US20200400519A1 - Piezoresistive sensors and sensor arrays - Google Patents

Abstract

Highly expressive and flexibly programmable foot-operated controllers are described. Specific implementations are intended for musical applications and allow musicians an unprecedented degree of control of a wide variety of musical components and subsystems for recording and/or performance.

Description

INCORPORATION BY REFERENCE
• An Application Data Sheet is filed concurrently with this specification as part of this application. Each application to which this application claims benefit or priority as identified in the concurrently filed Application Data Sheet is incorporated by reference herein in its entirety and for all purposes.
BACKGROUND
• The present invention relates to programmable controllers and, more particularly, to foot-operated controllers configured to control a wide variety of systems including, for example, musical components and subsystems in the context of recording and performance
• Almost all foot-operated effects switches employed by musicians to date have been large and heavy with limited displays, limited input capabilities, and limited control capabilities. These switches, which typically only have “on” and “off” states, are generally only capable of controlling a single effect. As a result, a musician needs one switch for each effect being controlled. Given the size and weight of these conventional switches, there are obvious and serious limitations to their effective use; particularly for musicians who travel a considerable amount, i.e., most musicians. This outdated technology also prevents artists from taking full advantage of the myriad electronic and software tools now available to musicians to push the boundaries of artistic expression.
SUMMARY
• According to the present invention, highly expressive and flexibly programmable controllers are provided. According to various embodiments, a controller includes a plurality of pressure-sensitive regions arranged on a substrate. Each pressure-sensitive region has one or more sensors associated therewith configured to generate one or more output signals that are monotonically representative of time-varying pressure applied to the one or more sensors via the associated pressure-sensitive region. A processor is configured to receive the one or more output signals from the one or more sensors associated with each pressure-sensitive region and generate control information in response thereto. The control information is for controlling operation of one or more processes or devices in communication with the controller.
• According to more specific embodiments, there are two or more sensors associated with each pressure-sensitive region, and the one or more output signals generated by the two or more sensors are also representative of one or more directions of the pressure applied to the pressure-sensitive region. According to an even more specific embodiment, the one or more directions are relative to a surface of the pressure-sensitive region and include a clockwise rotation, a counter-clockwise rotation, a first linear direction along a first axis, and a second linear direction along a second axis.
• According to specific embodiments, each of the sensors includes a piezo-resistive material having an electrical resistance which changes with the pressure.
• According to specific embodiments, at least some of the control information includes musical instrument digital interface (MIDI) messages, and the controller further includes a MIDI interface configured to facilitate communication of the MIDI messages from the processor to an external MIDI device.
• According to specific embodiments, the one or more processes or devices include a computing device on which a software application is running, and the control information is provided to the computing device for use by the software application.
• According to specific embodiments, the control information includes either or both of musical instrument digital interface (MIDI) messages or Ethernet messages.
• According to specific embodiments, the processor is programmable to save one or more groups of settings for each pressure-sensitive region corresponding to the control information for that pressure-sensitive region. According to still more specific embodiments, the processor is programmable to save groups of settings for each of the pressure-sensitive regions collectively as scenes. According to still more specific embodiments, the processor is programmable to save a sequence of scenes as a setlist.
• According to specific embodiments, the processor is programmable to configure sensitivity to the pressure for the one or more sensors associated with each pressure-sensitive region. According to more specific embodiments, the processor is programmable to configure sensitivity to the pressure for each of one or more directions of the pressure.
• According to specific embodiments, the controller includes navigation controls configured for selecting a functionality of each of the pressure-sensitive regions.
• According to various embodiments, computer-implemented methods and computer-program products are provided for configuring a controller having a plurality of pressure-sensitive regions configured to generate output signals that are monotonically representative of time-varying pressure applied to each of the pressure-sensitive regions. The output signals are also representative of one or more directions of the pressure applied to each of the pressure-sensitive regions. The controller also includes a processor configured to receive the output signals and generate control information in response thereto. According to these computer-implemented methods and computer-program products, the processor is programmed to configure sensitivity to the pressure for each of the one or more directions for each pressure-sensitive region. In addition, the control information corresponding to each of the pressure-sensitive regions is mapped to one or more destination processes or one or more destination devices thereby facilitating control of the destination processes or destination devices by the controller.
• According to more specific embodiments of such computer-implemented methods and computer-program products, the processor is programmed to save one or more groups of settings for each pressure-sensitive region corresponding to the control information for that pressure-sensitive region; to save a groups of settings for each of the pressure-sensitive regions collectively as scenes; and to save a sequence of scenes as a setlist.
• A further understanding of the nature and advantages of the present invention may be realized by reference to the remaining portions of the specification and the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 is a top view of a foot-operated controller designed in accordance with a specific embodiment of the invention.
• FIG. 2 is a block diagram illustrating components and operation of a foot-operated controller designed in accordance with a specific embodiment of the invention.
• FIG. 3 includes a cross-sectional view of a foot-operated controller designed in accordance with a specific embodiment of the invention.
• FIG. 4 includes a cross-sectional view of one sensor of one key of a foot-operated controller designed in accordance with a specific embodiment of the invention.
• FIG. 5 is a system diagram illustrating various musical components and sub-systems connected to a foot-operated controller designed in accordance with a specific embodiment of the invention.
• FIGS. 6-12 are examples of interfaces of a software application which may be used to configure and control operation of a foot-operated controller designed in accordance with a specific embodiment of the invention.
DETAILED DESCRIPTION
• Reference will now be made in detail to specific embodiments of the invention including the best modes contemplated by the inventors for carrying out the invention. Examples of these specific embodiments are illustrated in the accompanying drawings. While the invention is described in conjunction with these specific embodiments, it will be understood that it is not intended to limit the invention to the described embodiments. On the contrary, it is intended to cover alternatives, modifications, and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims. In the following description, specific details are set forth in order to provide a thorough understanding of the present invention. The present invention may be practiced without some or all of these specific details. In addition, well known features may not have been described in detail to avoid unnecessarily obscuring the invention.
• Embodiments of the present invention relate to configurable control systems that are lightweight, durable, and flexibly programmable for use in a wide variety of applications. A particular class of embodiments are implemented as foot-operated controllers. Still more specifically, embodiments will be described herein with reference to particular applications of such foot-operated controllers that are intended for use by musicians to control a wide variety of components and processes during recording and performance. However, it should be noted that the scope of the invention should not be limited by reference to such applications. To the contrary, embodiments of the present invention may be used in a wide variety of contexts to facilitate control of a wide range of processes, devices, and systems.
• A class of embodiments of the invention will now be described using the name SoftStep™ or SoftStep™ controller to refer to the foot-operated controllers. The SoftStep™ (a top view of which is shown inFIG. 1) is a lightweight, compact, and highly expressive foot-operated controller. The depictedimplementation100 of the SoftStep™ has aUSB port102 by which the SoftStep™ may be connected to an external computer, and through which power may be delivered to the SoftStep™. Anexpression port104 is provided for plugging in a volume or expression pedal. There is also anexpansion port106 for a musical instrument digital interface (MIDI) expander (described below) that enables use of the SoftStep™ without a computer to control, for example, a MIDI synthesizer and/or rack. According to some implementations, power can also be supplied through the expansion port. The SoftStep™ is provided with backlighting so that its controls can be seen well in low lighting situations, e.g., on stage. There is a 4-characteralphanumeric display108 that is user programmable. There are alsoLEDs110 for eachkey112 that can be programmed to display the user's choice of data. The depicted implementation of the SoftStep™ is rubberized and has a carbon-fiber back to give it strength and stability, although a wide variety of other materials are contemplated for various implementations.
• FIG. 2 is block diagram of a portion of a SoftStep™ implemented according to a specific embodiment of the invention. According to the depicted embodiment, four pressure sensors202 (e.g., piezo-resistive pads) are located underneath and in the corners of each numbered button orkey204 and provide a continuous range of input instead of just an “on” or “off” state. It will be understood that any of a variety of pressure sensors and pressure sensitive materials may be employed to implementsensors202. It will also be understood that a fewer or greater number of sensors may be employed to achieve some or all of the functionalities enabled by the configuration shown. For example, embodiments are contemplated in which three sensors are configured in a triangular arrangement. Embodiments using two sensors for each key pad, while likely to provide a lesser level of control, are also contemplated.
• A processor206 (Silicon Laboratories 8051F344) converts the sensor outputs to control commands for corresponding effects. It will be understood thatprocessor206 may be implemented using any of a wide variety of suitable devices known to those of skill in the art. The operation of particular implementations of the code that governs the operation ofprocessor206 may be understood with reference to the various embodiments described herein. Such code may be stored in physical memory or any suitable storage medium associated with the processor, as software or firmware, as understood by those of skill in the art. However, it should be noted that the use of a processor or similar device is not necessary to implement all aspects of the invention. That is, at least some of the functionality described herein may be implemented using alternative technologies without departing from the scope of the invention. For example, embodiments are contemplated which implement such functionalities using programmable or application specific logic devices, e.g., PLDs, FPGAs, ASICs, etc. Alternatively, analog circuits and components may be employed for some functionalities. These and other variations, as well as various combinations thereof, are within the knowledge of those of skill in the art, and are therefore within the scope of the present invention.
• According to some embodiments the multiple sensors (e.g., one in each corner of a particular button) enable the detection of motion, i.e., captured in the time-dependent pressure exerted on the different sensors. This allows, for example, the user to roll his foot clockwise or counter-clockwise to effect changes such as, for example, turning the volume or emphasis up or down for a particular channel or effect. Other motions, e.g., rocking back and forth or side to side, might also be captured by various sensor configurations contemplated by the present invention.
• In the embodiments depicted inFIGS. 1 and 2, the four corner piezo-resistive pads in each key are referred to as North West (NW), South West (SW), North East (NE), and South East (SE). As shown inFIG. 2, each key is responsive to 5 degrees of control: in the X-axis and Y-axis, clockwise (CW) rotation, counter-clockwise (CCW) rotation, and pressure (Z-axis). Four piezo-resistive pads (not shown) in the diamond-shaped navigation pad (Nav Pad)114 are referred to as North (N), South (S), East (E), and West (W). Each of the piezo-resistive pads in the SoftStep™ sends 7-12 bit data to the processor from which the sources are derived. As will be discussed in greater detail below, these control sources are mappable to any MIDI destination or Ethernet destination (e.g., open sound control (OSC)). Table 1 summarizes source derivation according to a particular embodiment of the invention.

• TABLE 1
  Sources	Derivation
  Pressure	Averages the total pressure of the piezos per key.
  Live	(NW + SW + NE + SE)/4 = Pressure Live. A variation for
  	seated use would take the largest of the 4 values = Pressure
  	Live.
  X Live, Y	Plots the relative location of pressure in the Cartesian plane.
  Live	When no pressure is applied to the key, coordinates are
  Polar	(64, 64). If all pressure is applied to NW piezo, coordinates
  (circular)	are (0, 127), NE (127, 127), SW (0, 0), SE (127, 0).
  	(SW − NW) = x, (SE − NE) = y;
  	Convert from Cartesian coordinates to polar where x is the
  	real input and y is the imaginary. Add 0.785398 to phase,
  	and convert back to polar coordinates, with additional
  	scaling.
  Pressure	Same as live parameters above, except when the user
  Latch, X	removes foot from key, the value remains. All live values
  Latch, Y	are, in addition, delayed in software to make latching
  Latch	possible.
  X Increment	If pressure is weighted negatively or positively along the X-
  	axis, add/subtract to the current value in proportion to the
  	weight's magnitude.
  Y Increment	Same as X Increment but measured along the Y-axis.
  Rotation	Assign a target value to each piezo. When the pressure on
  	one piezo exceeds the others, slew from the current value to
  	the value assigned to that particular piezo.
  Rotation Rel.	Same as Rotation above except that when the user initially
  	applies significant pressure to a key, rotation value
  	initializes to 63, and one navigates to a new value from
  	this starting point.
  Foot On	If the total pressure (derived from pressure live) exceeds a
  	designated threshold, then Foot On goes true.
  Foot Off	If the total pressured falls below a designated threshold, the
  	Foot Off goes true.
  Wait Trig	If a Foot On is detected, and remains true for a specified
  	duration, Wait Trig outputs the total pressure applied to that
  	key at the moment that duration has elapsed. After the
  	pressure value is ouput, Wait Trig returns to zero after
  	another specified duration.
  Fast Trig	Same as Wait Trig, with minimal delay.
  Dbl Trig	Same as Wait Trig, except Dbl Trig must detect a Foot On,
  	and Foot Off, and an additional Foot On (two Foot On
  	events) in a designated amount of time. Like a double click
  	on a mouse.
  Long Trig	Same as Wait Trig, with a longer duration.
  Off Trig	Same as Foot Off, except that after a specified duration
  	after a Foot Off event, Off Trig returns to a value of 0.
  Delta Trig	If the change in pressure exceeds a user-defined value in the
  	positive direction within a given amount of time, output the
  	total pressure at the moment the change in pressure
  	occurred. This allows multiple triggers without requiring
  	the pressure to fall below the Foot Off threshold.
  Wait Trig	Same as Trig sources above, except that the output values
  Latch, Fast	do not return to zero.
  Trig Latch,
  Dbl Trig
  Latch, Long
  Trig Latch
  Nav Y	If the pressure exceeds a user-defined value on the North
  	quadrant of the Nav Pad, then increase the current value of
  	the Nav Y source by one. If the pressure exceeds a user-
  	defined value on the South quadrant of the Nav Pad, then
  	decrease the value of the Nav Y source by one. The
  	source's value cannot be increased or decreased by more
  	than one until the pressure of the activated quadrant has
  	fallen below the defined pressure threshold value.
  Nav Y ×	Multiplies the Nav Y source by 10, and adds the value of
  10 & Key	the key number to it. If Nav Y = 10, and key 1 is hit,
  	Nav Y × 10 & Key outputs 11.
  Key Value	If total pressure of a key exceeds the user-defined pressure
  	threshold (i.e. Foot On), then output the value of the key
  	pressed (0-9).
  Prev Key	When a new Key Value is received, Prev Key Value
  Value	outputs the previous value. If the user presses key 4, and
  	then presses key 7, Prev Key Value outputs a value of 4.
  This Key	Same as Key Value, except outputs the value of the key
  Value	pressed, only if it is equal to the value of the key in which
  	the source is selected.
  Key #	Same principle as Key Value. IfKey 3 Pressed is selected,
  Pressed	and the pressure exceeds the threshold of key three,Key 3
  	Pressed outputs a 1. If any key other than 3 are pressed,
  	Key 3 Pressed outputs 0.

• For some implementations, keys may be near each other as this is desirable to make a smaller device. In order to prevent accidental key operations from a large foot or shoe, several isolation functions may be employed. According to one embodiment, such an isolation function operates by shutting off data input from keys that are not pressed. For example, if the pressure threshold is exceeded onkey1, then all data from other keys' piezo-resistive pads are deactivated untilkey1 is relinquished. Another more advanced approach operates by shutting off data from keys adjacent to the initial desired key after it is pressed. This allows two keys to operate—one per foot—without unintended key activity.
• The multiple sensor arrangements for each key may also be useful for determining which of the closely-spaced keys was selected. For example, if the NW and SW sensors forkey7, the NE and SE sensors forkey9, and the NW and NE sensors forkey3 were activated in conjunction with most or all of the sensors forkey8, then processor could determine that the user intended to selectkey8.
• FIG. 3 shows a cross-section of aSoftStep™ 300 implemented according to a specific embodiment of the invention. In order to get enough stiffness along the longitudinal axis of the SoftStep™, a laminate of fiberglass (e.g., circuit board302), a spacer (e.g., plastic shim304) andcarbon composite306 is employed to act like a box beam. Stiffness is advantageous for keeping the sensors aligned and preventing the electronic components from failing.
• FIG. 4 is a cross-sectional view of a piezo-resistive sensor402 under one corner of akey pad404 for a foot-operated controller implemented according to a particular embodiment of the invention. Piezo-resistive material406 is glued to aplunger408 at ½ of of the piezo's thickness and held just off a pair of traces on a printed circuit board (PCB)302. When pressure is exerted onkey pad404,plunger408 moves relative to the reliefs surrounding it. A monotonic representation of the pressure being exerted on the sensor is then generated as a voltage as the resistance of the piezo-resistive material in contact with the circuit traces changes correspondingly. This same geometry may be used for all piezo-resistive sensors in the SoftStep™.
• Illumination of the keys and navigation pad (e.g., luminous panel308) may be effected in a number of ways. For example, arrays of LEDs might be employed. Alternatively, given that it may be difficult in some applications to illuminate a relatively broad area with an LED, as well as the potential for hot spots, embodiments are contemplated that employ electro-luminescent resources (e.g., patterned sheets, tubes, etc.) to selectively illuminate portions of the SoftStep™ display area. Still other alternatives might employ phosphorescent materials. In cases where active sources of illumination are employed, the intensity of the illumination may also be modulated to correspond to various inputs, e.g., pressure from the user's foot, musical inputs (e.g., throbbing to the beat), etc. The light intensity may also be automatically dimmed when the pad is not in use.
• FIG. 5 is a diagram illustrating various musical components and sub-systems connected to aSoftStep™ 500 designed for use in musical applications. The SoftStep™ may be used in conjunction with software on a connected computer502 (e.g., via USB) to control effects, looping, sample triggering, etc., using effects processors, MIDI devices and systems, OSC devices and systems, etc. The SoftStep™ may be used with digital audio workstations (DAWs) to control punch-in, panning, levels, and transport functions (e.g.,504). According to some embodiments, the SoftStep™ may be used in standalone mode, i.e., without an external computer, to control aMIDI synthesizer506 and/or aMIDI rack508 with aseparate MIDI Expander510 connected via a USB expansion port. Anexpression pedal512 may be connected to the SoftStep™ via an analog expression port. Amusical instrument514 may be connected to an effects processor (e.g., in MIDI rack508) via an instrument cable (for use without computer), or connected to an audio interface that is connected to the computer (for use with computer). In addition to myriad ways of controlling sound, the SoftStep™ can be used with anything else that will accept MIDI or OSC data, e.g., lighting effects or video (516), robotics, pyrotechnics, and more.
• MIDI expander510 is an optional device that enables use of the SoftStep™ to control MIDI devices and systems without an external computer. Once the SoftStep™ is configured with control mapping software as described below, any MIDI device may be connected to and controlled by the SoftStep using the MIDI expander. The MIDI expander contains a driver and optical isolator as per MIDI requirements to buffer the RX and TX signals coming from the SoftStep's CPU UART. The MIDI expander connects to the SoftStep using a USB A-to-MIDI USB 4-pin cable. The MIDI expander is connected to power by using a USB A-to-USB B cable and a USB power plug. Other expanders, such as an analog control voltage output group or a bank of relay closures for hardware effects switching can be daisy-chained on the expander bus for greater flexibility. Through the use of such expanders, control data can be simultaneously available to different targets through different hardware standards, e.g., MIDI, Control Voltage DACs, relays, etc.
• According to various embodiments of the invention, the SoftStep™ is employed with a software application (the SoftStep™ application) on a USB connected computer (e.g., computer502) to enable the creation of powerful control parameters. The SoftStep™ application may be implemented using any of a wide variety of software and programming tools and may employ any of a wide variety of connection types, communication protocols, and messaging formats. The computing platform on which the SoftStep™ application operates uses memory to store data, algorithms, and program instructions configured to enable various of the functionalities related to the present invention. Such data, algorithms, and program instructions can be obtained from any of a variety of computer-readable storage media examples of which include magnetic and optical media as well as solid state memory and flash memory devices.
• The SoftStep™ application works with the SoftStep™ foot-operated controller to manipulate sensor data that gives the user a nearly infinite degree of control and possibility. As discussed above, the SoftStep™ has 10 key pads, each with multiple sensors, enabling 5 degrees of freedom that are unique to each key. As shown inFIG. 2 on the enlarged representation of key pad “8,” these parameters include X-axis, Y-axis, clockwise (CW) rotation, counter-clockwise (CCW) rotation, and pressure (Z-axis). These sources can be mapped to destinations up to six times for each key providing the possibility of a dense data source from a single motion of the foot. It should be noted that, while operation of the SoftStep™ application is described herein with reference to a particular implementation of the SoftStep™ controller, the functionalities of the SoftStep™ application are not limited to the controller design described. That is, the various functionalities of the SoftStep™ application may be employed to interface with and configure virtually any controller intended for similar applications.
• The main window for a particular implementation of the SoftStep™ application is shown inFIG. 6. The controls for the numbered key pads and the Nay Pad are arranged in a manner similar to the corresponding controls on the SoftStep™ itself. Each key and the Nay Pad has a corresponding modulation window (discussed below) in which the sources visible from the sensor view (discussed below) can be mapped to various destinations of the user's choice using modlines. These include MIDI, tape recorder style Transport Control destinations, or Ethernet. As will be discussed, each modulation window includes 6 modlines which means that each of the 10 SoftStep™ keys can be configured to control 6 different MIDI messages. After the modlines are set up, this information may be saved into presets for each key. The presets may then be saved into “scenes” from the main window. Additionally, the user can move from scene to scene in whatever order he chooses by using a setlist.
• The x-axis of the diamond-shaped Nay Pad is configured to scroll through the scenes in a setlist. Each time the user navigates back to any scene in the current setlist, the last state of that scene will be remembered so the user can pick right back up where he left off. For example, assume that for one scene all of the program change messages have been set up. Once these edits are complete, the user navigates to a different scene, e.g., one that is set up to control a looper. After turning on some loops, the user then navigates back to the program change scene, for which the last program change message sent out will be recalled. Then, when the user navigates back to the looper, the LED indicators representing the loops turned on the last time the user was in that scene will be recalled. Then, by tapping either up or down on the Nav Pad, the last data sent from that scene will be displayed in the alpha numeric display until another key is pressed.
• The SoftStep™ application also provides the user with the ability to alter the sensitivity settings for the numbered keys and the Nav Pad. Accessible from the main window, the settings window also enables the user to set up a MIDI input device for use with the MIDI expander, and to calibrate an expression or volume pedal for use with the SoftStep™ expression port. MIDI input can then be used as sources in the Preset Modulation window, also accessible from the Main window. The user can use Preset Modulation to allow other MIDI controllers to change scenes or presets for the keys or Nav Pad.
• Referring once again toFIG. 6, the main window of the SoftStep™ application includes 10 blocks that correspond to the 10 numbered keys on the SoftStep™ controller. Each numbered block provides access to presets for the corresponding key. These presets can be edited by selecting the modulation box within each key block. In addition, when the user steps on a key pad on the SoftStep™ controller, a blue background appears around the corresponding key block in the main window of the SoftStep™ application. To the right of the key blocks are four dark grey boxes that mirror what is displayed on the LED display on the SoftStep™ controller. Under these is the control block for the Nav Pad which allows the user to control the settings for the diamond-shaped navigation pad on the right side of the SoftStep™ controller.
• The top left corner of the main window of the SoftStep™ application includes the scenes control block which allows the user to save and recall presets that belong to particular scenes. Each scene may encompass10 presets of the 10 keys, a preset modulation, and the presets for the Nav Pad. Below the scenes control block is the setlist control block which allows the user to specify an order for a group of scenes that is useful, for example, for a performance That is, the order in which scenes are created and saved during programming of the SoftStep™ might not be the order the user wants for a given performance. The use of setlists allows the user to save and navigate through the scenes in any order.
• The scene abbreviation allows the user to set what the SoftStep™ display reads when a scene is first selected. The preset modulation control allows use of the MIDI input sources to control presets. For example, the user might set up a MIDI input that can be used to change the preset to whichkey1 is set.
• To the right of the preset modulation control is the settings control, selection of which opens the settings window and allows selection of presets that determine how the application will scale and accept data from the SoftStep™ controller. The settings window also allows the user to set up an Ethernet OSC port and declare MIDI channels. Above these controls is the sensor view button. When selected, a user interface is presented that shows how the SoftStep™ controller is sensing data.
• As discussed above, at the top of the main window is the control block that enables the user to save scenes. Also each key block provides the controls that enable the user to save presets for the corresponding keys. The manner in which each facilitates saving presets or scenes is substantially the same. To save a scene or preset, the user selects the “Save” button in the corresponding control block and enters the name of the scene or preset in the box presented (not shown). Multiple presets may be saved for each. And once saved, each preset may be readily recalled using the increment/decrement control in either the key's modulation window or from the SoftStep™ application main window. In addition, when scenes or presets are saved in with the SoftStep™ application this information is stored in a folder and may be retrieved if lost or if the user upgrades to a newer version of the software.
• According to some embodiments, the SoftStep™ application enables the user to program the presets for the keys to recall initial states the first time a scene is recalled at the beginning of a session, e.g., when the SoftStep™ application is started and/or the SoftStep™ controller is turned on. After a scene is recalled for the first time in a session, the user's interaction with the SoftStep™ will then change the states of the keys. As discussed above, if the user navigates to a different scene and then returns, the last state of that scene will be recalled rather than initial states.
• Selection of the “Open” button in the setlist control box in the main window of the SoftStep™ application results in presentation of the setlist window for that setlist as shown inFIG. 7 which includes an array of text fields and number boxes. The circle buttons in front of each line are used to turn on or off a scene appearing in the text field. The user may select the scene in the text field by scrolling through the numbers or pressing the increment/decrement arrow controls on the right hand side. The order of scenes listed in the setlist is the order of scenes as they will be recalled using the x-axis of the Nay Pad.
• The portion of the settings window shown inFIG. 8 (accessed via the setting control block in the SoftStep™ application main window) allows the user to edit sensitivity parameters for each key. The keys settings shown in Table 2 and the Nay Pad settings shown in Table 3 may be manipulated via this portion of the settings window.

• TABLE 2
  Key setting	Description
  Rotation slew	rotation plots the location of your foot on the key
  	around a dial that goes from 0-127 which is then
  	available as a source for data mapping. The rotation
  	slew setting allows you to add slew while scrolling
  	through the dial values, allowing you to slow down
  	the rotation.
  Dead X	this parameter designates the width of the horizontal
  	dead zone, which indicates how much more weight to
  	one side you need to be pushing down with in order
  	to begin incrementing or decrementing.
  Accel X	this is how fast the inc/dec for the horizontal plane
  	moves. The higher the value, the faster you'll move
  	from one side to the other.
  Dead Y	designates the width of the vertical dead zone, which
  	indicates how much more weight to the top or bottom
  	you need to be pushing down with to begin
  	incrementing or decrementing.
  Accel Y	this is how fast the inc/dec for the vertical plane
  	moves.
  On thresh	here you can set the sensitivity for the “foot on”
  	threshold. For example, if set to 7 you would have to
  	put enough pressure on the key for it to register a
  	value of 7 before the “foot on“ trigger is sent.
  Off thresh	here you can set the sensitivity for the “foot off“
  	threshold. For example, if set to to 7, the pressure
  	value would have to be 7 or lower for the “foot off”
  	trigger to register. You would want this to be lower
  	than the “on“ sensitivity.
  Delta	If there is a positive change in pressure greater than
  	the delta value it sends the delta trigger value that
  	you can use as a modulation source
  Global gain	amplifies all incoming data from each key. Adjust
  	this first before adjusting other settings. This scales
  	all of the sensor data from the SoftStep ™ keys and
  	can make the SoftStep ™ more or less responsive to
  	pressure. If you are 2 meters tall and 110 KG you
  	would need less global gain than if you weighed half
  	that.
  Multiple key	turn this on to be able to use two keys at a time - one
  mode enable	per foot. The SoftStep ™ automatically determines
  	the key you mean to press and disallows adjacent
  	keys from accidentally firing. Normal setting (off)
  	allows just one key at a time to be active.

• TABLE 3
  Nav Pad Setting	Description
  Dead X/Y	select the “dead zone” for the X and Y axis of the
  	Nav Pad
  On thresh N, S,	just like for the regular keys you can set the
  E, W	sensitivity for the “foot on” threshold for the Nav
  	Pad. If set to 7 you would have to put enough
  	pressure on the key for it to register a value of 7
  	before the “foot on” trigger is sent.
  Off thresh N, S,	just like for the regular keys you can set the
  E, W	sensitivity for the “foot off” threshold. For example,
  	if set to 7, the pressure value would have to be 7 or
  	lower for the “foot off” trigger to register. You would
  	want this to be lower than the “on” sensitivity.

• The portion of the settings window shown inFIG. 9 (accessed via the setting control block in the SoftStep™ application main window) allows the user to set up a MIDI Input device, an OSC port, and calibrate an expression pedal. The settings shown in Table 4 may be manipulated via this portion of the settings window.

• TABLE 4
  Control	Description
  MIDI enable	turn on or off lines that receive MIDI Input data
  MIDI device	set where the MIDI Input data is coming from
  MIDI channel	set which channel the MIDI Input data is coming
  	from
  MIDI parameter	choose between note, controller, or program change
  	for what type of data is coming in
  #	if you chose note or controller for your parameter
  	then you can choose which control number or note
  	value the data is for
  MIDI value	shows the data coming in from the MIDI Input device
  OSC IP	select the IP address for where the OSC is being sent
  	to
  OSC port	select which port the OSC output is going to

• If an expression pedal is plugged into the expression port of the SoftStep™ controller, the Pedal Calibration button shown inFIG. 9 will facilitate calibration. Selection of the Pedal Calibration opens a window which provides step-by-step calibration instructions. This interface may also be used to calibrate a volume pedal where the plug is in the Instrument Output jack of the volume pedal.
• The sensor view window shown inFIG. 10 provides visual representations of the sensor data coming from the SoftStep™. Each key window displays a number of parameters for the corresponding SoftStep™ key. The rotation dial plots where the user's foot is on the corresponding SoftStep™ key around a dial that the user can rotate. For example, if the user's foot is in the bottom left corner of the key the rotation dial will be turned all the way down. The user can then turn it all the way up by rotating his foot around the key to the bottom right corner.
• The xy latch display shows the x- and y-axis position of the user's foot on the key. The “latch” indicates that when the user releases the key, this value will stay where he left it. The pressure latch display shows the pressure of the user's foot on the key and will also stay where the user leaves it. The inc/dec display shows the user's foot incrementing and decrementing through the horizontal and vertical planes of the key. Stepping a few times on one side of the key results in the value incrementing or decrementing by different amounts according to the pressure. The user can also hold pressure onto one side and it will increment or decrement smoothly toward one side. These values will show up in the modlines as “horizontal” and “vertical.” The dead zone and rate of change for this display may be set in the settings window.
• The live display gives real-time readings of non-latching parameters, i.e., pressure, x, and y. The foot on/foot off display shows whether or not the key is active or has been active. For example, notice inFIG. 10 that some of the keys don't have the “foot on” or “foot off” indicators illuminated (i.e., keys 7-0). This indicates that these are the keys that have not yet been touched during this session, which also explains why all of these keys show their initial states for every parameter. Also notice inFIG. 10 that some of the keys have at one time been activated but are not currently activated (keys 1-5). The “foot off” indicators for these keys are on and all of the latch indications and the inc/dec and dial indicators show their last state. The only thing that doesn't latch is the live indicator.Key6 is shown to be in use, i.e., it is highlighted in blue, the “foot on” indicator is lit, and sensor data are shown in the live display.
• Referring once again toFIG. 6, some of the functions associated with each key block in the main window of the SoftStep™ application will now be discussed. Selection of the “save” button in a key block saves a preset for the corresponding key. Presets may also be saved from within the key's modulation window. Selection of the “copy” button allows the user to copy settings from one key to another. Selecting the copy button in one key block changes the copy buttons in all other keys block into “paste” buttons. The settings from the first key may then be copied into any of the other keys by selecting the corresponding paste button. Selecting the copy button in the first key block again returns the button to read “copy.” The circle to the right of the copy button mirrors the programmable LED status on the SoftStep™ controller.
• Selecting the “modulation” box in a key block brings up the modulation window for that individual key (as shown inFIG. 11) allowing the user to edit the parameters in the displayed preset. Clicking on the little arrows next to the preset number will scroll up and down through the presets saved for that modulation window.
• The modulation window shown inFIG. 11 includes an array of “modlines” that can be configured for each key. In the embodiment shown, there are six modlines that can assign six parameters of the corresponding SoftStep™ key to output different types of messages. According to the depicted embodiment, each modline has the options shown in Table 5.

• TABLE 5
  Modline
  Option	Description
  On/off	click on the circle to enable the modulation line and it
  	will show a blue-green color. When disabled, the
  	modline on/off appears dark
  Init	the initial value. Adjust the initial value to preview what
  	that value does to the rest of the modline. This is also
  	the starting value in the absence of any raw data from
  	the source
  Sources	Choose what data source will control the individual
  	modline. Click on the box and many parameters will
  	pop up in a scroll menu. For a representative list of
  	sources see Table 6
  Raw	The value coming directly from the source is displayed
  	here
  Gain	this is the first place where you can use math to modify
  	the signal. Whatever number is put in the gain box is
  	used to multiply the raw value. For example if the
  	source is X live, clicking on the gain window and typing
  	“2” will double whatever value received from the
  	controller
  Offset	set a value to add or subtract from the raw value after it
  	has been multiplied by the gain value
  Result	the resulting value of the source modified by gain and
  	offset
  Table	the result value is entered into the selected lookup table,
  	and used to plot the index on a chart. There are a
  	number of table options, each which will affect the
  	modulation differently as it changes value over time.
  	There is also a toggle option
  Min/max	The “min” and “max” in the output segment allow you
  	to set where the index starts and ends. If the min is set to
  	10 and the max is set to 15, then the index will only
  	count between 10 and 15
  Slew	Use slew to smooth out the index when it jumps from
  	one number to another. The larger the slew, the slower
  	the result will respond to the source
  Parameter	Click on the drop-down menu to see the many options
  destination	available: Note, CC, Bank, Program, OSC (Open Sound
  	Control), Pitch Bend, MMC (MIDI Machine Control),
  	Aftertouch, or Poly Aftertouch. These options are
  	further customizable by selecting the device/route, the
  	note, velocity or control change, or the channel # you
  	wish to send these parameters out

• At least some of the SoftStep™ sources available in every key's modline are shown in Table 6.

• TABLE 6
  SoftStep ™ Sources	Description
  Pressure Live	Similar to Pressure Latch described above, but
  	instead the value resets back to 0 when key is
  	depressed.
  X Live	Similar to X Latch described above, but instead the
  	value resets back to 64 (centroid value between 0
  	and 127) when key is depressed.
  Y Live	Similar to Y Latch described above, but instead the
  	value resets back to 64 (centroid value between 0
  	and 127) when key is depressed.
  Pressure Latch	This value corresponds to the overall pressure
  	sensed by the key (a higher value indicates more
  	pressure applied). The term “latch” indicates that
  	after the foot is taken off, the last recorded value
  	still remains and will not be reset back to 0 (unlike
  	Pressure Live).
  X Latch	This value corresponds to the overall pressure in
  	the X or horizontal direction of the key. Applying
  	more pressure to the right side of the key increases
  	the value, while pressure to the left decreases. The
  	term “latch” indicates that after the foot is taken off,
  	the last recorded value still remains and will not be
  	reset back to 0 (unlike X Live).
  Y Latch	This value corresponds to the overall pressure in
  	the Y or vertical direction of the key. Applying
  	more pressure to the top of the pad increases the
  	value, while pressure to the bottom decreases. The
  	term “latch” indicates that after the foot is taken off,
  	the last recorded value still remains and will not be
  	reset back to 0 (unlike Y Live).
  X Increment	This value corresponds to horizontal value in an
  	increment/decrement style. Step a few times on the
  	right side of the key and see the value increment by
  	different amounts corresponding to the pressure,
  	also try stepping a few times on the left and see the
  	value decrement. You can also hold pressure onto
  	one side and it will inc or dec smoothly towards
  	one side.
  Y Increment	This value corresponds to vertical value in an
  	increment/decrement style. Step a few times on the
  	top of the key and see the value increment by
  	different amounts corresponding to the pressure,
  	also try stepping a few times toward the bottom and
  	seeing the value decrement. You can also hold
  	pressure at the top or bottom and it will inc or dec
  	smoothly towards the top or bottom.
  Rotation	With your foot pushing down on the SoftStep ™
  	controller, roll the tips of your toe in a clockwise or
  	counter clockwise oriented movement and watch
  	the values change.
  Rot Relative	no matter where you put your foot initially you'll
  	get an output of 63 (the center of the dial) and then
  	if you rotate your foot clockwise from that the
  	value will go up. If you rotate your foot counter-
  	clockwise from that the value will go down.
  Foot On	This value corresponds to whether or not the key is
  	pressed or not. 1 indicates the foot is on (true) 0
  	indicates foot off (false).
  Foot Off	Opposite logic to Foot On. 1 indicates foot off
  	(true), 0 indicates foot on (false).
  Wait Trig	Short for trigger, the value is received only after a
  	few seconds of your foot being pressed on the key.
  Fast Trig	causes a trigger after the foot comes off the key in a
  	short period of time (quick tap).
  Dbl Trig	Short for trigger double, the value is received only
  	when the pedal senses two quick impulsive steps
  	onto the key.
  Long Trig	This value corresponds to a trigger (a quick and
  	impulsive step) without immediately taking off the
  	foot, while instead holding it for a longer period of
  	time.
  Off Trig	causes a 0 to trigger when your foot comes off the
  	key in a short period of time (quick tap). The rest of
  	the time it outputs a 1.
  Delta Trig	measures change in pressure. If pressure greater
  	than the delta setting in the settings window occurs,
  	then you'll get a trigger.
  Wait Trig Latch	Same as Wait Trig but the value doesn't go back to
  	0 after the trigger
  Fast Trig Latch	Same as Fast Trig but the value doesn't go back to 0
  	after the trigger
  Dbl Trig Latch	Same as Dbl Trig but the value doesn't go back to 0
  	after the trigger
  Long Trig Latch	Same as Long Trig but the value doesn't go back to
  	0 after the trigger
  Pedal	This value is received when a pedal is connected to
  	the SoftStep ™ controller's expression port, next to
  	the USB port.
  Nav Pad Y	This value corresponds to top and bottom pads of
  	diamond shaped Nav Pad on the SoftStep ™
  	controller. Think of this as a counter, where
  	everytime the top pad is pressed the value one is
  	added to the counter, and when the bottom of the
  	Nav Pad is pressed the value one is subtracted from
  	the counter.
  Nav Pad Y and Key	Use this setting to reach larger numbers much
  	quicker than Nav Pad Y. Stepping on the top pad
  	increments the tens digit of the value, similarly the
  	bottom pad decrements the tens digit. The final
  	value is achieved after stepping on one of the 10
  	pads indicating the ones digit. For example, step on
  	the top pad 14 times to increment the counter to 14,
  	then hit thenumber 2 key, and the final value will
  	be 142.
  Key Value	This value corresponds to which of the 10 keys is
  	stepped on. Stepping onkey 7 gives the raw value
  	of 7, stepping onkey 2 gives the value of 2.
  Prev Key Value	This setting remembers the order in which pads you
  	pressed down on and outputs the last key, not the
  	current. If you step onkey 2 thenkey 8, the value
  	output would be 2.
  This Key Value	This source will output whatever key value you are
  	on whenever you step on it. For example, if I am in
  	thekey 7 modulation window and I choose This
  	Key Value as a source, stepping on all other key
  	won't trigger any value except when step onkey 7,
  	and the value “7” will appear.
  Key 1 . . . 10	This source looks for the status of whatever key
  Pressed	you choose. 1 is true if the corresponding key is
  	pressed, it doesn't matter which key you are editing.
  	For example, if I choose theSource Key 4 pressed
  	in a modline belonging tokey 7, the value will only
  	change and become 1 when I step on pad 4
  	(otherwise it stays 0).
  Mod 1 . . . 6 Output	This setting takes the output value from any of the
  	other modlines as the raw value of its own.
  MIDI A . . . H	These receive the values from the lettered MIDI
  	Input in the settings window

• On the right side of the modulation window ofFIG. 11 are controls for setting display information for the LED lights associated with the SoftStep™ key pads and the four-letter alpha-numeric display screen. The top row contains the settings for the alpha-numeric display screen. Setting the display mode is important for getting the desired behavior. There are 5 display modes for a particular implementation as shown in Table 7.

• TABLE 7
  Display Mode	Description
  None	causes the four-letter display box to go blank when
  	using that key
  Always	displays the key name whenever the corresponding
  	key is the most recently activated key
  Once	displays the key name once at the moment it is
  	activated and will then show the prefix and
  	parameter value
  Initial/Return	displays the key name when the key is selected but
  	not active, and will display the prefix and
  	parameter value when in use. This mode works
  	well for continuously changing sources, but not for
  	toggles. When the display is showing a source
  	value and the slew causes the output to persist after
  	the foot is off the key, the display will no longer be
  	updated, even though the parameter is still being
  	altered
  Immed Param	displays the prefix and parameter value when that
  	key is the currently activated key. The key name
  	does not show up in this mode

• The green and red LED modes for controlling operation of the LED associated with each the SoftStep™ keys are also very useful. Each key can be configured to show a red light or a green light in certain circumstances. There are several different modes for each light as shown in Table 8.

• TABLE 8
  LED Mode	Description
  None	the light will not come on in this mode
  True	the light will come on when the output of the key is
  	above 0
  False	the light will come on when the output of the key is
  	0
  Flash True	the light will flash repeatedly when the output of
  	the key is above 0
  Flash False	the light will flash repeatedly when the output of
  	the key is 0
  Flash Fast True	the light will flash quickly when the output of the
  	key is above 0
  Flash Fast False	the light will flash quickly when the output of the
  	key is 0
  Blink True	the light will blink once when the output of the key
  	goes above 0
  Blink False	the light will blink once when the output of the key
  	goes to 0

• If there are multiple modlines for one key, different modes may be configured for the LED lights with each modline, but only one can be the active modline for the LED display. That is the purpose of the little unlabeled button next to the display mode drop-down menus. Whichever modline has the button next to the LED mode selectors illuminated is the one that will send data to the SoftStep™ controller for LED display information. The reminder field next to that is provided so the user can make a note about the modline he created, e.g., to remind the user about the purpose of the modline.
• Referring again toFIG. 6, selection of the modulation box in the Nay Pad control block in the main window of the SoftStep™ application brings up the modulation window for the Nay Pad (as shown inFIG. 12) allowing the user to edit the parameters in the displayed preset. As shown, the Nay Pad modulation window is similar to the modulation windows for each of the 10 SoftStep™ keys. The modline functions are similar to those discussed above with reference to Table 5. One key difference is the portion of the interface in the upper right hand corner labeled “Counters.” This indicates that the Nay Pad value will wrap around the min and max value set to the left. For example, if the min value for a parameter is set to 5 and the max is set to 120, stepping on the pad again when the value is 120 will set it back to 5. The counter can be reset for each axis by clicking on the little circling arrow.
• The Nay Pad modulation window also includes a flash button for the alpha-numeric display. Activation of this control causes the display box to flash. This may be useful, for example, in the “ProgramChange” main preset of the SoftStep™ in which the Nay Pad display is set to flash to indicate that data have not yet been sent out.
• While the invention has been particularly shown and described with reference to specific embodiments thereof, it will be understood by those skilled in the art that changes in the form and details of the disclosed embodiments may be made without departing from the spirit or scope of the invention. For example, although embodiments have been described herein that relate to musical performance and recording, other applications of the multi axes controllers enabled by the present invention are contemplated. Such applications include, for example, editing video, controlling layered functions in graphics and computer aided design (CAD) programs and emulating other computer controllers. For example, the SoftStep can output data formatted similarly to a Waccom type “dig pad” or writing surface. The dig pad can detect the angle and pressure of the pen as well as its x-y location. Data appearing in this format would be easily mapped to graphics and CAD programs allowing more rapid data manipulation.
• In addition, although various advantages, aspects, and objects of the present invention have been discussed herein with reference to various embodiments, it will be understood that the scope of the invention should not be limited by reference to such advantages, aspects, and objects. Rather, the scope of the invention should be determined with reference to the appended claims.

Claims (20)

1. An apparatus, comprising:

a dielectric substrate;

a plurality of conductors on a surface of the dielectric substrate;

piezoresistive fabric in contact with the surface of the dielectric substrate and the conductors, thereby forming one or more sensors; and

circuitry configured to receive one or more signals from the one or more sensors and to generate sensor data based on the one or more signals, the sensor data representing pressure on a surface of the apparatus, the circuitry also being configured to adjust a sensitivity for each of the one or more sensors.

2. The apparatus ofclaim 1, wherein the circuitry is further configured to determine, for each of the one or more sensors, that the sensor is active based on a first value of the sensor data corresponding to the sensor exceeding a first programmable threshold.

3. The apparatus ofclaim 2, wherein the circuitry is further configured to determine, for each of the one or more sensors, that the sensor is inactive based on a second value of the sensor data corresponding to the sensor being below a second programmable threshold, the second programmable threshold being lower than the first programmable threshold.

4. The apparatus ofclaim 1, wherein the one or more sensors comprise a plurality of sensors, and wherein the circuitry is further configured to apply a gain uniformly to values of the sensor data for all of the sensors.

5. The apparatus ofclaim 1, wherein the one or more sensors comprise a plurality of sensors, and wherein the piezoresistive fabric comprises a plurality of pieces, each of the pieces of the piezoresistive fabric corresponding to one of the sensors.

6. The apparatus ofclaim 1, wherein the one or more sensors comprise a plurality of sensors, and wherein the circuitry is further configured to detect motion of an object relative to the surface of the apparatus based on the sensor data.

7. The apparatus ofclaim 6, wherein the circuitry is configured to detect the motion in one or more linear dimensions and one or more rotational dimensions.

8. The apparatus ofclaim 7, wherein the circuitry is configured to adjust the sensitivity of the one or more sensors independently for each of the dimensions.

9. The apparatus ofclaim 1, wherein the one or more sensors comprise a plurality of sensors, and wherein the circuitry is further configured to determine a location of a first object relative to the surface of the apparatus based on the sensor data.

10. The apparatus ofclaim 9, wherein the circuitry is further configured to determine a location of a second object relative to the surface of the apparatus based on the sensor data, contact between the second object and the surface of the apparatus being simultaneous with contact between the first object and the surface of the apparatus.

11. The apparatus ofclaim 1, wherein the one or more sensors comprise a plurality of sensors, and wherein the circuitry is further configured to determine that a first sensor of the plurality of sensors is active, and ignore input from other sensors of the plurality of sensors based on determining that the first sensor is active.

12. The apparatus ofclaim 11, wherein the other sensors include all of the plurality of sensors.

13. The apparatus ofclaim 11, wherein the other sensors only include sensors adjacent the first sensor.

14. The apparatus ofclaim 1, wherein the circuitry is further configured to generate control information from the one or more signals, and to map the control information to a control destination representing operation of a process or device.

15. The apparatus ofclaim 1, wherein the one or more sensors comprise a plurality of sensors, and wherein the circuitry is further configured to determine that a first sensor of the plurality of sensors is active based on input from the first sensor and other sensors of the plurality of sensors adjacent the first sensor.

16. A method, comprising:

receiving a plurality of sensor signals via a plurality of conductors on a surface of a dielectric substrate, the plurality of conductors and the surface of the dielectric substrate being in contact with piezoresistive fabric, thereby forming a plurality of sensors, each of the sensor signals corresponding to one of the sensors; and

generating sensor data based on the sensor signals, the sensor data representing pressure on a surface of an apparatus that includes the sensors, wherein generating the sensor data includes:

applying a gain uniformly to values of the sensor data for all of the sensors; and

adjusting a sensitivity of each sensors.

17. The method ofclaim 16, further comprising determining that a first sensor of the plurality of sensors is active based on a first value of the sensor data corresponding to the first sensor exceeding a first programmable threshold.

18. The method ofclaim 17, further comprising determining that the first sensor is inactive based on a second value of the sensor data corresponding to the first sensor being below a second programmable threshold, the second programmable threshold being lower than the first programmable threshold.

19. The method ofclaim 16, further comprising detecting motion of an object or a location of the object relative to the surface of the apparatus based on the sensor data.

20. The method ofclaim 16, further comprising determining that a first sensor of the plurality of sensors is active, and ignoring input from other sensors of the plurality of sensors based on determining that the first sensor is active.

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