Abstract: An optical navigation sensor device and an image processing method using a 2-dimensional sequential image process are disclosed. A pre-processor stores digital voltage values of respective pixels of an image received from a pre-processor in a memory, performs a pre-process for the digital voltage values of respective pixels sequentially received from the memory, thereby producing a pre-processed current image, and extracts a pre-processed current central image from the pre-processed current image. A motion coordinate calculator stores the pre-processed current central image as X/Y-axis reference image candidates, determines replacement of X/Y-axis reference images for calculation of motion coordinate values of a next pre-processed image in accordance with X/Y-axis motions of the pre-processed current image, and compares the pre-processed current image with the X/Y-axis reference images, thereby calculating X/Y-axis motion coordinate values of the pre-processed current image.

Abstract: An optical mouse comprises a housing, an optics module, and a replaceable contaminant barrier. The housing has a surface with an optical window. The optics module includes a light source disposed within the housing and configured to direct light out of, and receive light in, through the optical window. The replaceable contaminant barrier is transparent and is removably secured across the optical window.

Abstract: Disclosed is a method for calculating a movement value of an optical mouse and an optical mouse using it. The method comprises the steps of: adjusting a reference frame update speed based on a movement speed of the optical mouse and updating the reference frame, calculating a first movement value, wherein the step of calculating the first movement value sets a reference area in the updated reference frame, and finds a correlation between a current input frame and the reference area of the reference frame to calculate the movement value, and resetting a reference area, wherein the step of resetting a reference area sets a new reference frame to which the reference area of the reference frame is moved by considering the calculated movement value according to the adjusted reference frame update speed.

Abstract: There is described a method of operating an optical motion sensing device comprising a light source and a photodetector device, the method comprising the steps of a) illuminating a surface portion with radiation by means of the light source, b) detecting radiation reflected from the illuminated surface portion by means of the photodetector device, c) detecting and measuring displacement with respect to the illuminated surface portion; and d) outputting motion reports that are each representative of a magnitude of the detected displacement, steps a) to d) defining a flash period and being repeated at a selected flash rate. The method further comprises the steps of e) comparing the magnitude of the detected displacement with a determined displacement threshold, and f) increasing or decreasing the flash rate if the magnitude of the detected displacement is respectively greater or lower than the displacement threshold. There is also described an optical motion sensing device implementing this method.

Abstract: A data input device for use with a tracking surface having light-scattering properties. The device comprises a coherent light source for projecting a coherent light beam onto the tracking surface to reflect a speckle pattern. A detector having a field of view detects and images the speckle pattern. The detector operates in a tracking mode when the field of view intersects the coherent light beam. The intersection of the coherent light beam and the field of view comprise a detection zone. Relative movement between the coherent light beam and the tracking surface within the detection zone between is detected in the tracking mode, based on the reflected speckle pattern. Relative movement between the coherent light beam and the tracking surface outside the detection zone is not detected. A controller responsive to the detector operates in the tracking mode for correlating the imaged laser speckle pattern to track the relative movement within the detection zone.

Abstract: There is described a method of post-processing and reporting detected displacement in an optical pointing device as well as a sensing device for an optical pointing device implementing this method. Displacement is detected and a first count representative of a magnitude of the detected displacement is accumulated in an associated accumulation unit, this first count representing the magnitude of the detected displacement at a first resolution (or detection resolution). The first count accumulated in the accumulation unit is processed to convert this first count into a report count representing the magnitude of the detected displacement at a second resolution (or reporting resolution) lower than the first resolution. This report count is then reported, for instance to a PC or an external controller. These operations are repeated to generate periodic motion reports at the second resolution.

Abstract: A low power tracking device and a method of use thereof is described. The method includes receiving first tracking information from a first tracking device and periodically determining accuracy of the first tracking information. A second tracking device is activated and used to acquire second tracking information when said determining indicates that the accuracy of the first tracking information is inadequate. The first tracking device is substantially lower power device that the second tracking device.

Abstract: A method to detect the movement of an image sensor according to captured images. An image region is captured from a first image. Then, a first corresponding region matching the first region is captured from a second image. A second image region is captured from the second image. Then, a second corresponding region matching the second captured image region is captured from the first image. Finally, the movement of the image sensor is determined according to the first region and the first corresponding region when a first relative distance between the first region and the first corresponding region is the same as a second relative distance of the second captured image region and the second corresponding region, but in the opposite direction.

Abstract: A coordinate input device comprising a wheel operable through rotation includes a plurality of rotating bodies disposed along a circumferential edge of the wheel for rotation and a rotating body rotating state detection means for detecting the rotating state of the rotating bodies.

Abstract: An optical sensor and method of using the same is provided for sensing relative movement between the sensor and a surface by detecting changes in optical features of light reflected from the surface. In one embodiment, the sensor includes a two dimensional array of photosensitive elements, the array including at least a first plurality of photosensitive elements arranged and coupled to sense a first combined movement along a first set of at least two non-parallel axes, and a second plurality of photosensitive elements arranged and coupled to sense a second combined movement along a second set of at least two non-parallel axes.

Abstract: A system and method of manufacturing directed to an attachment system for use in an optical device. The attachment system mechanically couples a light source to an illumination lens using an attachment device. The attachment device can be an auto-centering device for reducing positional errors in a light beam emitted from the light source.

Abstract: A finger-fitting pointing device is disclosed. There is at least one housing. Each housing can be fabricated from a flexible, glove-like material, and fits a finger of a user. A click sensor is disposed in the underside of each housing, and is actuated by the user pressing the underside of the housing with the inserted finger against an external surface. An optical sensor is also disposed within the surface of a housing, and detects relative movement of this surface against an external surface, as caused by relative movement of the user's finger.

Abstract: A computer input device includes a light guide that illuminates a target area for imaging so as to permit tracking relative motion of a surface. The light guide also directs light to a window that is externally visible to a user of the device when the device rests upon a supporting surface. In one form, the light guide includes an entrance surface that receives light from a light source, together with two separated channels. The light guide directs a portion of the light incident upon the entrance surface through a first channel to the target area. The light guide further directs a portion of the incident light through a second channel so as to illuminate the window.

Abstract: An apparatus for controlling the position of a screen pointer for an electronic device having a display screen includes a light source for illuminating an imaging surface, thereby generating reflected images. The apparatus includes a single chip for receiving the reflected images, generating digital representations of the reflected images, and generating a first set of movement data based on the digital representations of the reflected images. The first set of movement data is indicative of relative motion between the chip and the imaging surface. The single chip includes a serial interface for outputting motion data in a serial format based on the movement data.

Abstract: A data input device for use with a tracking surface having light-scattering properties with respect to the device. The device comprising a single laser having a modulated light beam. A beam splitter splits the modulated light beam into two light beams projected along separate paths toward the tracking surface. A portion of the light striking the tracking surface reflects back into a cavity of the single laser for self-mixing with the projected light, thereby altering first and second characteristics of the projected modulated light beam according to first and second directions associated with the tracking surface. A detector associated with the laser detects the altered first and second characteristics of the modulated light beam projected by the laser, and a controller responsive to the detector determines the relative movement of the tracking surface and data input device relative to one another as a function of the altered first and second characteristics detected by the detector.

Abstract: A method and system for enabling user interaction with computer software running in a computer system. The user is provided with an interface surface containing information relating to the computer software and including coded data indicative of at least one interactive element relating to the computer software. A sensing device in the form of an optically sensing stylus contains identifying data indicative of an identity of the user. When the user writes with the stylus, or uses it as a pointer, an operative end of the stylus is brought into contact with the interface surface. The sensing device senses indicating data indicative of the at least one interactive element using at least some of the coded data. The computer system receives the identifying data and the indicating data from the sensing device. The interactive element is identified in the computer system using the indicating data, and user data is identified using the identifying data.

Abstract: A method of enabling user interaction uses an interface surface which contains information relating to at least one drawing field. The interface surface includes coded data that is indicative of an identity of the interface and a plurality of reference points. A sensing device is provided which senses coded data when placed in an operative position relative to the interface surface, and uses this to generate indicating data indicative of the drawing field and data indicative of the sensing device's movement or position relative to the interface surface. The method includes having a computer system receive the data from the sensing device and use this to identify the drawing field and any movement of the sensing device within the field.

Abstract: An improved mouse structure has a cover and a base pivotally connected to the cover. The cover is an elliptically curved shell with two ends, and has a pivoting portion extending downwardly from one of the ends thereof as well as a hook formed on another end thereof. The base comprises a receiving portion formed on an end thereof for receiving the pivoting portion, an engaging seat formed on another end thereof, and an engaging hole formed in the engaging seat for engaging with the hook.

Abstract: An optical navigation system for determining movement relative to a navigation terrain includes a first source and a second source of optical radiation for illuminating the navigation terrain, the first source differing from the second source in at least one operating parameter. The system further includes means to select the first source and the second source independently based on decision criteria. The system further includes a detector for capturing patterns in the optical radiation subsequent to illuminating of the navigation terrain.

Abstract: An apparatus and method for electronic device control. The apparatus can include a first housing including a first housing face, a display coupled to the first housing face, a second housing pivotably attached to the first housing the second housing including a second housing face, the second housing face being configured to cover at least a portion of the first housing face. The apparatus can also include a housing orientation detection module coupled to the second housing, the housing orientation detection module configured to detect a position of the second housing relative to the first housing. The apparatus can additionally include a controller configured to display motion on the display based on the position detected by the housing orientation detection module. The second housing can be pivotably attached to the first housing along at least two axes of rotation.

Abstract: A display pointing device (10) includes a fingerprint sensing circuit (18) that optically senses, for example, a portion of a fingerprint or other skin texture, and a fingerprint movement detection circuit (20), operatively coupled to the fingerprint sensing circuit (18), that is operative to determine a direction of movement and a rate of movement of skin texture being sensed by the fingerprint sensing circuit (18) to produce pointing output data (24) for a display (12). The pointing output data (24) may be, for example, data representing a visual indication of a position on a display screen, such as a position of a cursor or of highlighted text, or any other suitable position indication. A method for providing pointing information for display includes sensing a fingerprint, determining a direction of movement and a rate of movement of the fingerprint and producing a pointing output for display based on a determined direction of movement and rate of movement of the sensed fingerprint.

Abstract: Thumb and finger guide structure for a computer mouse includes two guides, one located on either side of the mouse. One guide is designed to receive the user's thumb and the other is designed to receive the user's little finger. The structure of the present invention positions the user's thumb and little finger with the user's hand in an open relaxed position. The structure allows the mouse to be moved and lifted without gripping its lateral sides. According to one embodiment, the guide structure of the present invention is retro-fitted to an existing mouse by the use of a peel and stick adhesive. According to another embodiment, a computer mouse is provided with the guide structure integral to it and for replacing an existing mouse.

Abstract: A scrolling apparatus is disclosed that includes a rotatable scroll wheel and a sensor assembly coupled mechanically through a flexible cable. The sensor assembly has an encoder wheel that rotates in response to rotation of the scroll wheel. The rotational axis of the encoder wheel is axially displaced from the rotational axis of scroll wheel, and the diameter of the encoder wheel may be greater than the diameter of a conventional encoder wheel. The differences in diameter of the scroll wheel and encoder wheel may be utilized to provide the scrolling apparatus with relatively high resolution. In addition, the flexible cable permits the scroll wheel to be mounted within a tilting mechanism.

Abstract: A pen-type optical mouse device indicates a cursor position or inputs writing or a movement of the pen-type optical mouse. An aspect of the pen-type optical mouse is to calculate coordinate values of the mouse device in accordance with a movement of the pen-type optical mouse device. The pen-type optical device includes an image sensor on a side of the interior of a main body of pen-type the mouse device, thereby allowing the pen-type optical mouse device to be slim and easy to hold.

Abstract: A scrolling apparatus is disclosed that includes a rotatable scroll wheel and a sensor assembly coupled mechanically. The sensor assembly has an encoder wheel that rotates in response to rotation of the scroll wheel. The rotational axis of the encoder wheel is axially displaced from the rotational axis of scroll wheel, and concepts related to gearing may be utilized to increase the angular velocity of the encoder wheel in relation to the scroll wheel. In addition, the diameter of the encoder wheel may be greater than the diameter of a conventional encoder wheel. The gearing concepts and the differences in diameter of the scroll wheel and encoder wheel may be utilized alone or in combination to provide the scrolling apparatus with relatively high resolution.

Abstract: Disclosed is an optical mouse comprising an image sensor, consisted of a plurality of pixels, for outputting signals accumulated in a given time as a pixel unit, an A/D converter, an image data calculating a moving value of the optical mouse, a system controller for controlling a data flow with an external system, an average value calculator calculating an average value, and a pick-up state discriminator for generating a pick-up state signal. In addition, the optical mouse further comprises a fluorescent lamp state discriminator for discriminating whether the optical mouse is in a fluorescent lamp state and generating a fluorescent lamp state signal.

Abstract: A light projection method and apparatus for an optical mouse is provided. The light projection method and apparatus for an optical mouse comprises: provides a light projection apparatus and projects a light into the light projection apparatus to form a first light beam and a second light beam. The first light beam is vertically projected to a detection area of an image detection surface and the second light beam is slantwise projected to the detection area of the image detection surface. The first light beam allows the image detection unit of the optical mouse to exactly detect the image on the detection area. The second light beam makes the contrast between the concave and the convex of the detection area become more obvious and the ability of the image detection unit of the optical mouse to detect and identify the on the detection surface is effectively enhanced.

Abstract: There is described a method for measuring relative motion between an illuminated portion of a surface and an optical sensing device comprising a photodetector array including a plurality of rows and columns of pixels respectively aligned along first and second axes comprising essentially the steps of comparing at a first point in time light intensity between neighbouring pixels of the photodetector array and determining along each of the first and second axes, edge direction data from the detected first light intensity pattern, extracting edge inflection data from the edge direction data from the detected first light intensity pattern, comparing at a second point in time light intensity between neighbouring pixels and determining along each of said first and second axes, the edge direction data from the detected second light intensity pattern, extracting edge inflection data from the edge direction data from the detected second light intensity pattern.

Abstract: Disclosed herein is a method of processing data of an optical mouse. The method includes the steps of calculating a motion vector of the optical mouse through processing of digitally converted image pixel data in an Image Signal Processor (ISP) by sequentially overlapping a reference image of an n?1 th frame to a present image of an nth frame and determining a moving direction of the optical mouse using approximately equal parts in the reference and present images; and transmitting the calculated motion vector to a personal computer through an interface; wherein the ISP includes an X axis navigation engine for processing data on a reference image for the motion of an X axis direction among the processed image pixel data and a Y axis navigation engine for processing data on a reference image for the motion of a Y axis direction among the processed image pixel data.

Abstract: A pointing device of a computer having absolute and relative positioning capability is disclosed. In a mouse pointing device embodiment, the mouse is movable over a mouse pad having a surface having a plurality of uniquely coded positions. The mouse includes a mechanism to detect the position over which it has been moved, and conveys this information to the computer to which it is coupled. Specifically, the surface having a plurality of uniquely coded positions in one embodiment is a two-color gradient in which each color goes from maximum to minimum intensity level over an axis perpendicular to that of the other. The mechanism includes sensors to detect the intensity levels of the colors. In another embodiment, a joystick pointing device having absolute and relative positioning capability is disclosed.

Abstract: An optical mouse is operated on a work surface and includes at least one light emitter for emitting a light beam; a light receiver contained by a casing; a rolling ball arranged on the casing and opposite to the light receiver. The light beam has only one reflection by the rolling ball during an optical path thereof and then is detected by the light receiver. The rolling ball is made of transparent material and the distance thereof with the light receiver is adjustable to vary image resolution. The optical mouse can be turned over and placed on a notebook computer for using as a track ball.

Abstract: An improved optical mechanism of an optical mouse is disclosed. The improved optical mechanism is implemented inside the optical mouse and applies a layer of black coating or a surface processing to surface adjacent to photosensor surroundings to thus form an absorbing layer for absorbing reflecting light not directly projected to a photosensor, thereby advantageously receiving relatively high light points by the photosensor and increasing light-and-shade contrast, i.e., stressing the corresponding light as the light is directly projected to the photosensor and otherwise, the corresponding shade is stressed. Therefore, the performance on determining the mouse image is actually increased.

Abstract: A multi-directional input apparatus having a volume as a signal output in which the number of parts of the multi-directional input apparatus is reduced. Turning members 40A and 40B which are turned when an operating member 30 is operated are combined at right angles in a case 10. The turning members 40A and 40B are provided at their one ends with gears 44A and 44B. Straight-ahead sliders 80 and 80 are mounted on two crossing side surfaces of the case 10 along the side surfaces and a mounting board of the input apparatus.

Abstract: An imaging lens unit has an imaging lens and an integral holder for a light source such as a LED. The imaging lens unit can include a body portion, with the imaging lens being formed as an integral part of the body portion, together with a light source support fixture also formed as an integral part of the body portion. The support fixture supports a light source in a desired spatial relationship with respect to the imaging lens, and may have an opening for insertion of the light source into the support fixture along an installation axis. The fixture may be configured to prevent removal of the light source along substantially all other axes. The light source support fixture can be configured to support and retain the light source without additional cooperating structure. The invention further includes a computer mouse having an imaging lens unit with an integral light source support.

Abstract: An input device having a housing; a pointing device coupled with the housing having a plurality of buttons; a scrolling element coupled with the housing; and a module for detecting user input for operating the input device in at least a first mode and a second mode, where in the first mode, the input device operates as a tabletop computer pointing device, and where in the second mode, the input device operates as a hand-held presentation device used to control a computer-based presentation.

Abstract: The present invention is a method of optical tracking sensing using block matching to determine relative motion. The method includes three distinct means of compensating for non-uniform illumination: (1) a one-time calibration technique, (2) a real-time adaptive calibration technique, and (3) several alternative filtering methods. The system also includes a means of generating a prediction of the displacement of the sampled frame as compared to the reference frame. Finally, the method includes three cumulative checks to ensure that the correlation of the measured displacement vectors is good: (1) ensuring that “runner-up” matches are near the best match, (2) confirming that the predicted displacement is close to the measured displacement, and (3) block matching with a second reference frame.

Abstract: A method for determining the compatibility of a working surface with an optical mouse having an optical sensor including (a) using the optical sensor to sense the optical characteristics of the working surface, (b) using a judging circuit to judge the compatibility of the working surface with the optical mouse according to the optical characteristics sensed by the optical sensor, (c) using the judging circuit to generate a judging signal according to the result obtained in step (b).

Abstract: An optical apparatus. The optical apparatus is applied to an object surface, comprising a frame, a light emitting device and an optical sensor. The frame is disposed in the optical apparatus, having a first compartment and a second compartment, wherein the first compartment has a first opening and the second compartment has a second opening. The light emitting device is disposed in the first compartment, wherein light emitted from the light emitting device passes through the first opening and is reflected by the object surface outside the frame. The optical sensor is disposed in the second compartment to receive light reflected from the object surface passing through the second opening.

Abstract: A pointing device, which is capable of changing the appearance of a display, includes a housing made up of a cover and a base, a single spool cable receiver rotatably mounted to the housing, and a cable having a first end and a second end with the second end mounted to the cable receiver. The pointing device has a first mode with a first portion of the cable having a first length external to the pointing device and a second portion of the cable wound around the cable receiver. The pointing device also has a second mode with the first portion of the cable having a second length external to the pointing device less than the first length.

Abstract: An optical navigation sensor apparatus for an optical mouse includes an optical navigation sensor having an electronic chip, an aperture plate and an imaging lens integrated into a single package. The imaging lens includes a lens housing surrounding the aperture and providing a barrier to the entry of foreign matter into the aperture. In one form, the optical navigation sensor also includes a light emitting diode (LED) for illuminating a small area of a surface under the sensor and generating a reflected image that is detected by the electronic chip. In a sensor having an integral LED, an integral collimating lens is included for receiving light from the LED and focusing the light from the LED on the surface to be illuminated. The collimating lens is incorporated into a lens housing surrounding the LED and protecting the LED from exposure to foreign material.

Abstract: One embodiment relates to an optical displacement sensor for sensing transverse displacement of a data input device relative to a surface by determining displacement of optical features in a succession of frames. The sensor includes at least a coherent light source, illumination optics to illuminate a portion of the surface, imaging optics, and a first array of photosensitive elements having a periodic distance. The illuminator and the detector are configured to produce on the first array of photosensitive elements an intensity pattern of light reflected from the illuminated portion of the surface. The intensity pattern comprises a plurality of speckles having an average speckle diameter which is between one half and two times the periodic distance of the array.

Abstract: A method of determining a movement vector between two images is disclosed. The two images are sequentially taken by an optical mouse. The method comprises first calculating a directional correlation value for a plurality of directional shifts between the first image and the second image. The minimum directional correlation value is chosen and compared to a threshold value. If the minimum directional correlation value calculated is less than the threshold, identifying a movement vector associated with the minimum directional correlation value. However, if the minimum directional correlation value is not less than the threshold, the first and second images are compressed and the calculations are redone. The compression continues until a qualifying movement vector is identified.

Abstract: A pointing device having an illumination system, camera system, and positioning mechanism is disclosed. The illumination system illuminates a surface below a transparent plate having a constant thickness. The camera system records images of the illuminated surface. The positioning mechanism adjusts the relative position of the illumination with respect to the camera system. The relative position is determined by the constant thickness. The positioning mechanism has a first position corresponding to a predetermined value for the constant thickness and a second position corresponding to the constant thickness being zero. The positioning mechanism is operable by a user of the pointing device to compensate for different thicknesses of transparent plates.

Abstract: A rotary encoder includes a roller having substantially cylindrical shape, an inner shaft, a translucent cylindrical light guide shaft, a pair of holders, a light-emitting device, and a light-detecting device. The inner shaft is inserted and secured to a center hole of the roller, and has a slit at one end along a direction parallel to the axis thereof. The light guide shaft is inserted in the inner shaft so that one end of it is surrounded by the slit, and this guide has a first and second planes, and a first and second inclined planes. The first and second planes are formed on a lower side at both ends of the light guide shaft in parallel to the axis of the shaft. The first and second inclined planes are formed above the first and second planes at an angle of 45 degrees to the axis of the shaft, so that the two planes are substantially orthogonal to each other.

Abstract: A light guide includes at least two channels from which light is shined on a target area. The multiple channels disperse light across the target area more uniformly and with fewer dead or bright spots. The channels may be integral to one another, and may be molded. The light guide may further include an integral holder for supporting and aligning a LED light source to shine upon an entrance surface of the light guide. The entrance surface may also be formed as a collection lens. The channels may also be configured to direct light onto a target area at different angles. One or more of the channel faces from which light emanates may also be non-planar.

Abstract: Disclosed herein is a single integrated circuit for an optical mouse. The circuit includes an image pixel array for recognizing light and shadow of a surface under the optical mouse, an analog-to-digital converter for receiving analog signal from the image pixel array and converting analog data into digital data, a motion vector calculation unit for converting the digital data into one-bit data and calculating a motion vector, a motion vector process unit for accumulating motion vectors, correcting errors of the motion vectors, and accumulating moving distances of the optical mouse, a timing signal generator for generating control signals to control an overall operation of the circuit and operation signals pursuant to operation states of the circuit, an interface designed to transmit values processed by the process unit into a personal computer, and a transceiver for enabling one of a universal serial bus or an IBM personal system/2 in the interface.

Abstract: An apparatus for controlling the position of a screen pointer for an electronic device having a display screen includes a light source for illuminating an imaging surface, thereby generating reflected images. An optical motion sensor generates digital images from the reflected images at a first frame rate. The motion sensor is configured to generate movement data based on the digital images. The movement data is indicative of relative motion between the imaging surface and the apparatus. The motion sensor is configured to modify the first frame rate to one of a plurality of alternate frame rates based on a current relative velocity between the imaging surface and the apparatus.

Abstract: A method of enabling user interaction with computer software executed in a computer system using an interface surface including information relating to the computer software. The interface surface includes a plurality of regions, each having coded data indicative of a plurality of reference points and an identity of the region. The user uses a sensing device to capture images of the coded data, identify and decode the coded data from the captured images, and then generate indicating data indicative of an identity of the region and movement or a position of the sensing device in the region. The computer system uses the indicating data to operate the computer software at least partly in accordance with instructions associated with the region.

Abstract: A pointing device is electrically connect to a computer. The pointing device is used to control movements of a cursor on a display device of the computer. The pointing device has a housing, a pointing unit installed inside the housing to generate pointing signals to control the movements of the cursor, a rollable device for generating rolling signals, a light source for illuminating the rollable device, and a control unit for controlling the pointing device. When the computer transmits a state signal to the pointing device, the control unit controls the light source to determine an illumination mode of the rollable device according to the state signal.

Abstract: A single-piece component rotatably supports a scroll wheel and includes an integral follower arm extending into a well within which the scroll wheel rotates. Formed on a circumferential surface of the scroll wheel are regularly spaced detents or other structures forming regularly spaced regions of alternating height. Located on an end of the follower arm is a follower which moves in and out of the detents as the scroll wheel rotates, with the arm biasing the follower against movement out of the detents. The carriage may also include pivots for relative movement of the carriage and scroll wheel assembly with respect to a housing, and a tab for actuating a switch.