. A second region or knob or 
grip 44 of the member 34 is disposed on the top disk surface 38. The knob 
44 has top and bottom knob surfaces 40 and 41 and a centrally located 
recess 43 extending from the bottom knob surface 41 toward the top knob 
surface 40. A centrally located shaft 42 positioned in the recess 43 of 
the knob 44 extends through the aperture 33 of the disk-like body 36 and 
is positioned in the centrally located recess 32 of the puck 22. 
The shaft 42, which extends from the knob 44 into the recess 32 of the puck 
22, may be adapted to provide different feels for the user. Thus, a rigid 
material can be used for the shaft 42 to restrict travel of the knob 44. 
This provides a "stiff" or "hard" feel to the hand of a user. On the other 
hand, a pliable material can be used for the shaft 42. This allows greater 
knob movement and provides a "soft" or "spongy" feel to the user. 
As shown in FIGS. 2 and 3, the diameter of the disk-like body 36 extends 
beyond the width of the puck 22 and is of sufficient dimension to allow 
support of the palm of the user's hand. This arrangement reduces wrist 
fatigue of the user while using the controller apparatus 10. 
As shown in FIG. 2, each of the force sensing resistors 18a-18d has a front 
side 46 and a back side 48 with the back side 48 being proximate to the 
inner surface 20 of the wall 16 of the cup 12 and the front side 46 being 
proximate to the side surface 30 of the puck 22. Spacers or engaging pads 
50 are positioned between the side surface 30 of the puck 22 and the front 
sides 46 of the force sensing resistors. Each pad 50 comprises a 
compressible material such as a polyurethane foam. Based upon how the puck 
22 is fitted within the cup 12, a pre-loading force is applied to the 
respective force sensing resistor through the pad 50. 
Without a preloading force, each force sensing resistor has essentially an 
infinite resistance. Thus, if a small force is applied to a resistor, its 
resistance drastically drops, providing a response which is not easily 
controllable by the user. Therefore, by preloading each of the resistors 
18a-18d with a respective pad 50 more accurate control can be achieved. 
Also, by preloading each force sensing resistor, the device being 
controlled will exhibit a more linear response to translational forces 
being applied by the user. 
Buttons 52 and 54 are disposed on the knob 44 and provide signals for 
control of additional functions by the user depending on how the 
controller apparatus 10 is to be used. The buttons 52 and 54 may have a 
variety of forms and may also incorporate force sensing resistors for 
controlling the desired additional functions. The knob 44 may also be 
rotatable in relation to the disk-like body 36 to provide further control 
options for the controller apparatus 10. Also, the knob 44 and disk-like 
body 36 may rotate together or independently to accommodate various user 
positions. 
FIGS. 1 and 2 illustrate the controller apparatus 10 in a stand-alone 
application. The controller apparatus 10 may also be fixed or mounted to a 
surface (not shown) to provide greater stability and support for the 
apparatus 10. The controller apparatus 10 may also be incorporated into a 
housing or structure to control any type of device. For example, one 
particular type of device might be a surveillance assembly including a 
camera and lens assembly. Depending on the configuration of the controller 
apparatus 10, the signals generated by the force sensing resistors can be 
utilized for control of different functions of the camera and lens 
assembly. Such functions may include panning and tilting of the camera and 
lens assembly. This may be accomplished by employing a microcomputer 100 
to convert the generated signals into pan and tilt control signals, as 
shown in the block diagram in FIG. 5. 
In FIG. 5, the microcomputer 100 is responsive to signals from the force 
sensing resistors 18a-18d and from the buttons 52 and 54 of the controller 
apparatus 10. The microcomputer 100 is also responsive to signals from 
numeric and special function keys 88 and 90 of a keypad area 84. Based on 
these signals, the microcomputer 100 delivers appropriate control signals 
to the surveillance assembly 104 over a communications link 108. 
More particularly, the microcomputer 100 determines from its scanning 
operation of the signals generated by actuation of the buttons 52 and 54 
whether a function, such as focus, zoom or iris control, is to be changed. 
Also, depending upon the length of time of the signal, i.e., the length of 
time the respective button is pressed, the microcomputer 100 determines 
the speed of control for the function. 
Likewise, based on the signals from the force sensing resistors 18a-18d, 
the microcomputer 100 determines whether panning and tilting functions are 
to be changed and the speed of the function. For example, a slight 
translational movement of the assembly 17 to the right causes the force 
sensing resistor 18b to output an appropriate X axis displacement signal 
to the microcomputer 100. The microcomputer 100 then interprets the signal 
and generates a pan right control signal. Increased force from the 
assembly 17 to the right causes an increased output from the resistor 18b. 
The microcomputer 100 again interprets this signal and develops an 
increased speed pan right command for controlling the pan right function. 
FIG. 4 shows controller apparatus 10, keypad 84, and microcomputer 100 of 
FIG. 5 incorporated into a controller assembly 82. The assembly 82 houses 
the apparatus 10, keypad 84 and microcomputer 100 within a housing 80 
having a palm rest 86. The housing includes an upright portion for holding 
the plurality of numeric and special function keys 88 and 90 of the keypad 
84. The keys 88 and 90 can be used to control other functions of the 
surveillance assembly 104 and are symmetrical and preprogrammable for 
individual users based upon programs and data stored in a non-volatile 
memory 92 (see, FIG. 5) also included in the housing 80. 
As above-noted, buttons 52 and 54 of the controller apparatus 10 can be 
used to control zoom, focus or iris functions of the lens unit of the 
surveillance assembly 104. The pan and tilt functions of the camera unit, 
in turn, are controlled by the assembly 17 of the apparatus 10. 
FIG. 6 illustrates similar components as in FIG. 5 but shows a 
computer-related device or video game assembly 110 being controlled by the 
controller apparatus 10 and the keypad 84. In this case, the signals for 
the force sensing resistors of the apparatus 10 would be used to control 
the X axis and Y axis displacement of a cursor or object on a computer or 
video screen of the device 110. The signals for the force sensing 
resistors may also be used in a variety of applications, such as 
controlling line thickness or color saturation, on the computer or video 
screen of the device 110. 
The controller apparatus 10 of the present invention is not limited to the 
illustrated embodiments but may be any size or shape depending upon the 
requirements of the user. Thus, for example, the controller apparatus 10 
may take on different configurations to accommodate one or two-handed use, 
the type of device being controlled and the way in which the controller 
apparatus is implemented in relation to another apparatus. 
Also, the controller apparatus 10 is not confined to the support 12 being a 
cup-shaped configuration or utilizing four force sensing resistors. Other 
configurations dictated by the particular application and the needs of the 
user may also be developed. For example, a housing of an apparatus may be 
used to provide support for the assembly 17 and one or more force sensing 
resistors. In addition, the wall 16, rather than extending around the 
perimeter of the lower support surface 14, can also be an extension from 
the surface 14. 
In addition, the configuration of the recess 43 in the knob 44 allows the 
user to insert a variety of different types of solid or hollow shafts 
depending upon the desired type of "feel" the user prefers as well as 
permitting insertion of any wiring (not shown) for the buttons 52 and 54. 
The recess 43 may also extend the entire length of the knob 44 to allow 
the user to easily remove and replace the shaft. A movable top plate or 
portion (not shown) positioned on the knob may be used to conceal the 
recess 43. 
The puck 22, disk-like body 36, knob 44 and cup 12 of the controller 
apparatus 10 are, preferably, made of plastic and are rigid or semi-rigid 
in strength. This provides adequate structural support for the controller 
apparatus 10. In addition, the disk-like body 36, knob 44 and shaft 42 may 
be molded as a single part and in other cases may be formed of separate 
parts engaging one another. In the latter case, pins, grooves, adhesive or 
any other retaining or attaching means may be used to assemble and hold 
the components together and to maintain the structural integrity of the 
controller apparatus 10 during operation. 
The controller apparatus 10 may also be used in applications, other than 
the specific applications mentioned above. The controller apparatus 10 
may, in general, be used in applications where control of an electronic 
device is required. Particular applications, might be as a controller for 
a simulator-type apparatus or a machine-controlled robot. Other 
applications might be as a controller for devices for educational 
development, medical, rehabilitative or handicap-specific applications. 
In all cases it is understood that the above-described arrangements are 
merely illustrative of the many possible specific embodiments which 
represent applications of the present invention. Numerous and varied other 
configurations, can be readily devised in accordance with the principles 
of the present invention without departing from the spirit and scope of 
the invention.