Interlink Electronics, Inc.

Wendell W Ritchey

Robert Matthew Martinelli

Mark C Pickett

John K Martinelli

Stuart J Yaniger

Leslie J Reading

John K Martnelli

A touchpad assembly and method for providing a signal to a computer indicative of the location and applied pressure of an object touching the touchpad assembly is provided. The touchpad assembly includes X and Y position and pressure sensitive semiconductor resistance sensor layers. The X and Y sensors have a pair of spaced apart X and Y conductive traces running across opposite ends such that a resistance RX connects the pair of X traces and a resistance RY connects the pair of Y traces. The X and Y sensors come into contact at a contact point when an object asserts a pressure on the touchpad. The contact point is connected to each trace by a variable pressure resistance RZ associated with the X and Y sensors and variable position resistances of the X and Y resistances. First and second pair of timing capacitors are connected to respective ones of the pairs of X and Y traces. A microprocessor controls and monitors charging time of the capacitors to determine the position and asserted pressure of the object touching the touchpad.

Force sensing semiconductive touchpad

Infrared communications scheme for an infrared transmitting device having a light emitting diode (LED) ramps up the power of a carrier frequency signal applied to the LED in a given time interval to a given value. The carrier frequency signal is then frequency modulated with a data message for transmission by the LED. The power of a DC signal applied to the LED may then be ramped up in a given time interval to a given value before the carrier frequency signal is modulated with a data message. After transmission of the data message, the power of the carrier frequency signal applied to the LED is ramped down in a given time interval to a given value. The power of the DC signal applied to the LED is then ramped down in a given time interval to a given value.

Infrared communications scheme

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Camarillo, CA, United States of America

Wendell W Ritchey