Battery operated ink capture device that operates in a normal power mode during active use and a minimum power mode during absence of active use

摘要

A handwriting capture system includes a portable electronic tablet that capture pen strokes made on a standard pad of paper and transfer the captured pen strokes to a digital image capture device such as a personal data assistant or PDA using infrared communications circuitry. The portable electronic tablet is battery powered, and the handwriting capture system includes an infrared activated power switch to extend the useful lifetime of the battery by power up the electronic tablet and infrared communications circuitry only when the system is in use and otherwise by powering off the electronic tablet and much of the communications circuitry, in a manner that is entirely transparent to the user. An IR activity detector remains powered up when the system generally is powered off, and also furnishes power to at least the receiver section of the IR transceiver. When infrared activity occurs, the receiver section indicates that a signal has been received and the IR activity detector responds by signaling a switched power supply to apply normal operating power to the system.