WO1991006938A1 - Cursor controller - Google Patents

Abstract

A miniature controller (11) is described for moving a cursor of the like on a computer display. The controller preferably is embodied as a key in a standard keyboard (12). It includes an actuation key (14) which is slidably mounted on an immovable base structure (13) which can be mounted on a printed circuit board (16) within the keyboard to project above the keyboard surface. Its construction is such that it accurately and reliably senses all motion of the key (14) and converts the same to a desired electrical signal for controlling motion of a cursor.

Description

CDRSOR CONTROLLER

DISCLOSURE

Background of the Invention

The present invention relates to controllers for producing electrical signals indicative of desired movements, for example, of a display cursor and, more particularly, to a miniature controller, its construction, electronics and methods of operation incorporated therein.

Controllers are now available for converting mechanical motion to electrical signals indicative of desired movements. Such controllers are used for many purposes. The rise in popular use of computers and work stations has resulted in numerous designs to control movement of a visible cursor or the like.

Some controllers are analog, i.e., produce an electronic signal which is proportional to all detectable mechanical motion over a continuous range. Joystick type controllers exemplifying analog devices can be found in U.S. Patent Nos. 4,607,159 issued August 19, 1986; 4,686,361 issued August 11, 1987; and 4,731,530 issued March 15, 1988. U.S. Patent No. 4,748,323 issued May 31, 1988 discloses a joystick controller which converts changes in a like path to generate a digital signal so as to have an "on" and an "off" state which can be detected. An audio loud speaker balance controller which is analog is described in U.S. Patent No. 3,811,047 issued May 14, 1974. Many computer display controllers utilize optoelectronic sensors to detect motion and convert it into electrical signals for controlling movement. For example, optoelectronic mice sense motion of the device itself via an optoelectronic sensing arrangement and convert it into signals for controlling the direction and/or rate of movement of a cursor on a computer terminal or work station screen. Most optoelectronic mice are also digital. In general, such digital optoelectronic mice are relatively bulky. Moreover, it is movement of the mouse itself over a surface that is detected. A clear surface area for such movement is therefore required for proper operation. (Special pads to provide such a surface area are available.) Another major problem with past optoelectronic controllers has been power consumption. This has inhibited the use of optoelectronic mice and other optoelectronic controllers in situations in which the controller is battery powered, e.g., with lap-top or portable computers. U.S. Patent No. 3,541,541 issued November 17, 1970 is directed to one of the early versions of such a mouse. A more common design for such an optoelectronic mouse at the time this patent application is being filed can be found in U.S. Patent No. 4,464,652 issued August 7, 1984. Other optoelectronic controllers are illustrated and described in U.S. Patent No. 4,284,885 issued

August 18, 1981; U.S. Patent No. 4,533,827 issued August 6, 1985; and U.S. Patent No. 4,284,885 issued August 18, 1981.

Efforts have been made in the past to provide controllers which are small, e.g., small enough to be finger actuated. Patent Nos. 4,459,578 issued June 10, 1984; 4,654,647 issued March 31, 1987; 4,680,577 issued July 14, 1987; 4,687,200 issued August 18, 1987; 4,692,756 issued September 2, 1987; and 4,739,128 issued April 19, 1988, all describe small controllers or finger actuated devices for moving cursors or the like. These have not been commercially accepted, primarily because they are bulky, complicated, unreliable, and/or do not provide the precision of control that is desirable. For example, U.S. Patent No. 4,680,577 describes a key switch in which movement of the key laterally is described as controlling the motion of a cursor. The design of the same, though, will result in quite unreliable operation. That is, slight lateral movements of the key may not be accurately detected. It will be recognized that this is a significant problem in key designs in which even the slightest movement has to move a cursor quite precisely. Moreover, such arrangement relies on strain gauges as motion sensing means. Strain gauges not only are expensive, but can be quite unreliable, e.g., they often can be overstressed.

One other problem which has plagued efforts to make controllers smaller is that it generally is necessary not only to precisely sense movement of an actuation key laterally, but also in a direction which is perpendicular to the plane of lateral motion for, for example, indicating a time of input. It will be recognized that in order for a design to be commercially viable, it must take into consideration the necessity of such dual usage of a key without hindering its precision.

Summary of the Invention

The present invention relates to a controller which is quite small in nature, i.e., it converts relatively small mechanical movements into an electrical signal which is indicative of desired control movement, and yet provides precise cursor control. It has many features which are responsible for the desired miniaturization and control precision.

For one, it is a combination of several different proven technologies. It measures minute mechanical motion in a precise, analog fashion and converts such analog measurement to a digital electrical signal to be easily processed by digital logic. For another, it is designed to assure that even the slightest movement by a manipulator is sensed and precisely transmitted to motion sensing means. In this connection, the manner in which this is achieved is so precise that the invention is incorporatable into a standard keyboard as a key.

An actuation key for manipulation is provided, having a stem for transmitting motion to a sensor. In keeping with an aspect of the invention, a rigidity guide is provided circumscribing the stem to insure that all motion of the actuation key in its plane indicative of a positional change, is transmitted to the sensor. Most desirably, the rigidity guide is slidably mounted to move with the stem and insure that irrespective of its location within its limited range of movement, its motion is accurately transmitted to the sensor. In accordance with another aspect of the invention, an intermediary tab is provided between the stem and a button switch to assure that depression or the like of the key, i.e., movement of the same in a direction normal to the plane of its movement to indicate a positional change, will accurately cause actuation of a button switch irrespective of the location of such stem within its limited range of movement in such plane. As another feature of the instant invention, it relies on optoelectronic sensing to detect mechanical motion. It does so, though, in an analog fashion. In this connection, although the previously mentioned U.S. Patent No. 4,748,323 discloses the use of optoelectronic sensing in a digital arrangement on intersecting axes, it does not suggest to one skilled in the field that one could obtain the precision associated with linear (analog) tracking with such an arrangement, much less obtain the greater controller sensitivity associated with linear tracking and yet still obtain the advantages associated with processing digital signals as will be discussed below.

Each optoelectronic sensor of the controller includes not only a detector but also a source of detectable energy, such as optical radiant energy produced by a light emitting diode (LED) . Thus, the total amount of energy which should be detected by each detector is known with precision. Precision is particularly important in an analog detection arrangement since it is variations in the amount of such energy that are used to determine a desired direction and/or rate of movement. (It will be appreciated that the precision of such a device can be adversely affected to a marked degree if the amount of radiation received by a detector may have uncontrolled variations.) In keeping with the invention, the analog measurement which is made is converted to a digital representation of the same with a simplified conversion technique. This technique enables one to obtain a digital representation of the analog signal with any desired precision. Moreover, this representation is a binary-coded digital number.

The mechanical aspects of the controller of the invention make the same ideal for miniaturization and incorporation into a keyboard. It includes a two- part base, one part of which is designed to be immovably mounted on a printed circuit board or similar carrier of electrical circuitry, while the other part is the motion sensor.

The invention includes many features and advantages when it is compared with what is known. Such features and advantages will be described in more detail in connection with the following description of a preferred embodiment thereof.

Brief Description of the Drawings

With reference to the accompanying nine sheets of drawing:

FIG. 1 is an isometric view of portions of a computer terminal and keyboard showing an implementation of a preferred embodiment of the invention;

FIG. 2 is an enlarged isometric view illustrating the preferred embodiment of FIG. 1;

FIG. 3 is an enlarged sectional view illustrating the manner in which the preferred embodiment of FIG. 1 is incorporated into the illustrated key board; FIG. 4 is an enlarged sectional elevation view of the mechanical aspects of the preferred embodiment;

FIG. 5 is an enlarged, exploded, isometric view of the mechanical aspects of the preferred embodiment implementation of FIG. 1;

FIG. 6 is an enlarged sectional view similar to FIG. 4 of the mechanical aspects of the preferred embodiment showing an alternate position thereof;

FIG. 7 is another enlarged sectional view similar to FIG. 4 of the mechanical aspects of the preferred embodiment, showing a third position;

FIGS. 8, 9 and 10 are partial sectional plan views illustrating differing positions of the sensing means of the preferred embodiment;

FIG. 11 is a general schematic view of an electronic circuit of the preferred embodiment;

FIG. 12 is a flow chart of a portion of a computer program of the preferred embodiment of the instant invention;

FIG. 13 is a flow chart of another portion of such computer program; and

FIGS. 14A through 14D are timing diagrams presented to facilitate an understanding of the invention.

Detailed Description of the Preferred Embodiment

Reference is first made to FIGS. 1 through 3 which show a preferred embodiment of a controller of the instant invention and its relationship to a computer terminal. FIG. 1 illustrates the same incorporated into a standard computer keyboard 12. In one implementation of the invention, the controller embodiment illustrated was .740 inches on a side at its largest dimension by .610 inches tall. The controller of the invention generally is the same size as a standard alphanumeric key in a keyboard. In this connection, the external mechanical aspect of the controller is made up of two components, a stationary base structure designed to be mounted immovably within a key board and a movable actuator key. With reference to FIG. 2, the portion of the controller designed to project from a keyboard has tapered sides divided laterally into layers. The lower two layers are a portion of the integral base structure, referred to by the reference numeral 13. The upper two layers define the exterior aspects of an actuator key 14 of the preferred embodiment, slidably mounted on the base structure. As illustrated in FIGS. 2 and 3, the base structure of the invention includes fastening means for securing the controller to a printed circuit board 16 within the interior of the keyboard 12. To this end, it includes projections 17 at its corners configured for force fit mating with corresponding apertures within such printed circuit board. It will be recognized that other fastening means could be provided. For example, the projections and cooperating apertures could be provided for a snap fit, the unit could be heat staked or (with large internal corner supports) the unit could be designed to be screwed into position.

The construction of the mechanical aspects of the controller of the invention is illustrated in some detail in FIGS. 4, 5, 6 and 7. With reference to such figures, it will be seen that the external portion of the actuator key of the controller has a shape optimizing manipulation. The center of the same is "cupped" as denoted by the reference numeral 18 to provide a finger contact area. The actuator key also includes a stem 19 provided to transmit motion of the manipulator portion of the key to sensing means and a button switch which will be described hereinafter. It is important, as mentioned previously, that all motion of the actuator key provided by a manipulator indicative of positional change be precisely and accurately transmitted to the sensing means. It is also important that any such motion of a manipulator's finger or the like desired to effect motion of a cursor result in corresponding motion of the key. To these ends, the controller includes a relatively complex internal structure, including structure defining a rigidity guide circumscribing the stem 19 to insure that all lateral motion of the actuation key within its limited range of motion is transmitted to the sensing means. It further includes structure to assure that depression of the same will cause corresponding depression of a button' switch as will be described irrespective of the lateral location of such key.

In more detail, the cup 18 is provided within a main manipulation portion 21 of the key 14 from which the stem component 19 depends. The actuation key is mounted rigidly to a slide 22. Such slide includes a cylindrical cup 23 which abuts against and supports the internal side walls of the manipulation portion 21 of the key, and a downwardly projecting hollow sleeve 24 within which the stem 19 fits as illustrated. The controller construction further includes a washer 25 of a tetrafluoroethylene fluorocarbon polymer (often sold under the trademark "Teflon") to facilitate sliding motion of the slide and, hence, the actuation key relative to other components of the controller as will be described.

The structure also includes a keeper 26 which cooperates with the slide to define the rigidity guide for the key stem mentioned above. As illustrated, such keeper includes not only a rectangular housing 27 for the key stem 19 and the slide sleeve 24, but also a guide flange 28. Four snaps 29 project inwardly of the housing for engagement within corresponding slots 30 in the slide sleeve 24.

A cover 31 is provided defining not only the external surface of one of the immovable base layers as illustrated but also a ledge 32 which is sandwiched between the cup 23 of the slide and guide flange 28 of the keeper. The cover further includes four legs 33 which provide a snap fit in a base housing described in more detail below.

The sensing means includes four pair 34 of optoelectronic sensors arranged on two intersecting orthogonal axes (the X and Y axes) Each pair is made up of a post mounted light emitting diode 35 and a post mounted phototransistor 36 positioned to receive optical energy from its associated LED. Such sensing means also includes a pair of shutters 37 and 38 designed to interact with the stem 21 and its rigidity guide for movement along orthogonal axes to control the amount of detectable energy transmitted between a respective one of the sources and its associated detector. The upper one of the shutters, shutter 37, has a pair of shutter blades 39 for travel between opposite ones of the optoelectronic pairs. Moreover, it includes a rectangular aperture 40 through which the stem 19 and its rigidity guide defined by the sleeve 24 and housing 27 project. Such aperture is dimensioned to provide a close fit between the rigidity guide and the shutter in the opposed directions of desired movement of the shutter blades, whereas the dimensions are sufficiently large in the orthogonal directions as illustrated in FIG. 4 to accommodate movement of the stem/rigidity guide combination in the orthogonal directions without corresponding movement of the shutters. The lower guide 38 also includes depending shutters 41 to interact with the two optoelectronic pairs that are orthogonal to those with which the blades 39 interact. (As illustrated in FIG. 5, there are two of the blades 41 parallel to one another on each side of the shutter 38 to provide symmetry for assembly.) Shutter 38 also includes an aperture 42 which is orthogonally dimensioned relative to the aperture 40. The lower shutter 38 also includes a pair of supporting and sliding ledges 43 on which the upper shutter 37 slidably rests as illustrated.

Pairs 44 and 45 of springs are provided which cooperate with the shutters 37 and 38, respectively, to urge the stem/rigidity guide and, hence, actuation key to its central "home" position. That is, the underneath side of the cover 31 includes slots (not shown) for capturing the ends of the springs of each respective pair. The center of each of the springs bears against a corresponding projection 55 on its associated shutter. This construction results in the springs urging the shutters and, hence, the stem/rigidity guide and actuation key to the central or home position.

A base housing 46 is provided from which the posts 17 project and which also houses the shutters and the sensing means. In this connection, the sensing means are physically connected to the printed circuit board 16 as illustrated, but project into the interior of such base housing. Such base housing includes inwardly projecting guides 47 which support and guide movement of the lower shutter 38. In accordance with an aspect of the invention, it also includes an inwardly projecting tab 48 which acts as an intermediary between the stem/rigidity guide and a button switch 49 adapted to respond to depression of the actuator. In this connection the upper side of intermediate tab 48 is engaged by the stem 19, and a projecting knob 50 is included on the opposed underneath side of such tab to contact switch 49. FIG. 6 differs from FIG. 4 in illustrating the state of the button switch. As shown, button 49 is illustrated in FIG. 4 in a convex, unactuated condition, whereas in FIG. 6 it is illustrated in a concave actuated condition.

FIG. 7 illustrates the interaction between the button and the tab 48 upon movement of the actuator stem to one of its extreme positions. Such stem engages the upper side of the tab 48 while the knob 50 still engages the button switch centrally. It will be seen that with this construction any depression of the actuation key 14 and, hence, stem 19 will result in knob 50 correspondingly depressing button switch 49, irrespective of whether the key is centered (FIG. 4) or is in one of its extreme positions (FIG .7) .

It will be seen from the above that a portion of the structure extends within the base and is slidably received therein for movement with the actuator. In this connection, it should be noted that the actuator key stem and its rigidity guide extend into the base structure for interaction with the optoelectronic sensor arrangement and the button switch.

FIGS. 8 through 10 are generally schematic views indicating the interaction of the shutter blades with the optoelectronic pairs. It first will be noted that while the optoelectronic pairs 34 are on opposite sides of the intersection of orthogonal axes (such axes are represented in FIG. 8 at 51 and 52) , the geometrical relationship is not symmetrical. This lack of symmetry is caused by geometrical constraints. It is for this reason that two sets of shutter blades 41 depend from the body of shutter 38. Each of the shutter blades 39 and 41 is opaque to the optical electromagnetic radiation which is emitted from its associated LED source. Thus, movement of each between the LED and phototransistor associated therewith will result in blockage of detectable energy therebetween.

FIGS. 8 and 9 illustrate movement of the upper one (as viewed in the figures) of the shutter blades 39 between its extreme positions, i.e., a position enabling all of the energy emitted by the LED to be received by the photodetector and a position blocking receipt of all energy which is so emitted by such detector. This can be seen by comparing the two figures. There are two other points which should be noted. For one, while the blade 39' for the lower one of the optoelectric sensors also will be moved, its movement will not in. any way change the amount of optical energy which flows between the LED source and detector associated therewith. That is, as can be seen from FIG. 9 while it follows the upper shutter blade because both blades are part of the same shutter structure, its direction of movement is such that its relationship with the energy flow provided by its optoelectronic sensor does not change.

Another point that should be noted is that the construction is such that moving of the shutter structure with the blades 39 as illustrated does not also cause movement of the blades 41. This is because of the orthogonal relationship of the apertures 40 and 41 discussed previously.

Comparison of FIGS. 9 and 10 illustrate corresponding movement of the shutter blade 41 (and its shadow blade) between the two extreme positions in which energy flow between the LED and phototransistor of its associated optoelectronic sensor is blocked (FIG. 10) and is allowed to flow (FIG. 9) . Again, the shutter blade on the opposite side of the axis is moved correspondingly, but does not change the flow of detectable energy between its associated LED and phototransistor.

The controller of the invention does not simply detect a motion which would place a shutter blade in its extreme positions, i.e., in "on" and "off" positions. It enables a continuous range of the shutter motion to be detected. That is, it has been found that the construction is sufficiently sensitive to enable one to detect the amount of optical energy allowed by a shutter to be transmitted between each LED and phototransistor. Thus, as long as the output of an LED remains constant or changes in a known way, an analog indication of movement is provided to assure accuracy of detection.

FIG. 11 is a general schematic view of the electronic circuitry of the preferred embodiment of the invention. With reference to such figure, the four infrared light emitting diodes are represented at 61-64. The anode of each diode is connected through an appropriate resistance 66 to a positive voltage source, represented as +V. This voltage can be provided, for example, by the host device to which the movement signals are to be directed. The cathode of each of the LEDs is connected, as is illustrated, to a controlling microprocessor 67 which will be described in more detail below.

One feature of the instant invention is that it reduces power consumption. That is, while in many conventional arrangements the source or sources of optical energy, e.g., light emitting diodes (LEDs), are energized continuously while a measurement of location or other movement is being made, the instant invention pulses these sources only when the measurement is being made for the particular parameter (e.g., axis change) for which the sensor is provided. The result is a lower current consumption duty cycle and, hence, low power consumption.

The four detectors associated respectively with each of the LEDs are represented in FIG. 11 at 68-72. As illustrated, each of these detectors is a phototransistor which exhibits a collector current that varies with the intensity of the optical energy which falls on such base. The emitter of each phototransistor is connected to ground as shown at 73, whereas the collector thereof is connected through an appropriate resistor 74 to a source of positive voltage. The amount of voltage drop' at any time across each of the resistors due to current flowing through the associated respective phototransistors will appear at the nodes 75-78, respectively. These nodes are also coupled, as illustrated, to respective input terminals of microprocessor 67.

Microprocessor 67 compares the voltages on the nodes 75-78 with reference voltages. This comparison is represented schematically in FIG. 8 by the showing of a connection 79 extending from each of the nodes 75-78 to a respective positive terminal of a comparator. The comparators are referred to by the reference numerals 80-83, and their respective negative terminals 84-88 are shown connected to a reference voltage line 99.

The voltage at each of the nodes 75-78 will be representative of the amount of optical energy received at each of the phototransistors. In this connection, each of such voltages typically will fall within a continuous range of voltage values. In keeping with the invention, this analog voltage is compared to a plurality of different potential voltage values in such continuous range, and a digital signal is produced representative of its value. This signal is a signed, two's compliment digital number. To this end, a resistor ladder, generally indicated by the reference numeral 91, is included to provide different comparison voltages. These comparison voltages appear on line 89 and are applied thereby to the negative terminals of the comparators 80-83.

The individual legs of ladder 91 are connected to energization output terminals of microprocessor 67, as represented at 92-96. Software controls sequential energization, via the legs of the resistor ladder 91, of differing voltages for comparison by the respective comparators 80-83 with the phototransistor outputs. Such phototransistors also will be turned on in a consecutive manner by the software as will become apparent below.

The relatively simple analog to digital conversion provided by the invention is most easily understood in connection with a description of an example, relative to radiation detected by one of the phototransistors. As mentioned previously, the voltage output of each of the phototransistors may be any voltage within a continuous voltage range. When photodiode 62 is turned on, for example, the voltage at 76 will indicate whether or not the shutter associated with the optoelectronic pair represented by LED 62 and phototransistor 69 is preventing any or all of such radiation from reaching the base of such transistor. That is, this voltage at 76 will be directly proportional to the amount of optical radiation permitted by the shutter to pass between the LED 62 and phototransistor 69. It will be compared with different voltage levels determined by the resistor ladder 91. To this end, output line 92 will first be energized to provide a comparison of the voltage drop across resistor 97. This voltage represents a preselected segment of the full continuous range within which the voltage at line 76 could lie. (Such segment typically will be one- half of the full continuous range.) The output of comparator 81 will be a digital output indicating whether or not such voltage falls within the selected segment. That is, it will determine the setting of the most significant bit of a 4-bit binary number. The second bit is set by energizing line 93. The result of such energization is that the voltage at node 76 will be compared to the voltage determined by resistors 97, 98 and 99. The value of such resistors is selected so that the voltage determined by the same represents a preselected portion of the segment represented by the voltage drop across the single resistor 97. This portion most desirably is approximately one-half of the segment represented by the voltage drop across resistor 97, i.e., one-fourth of the full range.

The third bit of the 4-bit binary number is set by energizing line 94. The result is that the comparison voltage will be defined by resistors 97, 98, 99, 101, and 102. Their values are most desirably selected so that the comparison voltage will be one half of the preselected portion, or one- eighth of the full range. The least significant bit is set by energization of line 96 to provide a finer resolution by determining if the analog voltage falls within a smaller segment of the subpart represented by the third bit. The values of resistors 103 are selected to provide the reference voltage with a value to enable such finer resolution to be obtained. The comparators 80-83 will thus sequentially generate the individual bit values of a binary number as a series of digital signals.

Operation of the resistor ladder will become clearer when the software illustrated in FIG. 13 and the timing diagrams of FIG. 14 are taken into consideration.

The total power consumption of the device is a function of several factors, most notably LED on time. Minimization of on-time therefore results in minimum power consumption (other circuit elements consume negligible amounts of current) Since most comparators require a significant settling time (and with the instant arrangement that could be a significant fraction of the total LED on-time during the conversion process) the present invention uses that otherwise wasted time segment (measured in microseconds) in processing the comparator input in parallel. That is, each bit is assumed to be in, and placed in, a particular state before the comparison and it then is tested for bit status as discussed above. This results in a pipelined operation, providing minimum conversion times, minimum LED on- time and, hence, minimum power consumption.

It will be appreciated that the resolution of the analog to digital conversion represented by the above is dependent upon the number of legs in the resistor ladder. That is, more legs can be provided if increased resolution is desired or fewer legs will provide decreased resolution. It will be necessary if a different number of legs are provided to arrange for a different number of comparisons to develop another size of binary number.

Communication to and from the host computer with the microprocessor 67 is represented by lines 100 and 110, respectively. Such communication to the microprocessor includes communication as to the state of the button provided by the input key at any given time. As will be discussed below, such state is checked. If the button is depressed, then the bit numbers which have been generated, if any, are read out. A commercially available microprocessor capable of implementing the invention is the microprocessor μPD7556 available from NEC Electronics, Inc.

FIGS. 12 and 13 are flow charts of software for the invention. FIG. 12 is an overall top level algorithm. The system operates intermittently at regular intervals in order to reduce power consumption. It starts off in a halted or power-down state. This is represented in FIG. 12 by block 111. Operation can be initiated by either of two sources, an external source or an internal source. The host computer can initiate such operation as the external source by interrupting the halt mode. This interruption, represented in FIG.12 by line 112, is a result of a logic state change occurring on line 100 of FIG. 11. In this particular embodiment, the quiescent state of line 100 is high (logic 1) and it is forced low (logic 0) by the host microprocessor. This triggers or otherwise automatically initiates an external interrupt event. It is also initiated on a periodic basis internally by the timing out of a system interrupt timer. This is represented by line 113 extending from box 114 labeled reset timer. In this connection, at the end of each operation, the timer is reset. In one implementation, it is configured to be reset to initiate operation every 5 milliseconds by interrupting the halt state. The operation itself consumes approximately 2.5 milliseconds. Thus, the system is not operating about one-half of the time.

The first operation that is performed during code execution is a determination of the source of the interrupt from the halt mode. This is represented by the decision block 116 labeled communication interrupt. If the interrupt was caused by an external communication via line 112, for example, the serial command received from the external source is inputted by a subroutine, as represented by block

117. The command byte is then tested for communication and transmission errors. Checking for a transmission error is represented by decision block

118. If it is determined that there is a transmission error, a resend command as represented by block _^19 is sent to the external source responsible for the erroneous command.

It should be noted that it is preferred that software be included to detect when consecutive communications from the external source have a transmission error. A different resend code is sent to the source to enable the system code designer to- react appropriately.

If there is no transmission error, a decision is made as to whether or not the command is one of the valid commands that the system is designed to execute. This operation is represented by process block 120. If it is not a valid command, a resend signal is again sent as is represented by the line 121. If it is a valid command, the function defined by such command is executed. This is represented by process block 122. Moreover, other potential interrupts are cleared and the timer is reset as is represented by block 123 to provide for an automatic interrupt from the halt mode upon the timer subsequently overflowing.

If the mechanism responsible for the interrupt from the halt mode is internally generated, i.e., because of the timer overflowing, the controller optical channels will be scanned. This is represented in FIG. 12 by process block 124. Execution of such scanning is represented by the flow chart of FIG. 13 and will be described in detail below. A decision is then made whether or not any of the channels indicate a manipulation. This is represented by decision block 125. If manipulation is detected, an activity flag in the code is appropriately changed if necessary, to be set as is represented by block 126. (As illustrated, if it is determined that there are no directional manipulations, the activity flag is not set.)

It is then determined whether or not there has been a button state change, i.e., whether the button has gone from a released to a pressed condition, or vice-versa. If there has been, the switch flags which indicate such a change are updated and the activity flag mentioned previously is set. This is represented by process blocks 127, 128 and 129. If there has been no button state change, the operations represented by process blocks 128 and 129 are skipped.

The activity flag is then checked to determine if it has been set. This is represented in FIG. 12 by decision block 130. If the activity flag has not been set, execution of the code is again returned to the halt or sleep mode as is represented by flow line 131. If the activity flag has been set, it is determined whether or not the number of scans is equal to the report rate. In this connection, in most implementations of the invention it is contemplated that there generally will be a higher number of scans than reports. That is, not each scan will be reported — unreported scans simply will cause internal updating. This operation is represented in FIG. 12 by decision block 132. If the number of scans does equal the report rate, execution of the code is placed in the halt mode. If the number of scans does equal the report rate, a packet of information defining the directional manipulation and button state change is transmitted to the host. Execution of the code is then terminated. Process blocks 133 and 134 represent such transmission and termination. As mentioned previously, block 123 in FIG. 12 represents scanning the optical channels. FIG. 13 is a flow chart of the program for such scanning. The scanning hardware is depicted in FIG. 11 described previously, and its description should be considered along with the following.

The first step in the scanning operation is to set the reference voltage on line 89 (FIG. 11) to one unit. This is represented in FIG. 13 by block 140. [It should be noted that the term "one" does not necessarily mean one volt. Rather, it means a full continuous voltage range that is selected. In a particular implementation of the instant invention in which a negative voltage change was used to record optoelectronic pair activity and five volts was used to indicate full blockage, it was set to .625 volts].

Once the reference test voltage is on, the optical channel to be tested is energized, i.e., the infrared light emitting diode and the phototransistor detector of such channel are energized. This is represented in FIG. 13 by block 141. Block 142 represents an initial time delay to allow the comparator to stabilize. The output of the comparator is then read as is indicated by block 143, and the channel is de- energized.

If the voltage being compared by the comparator with the reference voltage is equal to or greater than the latter, the comparator will be at its high state, i.e., a state representing a binary one. This decision making is represented by block 146. If the comparator output is not equal to one, the decision will be made as to whether or not all of the channels have been tested. This is represented at 147. If they have, the scanning operation is completed as represented by the "done" at 148. If it is not, the process is repeated for those channels which have not yet been tested. This is represented by flow line 149. The above operation is a "pretest" to again reduce power consumption. As mentioned previously, the most power consumptive items in the controller are the optical channels. This pretest allows one to minimize the amount of time the channel(s) needs to be energized in those instances in which clearly there is no activity.

It is necessary when a full comparison is made to compare the actual voltage on each of the nodes 75-78 for the respective channels 61-64, with the divisions of the continuous range of voltages (zero through the VREF) The instant invention thus converts an analog voltage directly to a binary number. In this particular implementation, the microprocessor is a 4- bit microprocessor and there are sixteen divisions of the reference voltage, resulting ink 4-bit binary number. If a comparator does indicate that a reference voltage is equal to or greater than the reference voltage, the first operation is a setting of the number of bits whose value is to be tested. This operation is represented in FIG. 13 by process block 150. The channel to be tested is then to be turned on as is represented by block 151, and comparisons are made with each of the resistor ladder legs. For each of such comparisons, the bit of the binary number (the comparison response) is assumed to be a one and, if it is not, it is changed. Process block 152 represents the presetting of the bit number, and blocks 153-156 represent the comparison. If the comparison indicates that the bit number should have been a zero rather than a one, it is changed as is represented by block 157. A determination then is made as to whether or not the comparison exceeds the maximum number of bits in the binary coded digital number. This is represented in the figure by blocks 158 and 159. If all of the bits of the four bit binary number have not been tested, the process is repeated, as is represented by the flow line 161. If they have all been tested, the channel that is being checked is de-energized as is represented by block 162. The reference voltage is then selected to be the change in x or Y values as is represented by block 163.

It is necessary that the above procedure be repeated for all the optical energy channels to be tested, in this case four channels. Decision block 164 represents making such determination. If all have not been tested, then the code is executed for the next channel as is represented by flow lines 166- 149. If all of the channels have been tested, the scanning operation is completed. This is represented by STOP block 167. The code then returns to the program represented by the flow chart of FIG. 12 for the remainder of the operation.

It is believed that consideration of timing diagrams will facilitate an understanding of the optoelectronic channel scanning and the generation of a four bit binary number when there is activity in a channel. FIG. 14 shows such timing diagrams. With reference to the same, the scanning and the voltage states at nodes 75-78 when there is no changes at the optoelectronic pairs is represented by FIG. 14A. This scanning is under the control of software as described above, and is continual. As illustrated, a voltage drop of 5 volts happens at each node when it is scanned if there is no activity at the optoelectronic pair that the same represents. The sequential nature of the scan operation also is apparent from FIG. 14A. That is, one can see that only one channel (a node) is ever active at any given time. The voltage at a node at any given time is representative of the state of the optoelectronic pair with which each is associated.

FIG. 14B illustrates the voltages at the nodes when of one of the optoelectronic pairs, i.e., that associated with node 76, is active. As illustrated, when the voltages at the other nodes, nodes 75, 77 and 78 are checked, there is a voltage drop from 5 volts to 0 volts. However, when the voltage at node 56 is checked, the voltage drop is less than 5 volts. This voltage drop is from 5 volts to approximately 1.75 volts. Because the scan indicated activity, the channel represented by node 76 is re-energized for the complete analog to digital conversion of the invention. Note that the test at nodes 77 and 78 are proportionately delayed due to the conversion represented at 76.

FIG. 14C is an enlarged view of the voltage at node 76. As illustrated, after the scanning test, the voltage is again reduced for the conversion.

FIG. 14D is a timing diagram illustrating the generation of a binary number indicative of the analog value. It illustrates the voltage at the negative input terminal 86 of the comparator 81 and, hence, the variations in the reference voltage to which the various voltages determined by the resistor combinations in ladder 91 are compared. The voltage output of the ladder is normally a nominal .3125 volts. This is indicated by the segment of the timing diagram in FIG. 14D labelled 174. The first activity during a test to develop a four bit binary number is to set the voltage reference to 2.5 volts, i.e., one-half of the total range. Thus, the most significant bit of the binary number is set at one, with the result that the binary number at the start of the testing is "1000". Segment 175 of the timing diagram represents such voltage. An assumption is then made that the voltage at node 93 is equal to or greater than the actual reference voltage, i.e., that the output of comparator 81 because of such assumption is a high state. This is represented in FIG. 14D by segment 176 of the timing diagram. Such segment represents a voltage of 3.75 volts, the addition of the 2.5 volts of segment 105 and 1.25 volts, the voltage change represented by the second bit in the four bit binary number. Thus, the four bit binary number is assumed at such stage to be "1100".

It is found by testing that the actual reference voltage determined at the node 92 is less than 2.5 volts. The most significant bit of the binary number is reset to zero, with the result that the binary number is "0100". The reference voltage is correspondingly decreased by 2.5 volts. This is represented by the drop in-voltage to 1.25 volts as indicated by segment 177.

The voltage into comparator 81 is then assumed to be greater than or equal to the reference voltage, i.e., that the binary number is "0110". The resulting voltage is 1.875 volts, the addition of

1.25 and .625 volts. This is represented in FIG. 14D by segment 178. When the input voltage is compared to the actual voltage, it is found that the input voltage of 1.75 is less than the 1.875 volts, with the result that the third bit of the four bit number is reset to zero.

The voltage representative of the least significant bit is assumed to be the high state, i.e., the binary bit number is assumed to be "0101". Then the assumption is tested by comparing the reference voltage for the last bit to the input voltage. It is found that the input voltage falls between the 1.875 volts and the 1.563 volts represented by the assumption. The lower value is selected, to provide a final voltage output representative of the binary number "0101". The voltage output representative of the resetting of the third bit as well as the assumption and testing for the fourth bit is represented in FIG. 14D by voltage segment 179.

This segment represents a voltage output of 1.563 volts, 1.875 volts minus .3125 volts.

Although the invention has been described in connection with preferred embodiments thereof, it will be appreciated by those skilled in the art that various changes and modifications can be made without departing from the spirit of such invention. For example, it will be appreciated that custom integrated circuitry could also be utilized to provide many of the functions required of the invention, as well as other functions which typically are included in controllers. Thus, the preceding description of a preferred embodiment is presented only to comply with the patent statutes. It is therefore intended that the coverage afforded applicants be limited by the claims and their equivalents.

Claims

CIAIMSWhat we claim is:

1. In a controller for producing an electrical signal indicative of a desired movement, the combination comprising: a. A source of detectable energy; b. Detecting means positioned to receive said detectable energy; c. A shutter which is opaque to said ♦ detectable energy mounted for continuous movement between a position blocking receipt by said detecting means of energy from said source and a position enabling said energy to be received by said detecting means whereby the amount of said detectable energy prevented thereby from being received by said detecting means varies Proportionately over a range; and d. Actuation means responsive to selected manipulation by moving said shutter continuously between said two positions.

2. The controller of claim 1 further including a base having fastening means for securing the same at a selected location.

3. The controller of claim 2 wherein said fastening means includes one or more projections configured to mate with corresponding apertures within a printed circuit board.

4. The controller of any of the previous claims wherein said desired movement is resolvable into components on two intersecting orthogonal axes; there are four of said sources of detectable energy individually positioned on associated sides of the intersection of said axes; there are four of said detecting means, each of which is positioned to receive said energy from only an associated one of said sources and produce an electrical signal proportional to the amount of said energy received thereby, each pair of detecting means and respective sources forming an optoelectronic sensor for an associated side of said axes' intersection; and there are four of said shutters, each of which is positioned for continuous movement between a position blocking receipt by an associated one of said detecting means of energy from its associated source and a position enabling said energy to be received by said detecting means.

5. The controller of claim 4 wherein said desired movement is within a limited range and said actuation means is responsive to selected manipulation in a direction normal to a plane containing said two intersecting orthogonal axes by generating an electrical signal indicative of said movement along said normal direction, said actuation means being adapted to respond to manipulation in said normal direction irrespective of the position of said actuation means within said limited range of movement in said plane.

6. The controller of claim 4 wherein said electrical signal is an analog signal and further including means for converting said analog electrical signal into a digital signal.

7. The controller of claim 6 wherein each of said detecting means produces an analog electrical signal over a continuous range of values proportional to the amount of said energy detected thereby, further including: a. Means for sensing said analog signal relative to said continuous range of values; b. Means for determining if said analog signal has a value falling within a preselected segment of said range; c. Means for determining if said value of said analog signal falls within a preselected portion of said segment; and d. Means for producing a digital signal indicative of whether or not the value of said analog signal falls within said preselected portion of said segment of said continuous value range.

8. In a controller for producing an electrical signal indicative of a desired movement in an accurate and reproducible manner, the combination comprising: a. sensing means for converting selected mechanical motion in a plane to an electrical signal indicating both the traveling distance and the direction of said mechanical motion in said plane; b. an actuation key movable in any direction in said plane and having at least two components, a first of which is designed to receive motion from a manipulator and the second of which is a stem to transmit motion of said first component to said sensing means; and c. a rigidity guide circumscribing said stem to insure that all motion of said first component in said plane is transmitted by said stem to said sensing means, whereby a manipulator is assured that any motion in said plane imparted to said first component will reliably cause said sensing means to produce an electrical signal indicative of said motion.

9. The controller of claim 8 further including a base enclosing said stem of said actuation key and said rigidity guide, said rigidity guide mounted slidably within said base for movement with said stem to insure that motion of said first component in said plane is transmitted to said sensing means irrespective of the location of said key in said plane.

10. The controller of claim 8 wherein said sensing means includes: a. a source of detectable energy; b. detecting means positioned to receive said detectable energy; and c. a shutter which is opaque to said detectable energy mounted for movement between a position blocking receipt by said detecting means of energy from said source in a position enabling said energy to be received by said detecting means.

11. The controller of claim 9 wherein said base also includes two components, a first of which includes means for mounting the same immovably to an electrical circuit carrier and a second of which is slidably mounted on said first base component and includes said first actuation key component exposed for said manipulation and said rigidity guide for said stem of said actuation key.

12. In a controller for producing an electrical signal indicative of a desired movement in an accurate and reproducible manner, the combination comprising: a. sensing means for converting selected mechanical motion in a limited range in a plane to an electrical signal indicating both the travel distance and the direction of said mechanical motion in said plane; b. a button switch for producing another electrical signal upon its manipulation in a direction normal to said plane; c. an actuation key movable both in any direction in said plane in said limited range and in a direction normal to said plane; and d. an intermediary member between said actuation key and said button switch for conveying movement of said actuation key in said direction normal to said plane to said button switch irrespective of the location of said actuation key in said limited range of said plane.

13. In a method of producing a digital signal indicative of a desired movement, the combination of the following steps: a. Sensing relative to a continuous range, an analog indication of said desired movement; b. Determining if an analog indication of desired movement falls within a preselected segment of said range; c. Determining if said analog indication of desired movement falls within a preselected portion of said segment if said indication does fall within said segment; and d. Producing a digital signal indicative of whether or not said analog indication of said desired movement falls within said preselected portion of said segment of said continuous range.

14. The method of claim 13 wherein said segment of said continuous range is about one half of said range, and said portion is about one half of said segment.

15. The method of claim 13 wherein said continuous range is a continuous range of values, and said analog indication is a value in such range.

16. The method of claim 13 further including the step of responding to said digital signal indicating that said analog indication does fall within said portion by determining if it falls into a subpart of said portion.

17. The method of claim 16 further including the step of responding to a determination that said analog indication falls within said subpart of said continuous range by determining if said analog signal falls within a preselected sub-segment of said subpart.

18. The method of claim 13 wherein said step of producing a digital signal includes producing a binary number indicative of whether or not said analog indication falls within said preselected portion.

19. The method of claim 18 wherein said binary number is produced by presuming individual binary digits thereof to be one of two values and thereafter testing to determine if said presumed value is correct.

20. The method of claim 13 wherein said step of sensing an analog indication of said desired movement includes using one of a plurality of optoelectronic sensors to develop an analog electrical signal indicative of said desired movement, said steps are sequentially repeated with all of said plurality of optoelectronic sensors, and further including the step of enabling the one of the optoelectronic sensors being used at any given time while maintaining the remaining optoelectronic sensors in a disabled state.

21. In a controller for producing a signal indicative of a desired movement, the combination comprising: a. A source of detectable energy; b. Detecting means positioned to receive said detectable energy and produce an analog electrical signal proportional over a continuous range to the amount of said energy that is detected at any given time; c. Means for varying continuously over said range, the amount of said energy which is detectable; d. An actuator for converting mechanical movement to control of said varying means; and e. Means for converting an analog signal representative of the detection of said energy over said continuous range into a digital electrical signal.

22. The controller of claim 21 wherein said source of detectable energy is a source of electromagnetic energy.

23. The controller of claim 21 wherein said source of detectable energy produces a generally constant amount of said energy, and said varying means changes the amount of said constant energy which is detectable.

24. The controller of claim 23 wherein said range is a continuous range of values, and said means for converting said analog electrical signal into a digital signal includes: a. Means for sensing said analog signal relative to said continuous range of values; b. Means for determining if said analog signal has a value falling within a preselected segment of said range; c. Means for determining if said value of said analog signal falls within a preselected portion of said segment; and d. Means for producing a digital signal indicative of whether or not the value of said analog signal falls within said preselected portion of said segment of said continuous value range.

25. In a controller for producing a signal indicative of a desired movement that can be resolved into components on two intersecting orthogonal axes, the combination comprising: a. Four sources of detectable energy individually positioned on associated sides of the intersection of said axes; b. Four detecting means, each of which is positioned to receive said energy from only an associated one of said sources and produce an electrical signal proportional to the amount of said energy received thereby, each pair of detecting means and respective sources forming an optoelectronic sensor positioned on an associated side of said axis intersection; c. Four shutters, each of which is positioned for movement to control the amount of detectable energy transmitted between an associated one of said sources to its associated detecting means; and d. Actuation means for controlling movement of said shutters to change the amount of said energy which is detected over a continuous range of values for said energy.

26. The controller of claim 25 wherein said actuator is coupled to said shutters to move only one of the same to a position changing the amount of said energy detected at one of said pairs without interfering with the transmission of detectable energy between the source and detector of any other of said pairs.

27. The controller of claim 25 wherein said four sources of detectible energy, said four detecting means and said four shutters provide sensing means for converting selected mechanical motion in a plane to an electrical signal indicating both the travel distance and direction of said mechanical motion in said plane; said actuation means includes an actuation key movable in any direction in said plane and having at least two components, a first of which is designed to receive motion in said plane from a manipulator and the second of which is a stem to transmit motion of said first component to said sensing means; further including a rigidity guide circumscribing said stem to insure that all motion of said first component in said plane in transmitted by said stem to said sensing means, whereby a manipulator is assured that any motion in said plane imparted to said first component will reliably cause the sensing means to produce an electrical signal indicative of said motion.