Abstract: This invention is related to user input devices that accept complex user input including a combination of touch and push (or pick) input. The invention provides for selective ignoring or rejection of input received from such devices in order to avoid interpreting unintentional user actions as commands. Furthermore, some input signals can be modified. The selective rejection or modification can be performed by the user interface device itself or by a computing device that includes or is attached to the user interface device. The selective rejection or modification may be performed by a module that processes input signals, performs the necessary rejections and modifications and sends revised input signals to higher level modules.

Abstract: Provided are a multi-touch system and a driving method thereof. The method includes, extracting using a digital processor a touch frequency and at least one angle associated with at least one touch from image information captured by each of at least two cameras, selecting a touch mode on the basis of sum value of the touch frequencies extracted from the image information captured by the cameras, and performing a touch function corresponding to the selected touch mode using a user interface.

Abstract: A touch sensing device capable of accurately detecting a touched position on a touch panel includes a touch panel, a conversion unit and a calculation unit. The touch panel having a plurality of horizontal sensing lines and vertical sensing lines generates a plurality of horizontal sensing signals and vertical sensing signals in response to a touch on the touch panel. The conversion unit generates a plurality of two-dimensional (2D) sensing signals according to the horizontal and vertical sensing signals. The calculation unit determines a touched position on the touch panel according to the 2D sensing signals.

Abstract: A system for controlling movement of a cursor on a display device, the system comprising: a substrate having a position-coding pattern disposed on or in a surface thereof; a sensing device comprising: an image sensor for optically imaging the position-coding pattern; and a processor configured for: generating absolute motion data by determining a plurality of absolute positions of the sensing device relative to the surface using the imaged position-coding pattern; generating orientation data indicative of an orientation of the sensing device relative to the substrate; and using the orientation data to translate the absolute motion data into relative motion data, said relative motion data being indicative of relative motion of the sensing device from the perspective of a user; and communication means for communicating the relative motion data to a computer system; and the computer system configured for: receiving said relative motion data from the sensing device; interpreting said relative motion data as curso

Abstract: At a first time, an image sensor captures a first image including images of an object. At a second time, the image sensor captures a second image including images of the object. A coordinate calculation device calculates a first coordinate of the object at the first time according to the first image, and a second coordinate of the object at the second time according to the second image. A coordinate correction device calculates a displacement between the first time and the second time according to the first coordinate and the second coordinate, and corrects an output coordinate of the object at the second time according to the displacement.

Abstract: Techniques for using multiple sampling frequencies to detect the location of touch inputs of a user at a touch panel of a touch device. A determination is made as to which of and second sampling frequencies is provided to a receiver for use in sampling the touch inputs from the touch panel. The user touch inputs are first sampled from the touch panel during first and second successive time frames using first and second different sampling frequencies, respectively.

Abstract: Pre-stored no-touch or no-hover (no-event) sensor output values can initially be used when a sensor panel subsystem is first booted up to establish an initial baseline of sensor output values unaffected by fingers or other objects touching or hovering over the sensor panel during boot-up. This initial baseline can then be normalized so that each sensor generates the same output value for a given amount of touch or hover, providing a uniform response across the sensor panel and enabling subsequent touch or hover events to be more easily detected. After the initial normalization process is complete, the pre-stored baseline can be discarded in favor of a newly captured no-event baseline that may be more accurate than the pre-stored baseline due to temperature or other variations.

Abstract: A linear compensation method of a touch panel is utilized to a touch control computer system. According to the method, a compensation reference table, including reference temperatures and reference surface resistances at pre-determined reference points having known coordinates at the reference temperatures, is obtained at first. Then, a set of user calibration resistance at the pre-determined reference points is obtained through a user calibration process, so as to obtain ratios of the user calibration resistances to interpolation surface resistances as correction weights. Under different temperature, interpolation surface resistances corrected by utilizing the correction weight to derive the current correction surface resistances that are corrected and nearly identical to actual surface resistances. Therefore, relatively precise coordinates are obtained through resistance-coordinate conversion process.

Abstract: An image pickup apparatus capable of easily improving the detection accuracy of a touching or proximity object is provided. An offset noise (a reset image R) is obtained by an image pickup process in a state (a reset state) in which an image pickup device is initialized. Moreover, a fingertip extraction process is performed in consideration of the offset noise on the basis of a picked-up image (a shadow image A or a display light-using image B) which is obtained by picking up an image of a proximity object to obtain object information about the proximity object. While an offset noise in the apparatus is easily reduced, object information about the proximity object can be obtained.

Abstract: Various apparatuses, methods and systems for detecting simultaneous touches at multiple locates are disclosed herein. For example, some embodiments provide an apparatus for detecting a touch, the apparatus including a resistive touch screen and a controller connected to the touch screen. The touch screen includes a number of electrically conductive columns and rows. In various embodiments, the touch screen is an analog matrix, with the overlapping columns and rows forming a matrix of cubics that can each detect one touch at a time, and with the location of the touch detectable in an analog fashion within each cubic. The resolution of the analog matrix in these embodiments is thus higher than that of the columns and rows. The controller includes an analog to digital converter switchably and sequentially connected to each of the columns and rows. The controller also includes a voltage source switchably and sequentially connected to each of the columns and rows.

Abstract: This is related to user input devices that accept complex user input including a combination of touch and push (or pick) input. The invention provides for selective ignoring or rejection of input received from such devices in order to avoid interpreting unintentional user actions as commands. Furthermore, some input signals can be modified. The selective rejection or modification can be performed by the user interface device itself or by a computing device that includes or is attached to the user interface device. The selective rejection or modification may be performed by a module that processes input signals, performs the necessary rejections and modifications and sends revised input signals to higher level modules.

Abstract: A touchpad assembly for use in an electronic device is provided. The touchpad assembly may include a touchpad frame operative to be placed within an opening in an electronic device frame. The touchpad assembly may include a support plate for supporting a touchpad, and a bracket for receiving a pick button. The support plate and bracket may be manufactured into a same component to increase the rigidity of the touchpad assembly. The pick button may include a varying height to prevent the pick button from deflecting and to make the pick button travel for providing a selection instruction uniform. The pick button may be coupled to the frame using any suitable approach, including using springs connected the ends of the pick button to the frame. The frame may also include pads to muffle the sound of the pick button when it returns to its initial position after having been pressed.

Abstract: An input processing device comprises a display screen and a pointing device for inputting corresponding 2-dimensional coordinates on the display screen. A 3-dimensional space is displayed on the display screen and the 2-dimensional coordinates inputted from the pointing device are detected. Next, shift amounts, per unit of time, of the detected 2-dimensional coordinates are calculated based on a predetermined calculation start condition. And the calculated shift amounts are converted to 3-dimensional coordinate shift amounts in the 3-dimensional space.

Abstract: At a first time, a first image sensor and a second image sensor capture a first image and a second image including images of an object respectively. At a second time, the first image sensor and the second image sensor capture a third image and a fourth image including images of the object respectively. A coordinate calculation device calculates a first coordinate of the object at the first time according to the first image and the second image, and a second coordinate of the object at the second time according to the third image and the fourth image. A coordinate correction device calculates a displacement between the first time and the second time according to the first coordinate and the second coordinate, and corrects an output coordinate of the object at the second time according to the displacement.

Abstract: A touch panel capable of decreasing concavity and convexity generated on the surface and a display unit including the same are provided. The touch panel includes: a first spacer layer on both side faces of a first wiring layer provided on a first transparent substrate; and a second wiring layer on both side faces of a second wiring layer provided on a second transparent substrate. The touch panel also includes a flexible printed circuit board in a gap between the first transparent substrate and the second transparent substrate and in a region including at least part of a region not provided with the adhesion layer in the region opposed to the first wiring layer, the second wiring layer, the first spacer layer, and the second spacer layer.

Abstract: An operation device includes: a touch panel on which at least one operation button is displayed; a press position detection unit detecting a press position when a user presses the touch panel; a button operation detection unit determining whether an operation is applied to the operation button based on the press position; a button operation appropriateness determination unit determining whether a button operation by the user is appropriate; and a button operation facilitating unit facilitating subsequent button operations by the user when it is determined by the button operation appropriateness determination unit that the button operation by the user is inappropriate.

Abstract: An operation device includes: a touch panel on which at least one operation button is displayed; a press position detection unit detecting a press position when a user presses the touch panel; a button operation detection unit determining whether an operation is applied to the operation button based on the press position; a button operation appropriateness determination unit determining whether a button operation by the user is appropriate; and a button operation facilitating unit facilitating subsequent button operations by the user when it is determined by the button operation appropriateness determination unit that the button operation by the user is inappropriate.

Abstract: The detection of touch on an optical touch-sensitive device is disclosed. For example, one disclosed embodiment comprises a touch-sensitive device including a display screen, a laser, and a scanning mirror configured to scan light from the laser across the screen. The touch-sensitive device also includes a position-sensitive device and optics configured to form an image of at least a portion of the screen on the position-sensitive device. A location of an object relative to the screen may be determined by detecting a location on the position-sensitive device of laser light reflected by the object.

Abstract: Touch sensor methods, devices and systems are disclosed. One embodiment of the present invention pertains to a method comprising monitoring a finger movement along a touch sensing surface based on position data of a finger touching the touch sensing surface, where the position data is obtained by locating a position of a force applied by the finger in a coordinate of the touch sensing surface. In addition, the method comprises generating direction data associated with the finger movement if the finger movement travels for more than a threshold distance. Furthermore, the method comprises determining a finger gesture which corresponds to the finger movement using a lookup table having multiple preconfigured finger gestures based on the direction data.

Abstract: A method for using a touch display system comprises defining local distortion zones within regions of a touchscreen. Each of the local distortion zones has an associated calibration touch point and a target. Coordinates of a user touch point are distorted within a first local distortion zone based on a location of the user touch point within the first local distortion zone.

Abstract: Detect four sets of first touch coordinates (A, B, C, D) on a touch panel. Divide an area delimited by the detected four sets into two areas of triangles (ABD, BCD). For each area of triangle, obtain a first correction factor. Detect a set of second touch coordinates (P, Q) selected within a respective one of the areas of triangles. Convert the detected set of second touch coordinates into a set of first corrected coordinates. Detect a difference between the set of first corrected coordinates and a set of true display coordinates. Where the detected difference is greater than a predetermined threshold value, further divide the area of triangle (BCD) into three areas of triangles (QBD, QBC, QCD). Obtain a second correction factor using the set of second touch coordinates and the sets of first touch coordinates corresponding to the vertices.

Abstract: A computer as an input adjustment apparatus includes a memory. This memory stores an input adjustment program. The computer is connected with a touch pad. When a user touches the touch pad with his/her finger, the computer is provided with touch coordinate data on a touched portion and a value according to an area of the touched portion. Based on the coordinate data and the value according to the touch area, the computer calculates a scale factor of a range in which the user can actually perform an operation in such a manner as to conform to a whole operating range of the touch pad. Then, the computer multiplies by the scale factor a difference of coordinates indicated by the coordinate data (current touch coordinates) from a reference position, and input the resulting value as input data into an electronic device.

Abstract: An angle correcting method for a position pointer induced by a handwritten input device is disclosed. The steps of the method includes: firstly, an inclined angle table is provided. Then, a first induced voltage amplitude of a first position where the position pointer touches and a second induced voltage amplitude of a second position where is near to the first position are induced. The ratio of the first induced voltage amplitude to the second induced voltage amplitude is calculated to generate an amplitude ratio. Finally, the inclined angle table is looked up to find an inclined angle according to the amplitude ratio.

Abstract: Anti highlight structure for a touch panel includes a touch film of a flexible transparent thin film, a substrate of a rigid transparent plate, and a touch sensing unit has two sheets of transparent conductive film arranged with a predetermined gap between the touch film and the substrate. It further includes an anti Newton-Ring layer of a transparent thin film having at least one uneven and rough surface thereof, and a light regulating layer of a transparent thin film. A plurality of transparent granular objects is bound in a transparent matrix of the light regulating layer. The transparent granular objects and the transparent matrix have different indexes of refraction. The transparent granular objects are made of at least one material. The lights will be corrected by the complex indexes of refraction within the light regulating layer so that the highlights causing an image distortion and deformation will be eliminated.

Abstract: A display device having a contact sensing function, and a driving method thereof are disclosed in one embodiment.

Abstract: A computer readable medium has instructions to calibrate a touch system by detecting touch points on a touchscreen that are each associated with touchscreen coordinates in a touchscreen coordinate system. The instructions associated each of the touch points with known calibration targets, and each of the calibration targets has display coordinates in a display coordinate system that is associated with at least one of a display screen and an operating system. The instructions fit the display coordinates and the touchscreen coordinates non-linearly with respect to each other based on a generalized Laplace-constrained fit that is used to identify correction parameters used to map a user generated run-time touch point on the touchscreen to a display coordinate location on a display screen. The correction parameters represent non-linear corrections.

Abstract: Methods and systems are provided for automatically calibrating a pointing device, such as a stylus, with a writing surface, such as a touch screen. In one example, an automated method is implemented to calibrate the writing surface based user inputs attempting to use the computer for functions other than calibration of the writing surface. The user inputs may be, for example, a user selecting a button within a non-calibration software application. The automated method may generate a miscalibration vector based upon where the user input was received and where the user input was expected. In yet another example, a bias field may be generated for the writing surface from the collected user inputs. In yet other examples, a computing device may comprise computer-executable instructions for performing one or methods of calibrating the writing surface.

Abstract: Methods, computer program products, computing and printing systems for improved screen display and touch input, where an operation/display unit comprises a screen display unit such as a LCD; a touch location detection unit, which is a touch panel that accepts a user's touch operation; a touch decision unit that determines the touch location of the user's touch operation to the touch panel; and a touch execution unit that executes functions according to the user's touch location. If the user's touch location is within the effective area(s) of the operation button(s), then the touch execution unit executes the function allocated to the operation button(s). If the touch location is outside of the effective area(s) of the operation button(s), then the region outside of the operation button(s) is displayed as grayed-out.

Abstract: Respective demodulated outputs from a plurality of branches 11a to 11d are fed to corresponding error correction units 13a to 13d and error-corrected. The error correction units 13a to 13d feed error signals to error determination units 14a to 14d. The error determination units 14a to 14d determine the error-incidence situations of the respective branches 11a to 11d and then output the determination results to a coefficient generation unit 15. Based on the results of determination by the error determination units 14a to 14d, the coefficient generation unit 15 obtains the synthesis coefficients for the respective branch outputs. The synthesis coefficients correspond to the error-incidence situations of the respective branch outputs and are appropriate values including no errors. By synthesizing the respective branch outputs by use of the synthesis coefficients, error-free data can be reproduced.

Abstract: An electrical touch pad includes a touch sensor for detecting operational inputs, and generating analog signals according to the operational inputs; a touch detection unit for receiving analog signals, amplifying the analog signals by a controllable gain to generate amplified analog signals, converting the amplified analog signals to generate digital signals, and sending the digital signals to a processor to determine a touched location; a humidity detection unit for detecting ambient humidity and determining a humidity level; and a humidity compensation unit for receiving the humidity level, generating a gain regulation signal to control the touch detection unit to regulate the controllable gain according to the humidity level. Thereby, in erratic behavior of the electrical touch pad can be prevented and stability of the touch pad is enhanced. A related method for regulating sensitivity of the electrical touch pad is also provided.

Abstract: A system for determining at least one point of application of force on a surface element is provided. The system includes a surface element having an effective mass, at least one sensor configured to measure force applied on the surface element at least one acceleration sensor configured to measure acceleration in at least one direction, and a processing unit configured to receive, from the at least one sensor, signals indicating force applied on the surface element, to receive, from the at least one acceleration sensor, signals indicating acceleration, to filter out a disturbing force, determined based on acceleration signals and the effective mass of the surface element, from the signals indicating the force applied on the surface element, and to determine, based on the filtered signals, at least one point of application of force on the surface element.

Abstract: A control device for a capacitive touch panel has multiple voltage driving/current detecting circuits respectively connected to four corners of a top conductive layer of the touch panel. An auxiliary voltage driving/current detecting circuit is connected to a bottom conductive layer of the touch panel. When the touch panel is pressed, all voltage driving/current detecting circuits detect first current values at four corners of the top conductive layer. The auxiliary voltage driving/current detecting circuit also detects a second current value from the bottom conductive layer. The second current value is used to compensate all first current values so that the coordinate information of the position being pressed can be exactly calculated.

Abstract: A computer as an input adjustment apparatus includes a memory. This memory stores an input adjustment program. The computer is connected with a touch pad. When a user touches the touch pad with his/her finger, the computer is provided with touch coordinate data on a touched portion and a value according to an area of the touched portion. Based on the coordinate data and the value according to the touch area, the computer calculates a scale factor of a range in which the user can actually perform an operation in such a manner as to conform to a whole operating range of the touch pad. Then, the computer multiplies by the scale factor a difference of coordinates indicated by the coordinate data (current touch coordinates) from a reference position, and input the resulting value as input data into an electronic device.

Abstract: Motion of a writing instrument is tracked from sensors located in the vicinity. The signals generated from the sensors are processed and used in a wide variety of ways.

Abstract: A method and system for visually tracking a point of contact of an optical output from a computer input device includes an internal camera configured to visually track the point of contact of the optical output against a surface and an optical source to transmit the optical output from the computer input device. The camera also transmits the position of the point of contact as a computer input. In one form, the computer applies the position of the point of contact as an input to an application operating on the computer, such as a gaming application. In one form, the camera can visually track the movement of the computer input device along a surface.

Abstract: A touch sensing device for increasing the sensitivity of a touch sensor is disclosed. The touch sensing device comprises: a touch sensor array including a plurality of touch sensors; and a swing level correction unit for correcting each of touch data from the touch sensor array by a difference value with neighboring another touch data to generate correction values and correcting the swing levels of the touch data by adding an offset value to the correction values.

Abstract: A touch sensing apparatus is provided. The apparatus includes a flip-flop (15), a sensor (13), an AC signal (14), and a detector (16). The AC signal supplies AC signals to the flip-flop. The flip-flop outputs a first output signal at the output of flip-flop when the sensor is not touched. The sensor receives electricity signals from the object, and causes a delay of the AC signal inputted to the first input of the flip-flop, the delay of the AC signal to be inputted to the first input of the flip-flop further causes the flip-flop to output a second output signal at the output of the flip-flop. The detector detects a change from the first output signal to the second output signal at the output of the flip-flop and accordingly identifies a touch on the sensor.

Abstract: A touch sensing apparatus is provided. The apparatus includes a sensor (13), a flip-flop (16), and a microcontroller unit (17). The sensor is connected to one of input of the flip-flop for receiving electricity signals from an object that touches the sensor. The MCU respectively supplies two AC signals at two outputs thereof to two inputs of the flip-flop. The flip-flop outputs a first type output signal at the output thereof when the sensor not being touched. When being touched, the sensor receives electricity signals from an object, and causes a delay of an AC signal to be inputted to the input of the flip-flop to which the sensor is connected, the delay of the AC signal to be inputted to the input of the flip-flop further causes the flip-flop to output a second type output signal at a output thereof. The MCU detects a change of the output signals of the flip-flop from the first type output signal to the second type output signal and accordingly identifies a touch on the sensor.

Abstract: A touch sensing apparatus is provided. The apparatus includes: a flip-flop, a sensor, an AC signal and a detector. The AC signal supplies AC signals to the flip-flop. The flip-flop outputs a first type output signal at the output thereof when the sensor is not touched. The sensor receives electricity signals from an object, and causes a delay of the AC signal to be inputted to the first input of the flip-flop, the delay of the AC signal to be inputted to the first input of the flip-flop further causes the flip-flop to output a second type output signal at the output thereof. The detector detects a change from the first type output signal to the second type output signal at the output of the flip-flop and accordingly identifies a touch on the sensor.

Abstract: A method and system for correcting alignment and linearity errors in devices using a finger or stylus input device with a display device interactively coupled to a digitizer is disclosed. Touching intersections in a calibration grid on the display device may be performed to create a linearity map. Subsequently, detected stylus input is mapped to a sector in the linearity map, and resultant screen coordinates are calculated using ratios within a reference rectangle corresponding to the detected stylus input and the mapped sector.

Abstract: The invention relates to a resistive touch-sensitive device for detecting a short-term or long-term dysfunction by means of measuring devices (32,33), a monitoring device (34) and a memory (35) in such a way that a timely signaling is carried out.

Abstract: The present invention discloses systems and methods for use with vibration sensing touch input devices that distinguish signals derived from vibrations on a touch plate due to a touch input from signals derives from electromagnetic interference. In the present invention, the phase response of the signals due to electromagnetic interference can be inverted relative to the phase response of the signals due to vibrations in at least one signal transmission channel so that pair wise cross-correlation of the various signal channels reveals the signals caused by electromagnetic interference. Once electromagnetic interference is identified, it can be ignored or otherwise appropriately taken into account by the system.

Abstract: A height dependent filter for a pointing device or digitizer tablet, a method of reducing jitter in position data of a pointing device, and a computer readable medium are provided. A method of stabilizing positional data in a digitizer tablet associated with a display device for reporting a position of a pointer includes detecting a current location of the pointer with respect to a coordinate grid defined on the tablet and outputting a position signal indicative of the current pointer location. Noise is filtered from the position signal based on at least one filter parameter. A distance between the pointer and a point on the tablet is determined, and an amount of jitter in the position signal is determined based on the determined distance. The at least one filter parameter is adjusted based on the estimated amount of jitter.

Abstract: A linear compensation method for touch control systems aims to provide an accurate correction for the depressing electric field that generates signal sources in a touch control system. Through a voltage detection and compensation approach, and after the touch control system has been shipped from the plant with correction done for a rated duty voltage or set duty voltage, and is installed on an operation environment and receives an actual duty voltage, the linear compensation method of the invention updates the linear compensation data according to the voltage variation between the actual duty voltage and the rated or set duty voltage thereby to maintain accurate depressing electric field at the duty voltage for the touch control system.

Abstract: Disclosed herein is a device including a differential amplification unit for supplying current to the touch panel; a signal amplification unit for amplifying the output voltage of the differential amplification unit; an analog-digital conversion unit for converting the analog output signal of the signal amplification unit into a digital signal; a control unit for measuring the signal output from the analog-digital conversion unit and detecting the position of an object when the object touches the touch panel; and a sine wave generating unit for providing a sine wave signal to the differential amplification unit in response to the output signal of the control unit, supplying a maximum current to the differential amplification unit while the touch panel is in a standby state, and controlling the level of the sine wave signal in response to conductivity of the object when the object touches the touch panel.

Abstract: A touch panel for a display device integrates functionality provided by resistive-type and EM-type touch panels. The touch panel is integrated with the display device and includes a resisitve-type touch panel arranged above the display device and an EM-type touch panel arranged below the display device.

Abstract: Techniques for identifying and discriminating between different input patterns to a multi-touch touch-screen device are described. By way of example, large objects hovering a short distance from the touch-surface (e.g., a cheek, thigh or chest) may be identified and distinguished from physical contacts to the surface. In addition, rough contacts due to, for example, ears and earlobes, may be similarly identified and distinguished from contacts due to fingers, thumbs, palms and finger clasps.

Abstract: A coordinate input device is provided. The coordinate input device includes a first input device for detecting a position input and obtaining a first input value indicate of the position, a second input device for detecting the position input and obtaining a second input value indicative of the position, the second input value having a tendency to be a more accurate indication of the position than the first input value, a determining unit configured to determine whether the first input device and the second input device simultaneously obtain the first input value and the second input value, respectively, a storing unit configured to store a relationship between the first input value from the first input device and the second input value from the second input device as correction information, and a correcting unit configured to correct the first input value on the basis of the correction information.

Abstract: A circuit configuration for a capacitive touch switch contains at least one sensor circuit with a capacitive sensor element which changes its capacitance value when touched, and an evaluation circuit which is supplied with an output signal from the sensor circuit in order to determine whether the capacitive sensor element is actuated or not. The at least one sensor circuit has a capacitance which is connected in parallel with the capacitive sensor element, and a capacitance/frequency converter which is connected to the parallel circuit containing the capacitance and the capacitive sensor element and generates, at its output, a frequency signal whose frequency depends on the total capacitance of the parallel circuit containing the capacitance and the capacitive sensor element. The evaluation circuit may thus use a significant change in the frequency of the output signal from the sensor circuit to deduce, in a simple manner, that the capacitive sensor element has been touched.

Abstract: A method of determining a type of touch plane operator input device comprises sensing the impedance across first and second terminals of a touch plane operator input device to distinguish the touch plane operator input device as being one of at least two different types of touch plane operator input devices. A method of processing an input from a touch plane operator input device comprises determining a first location of a first touch on the touch plane operator input device; determining a second location of a second touch on the touch plane operator input device; comparing the first and second locations to obtain an indication of an amount of difference between the first and second locations; and determining whether the indication of the amount of difference exceeds a predetermined amount. These steps are performed by discrete logic circuitry that provides an event notification to a microprocessor when the indication of the amount of difference exceeds the predetermined amount.