Abstract: A pointing device is provided for reporting motion information about the pointing device. Counts representing movement in two dimensions are processed so that a packet data stream may accommodate the motion information. One aspect of the invention utilizes the value of count to determine whether compression of the motion information should be performed. When it is determined that compression should be performed, a compression function is selected, the count is processed by the compression function, and an indicator is set to indicate that the count is processed by the compression function. Reporting information, which includes the processed count and the indicator, is then transmitted to computer system. A user input interface that is associated with the computer system recovers the counts using appropriate inverse functions in accordance with the indicators.

Abstract: Capacitive proximity sensing is carried out by detecting a relative change in the capacitance of a “scoop” capacitor formed by a conductor and a surrounding ground plane. Charge is transferred between the “scoop” capacitor and a relatively large “bucket” capacitor, and a voltage of the bucket capacitor is applied to an input threshold switch. A state transition (e.g., from low to high, or high to low) of the input threshold switch is detected and a value (TouchVal) indicative of a number of cycles of charge transfer required to reach the state transition is determined. The presence or absence of an object or body portion in close proximity to or contact with a device can be determined by comparing TouchVal with a predetermined threshold value (TouchOff).

Abstract: Interference between collocated wireless devices sharing the same RF channel is avoided or minimized by a new header format provided for the first data packet in an RF transmission. By inclusion of an invalid pulse in the header of each isolated data packet, an FM receiver that “captures” a desired signal from a closest device, midstream of processing an undesired signal (pertubation) from a more distant collocated device, is caused to abort the invalid packet and reinitialize. The receiver is then able to properly process the first packet in the desired transmission (from the closest device).

Abstract: An imaging compensation or transformation method for signals detected by a sensor which is placed arbitrarily away from its ideal location into signals which would result if the sensor were in the ideal location. This method links movement of the on-screen cursor to the movement of the ball by a user. The actual location of the sensor in the device can be at any necessary location relative to the other components of the device within the housing, and the necessary transformation functions can be calculated and applied to the signals. Enabling placement of the sensor at a location which is displaced from the ideal location provides degrees of design freedom to optimize ergonomic and aesthetic factors. The compensation or conversion method is a transformation which simulates the sensor being disposed at the ideal location regardless of where it is actually placed. This is done by defining a user vector space, a sensor vector space and a reported vector space.