Ncr Corporation

Christopher J Wittensoldner

Denis Michael Blanford

Paul Oliver Detwiler

John K Burkey

Barry M Mergenthaler

Robert Joseph Tom

Wilbur I Hilles

The useful life of a laser, such as a laser diode, is extended by causing the laser to operate only intermittently when continuous operation is not required. When such a laser diode is used in a scanner for scanning coded symbols, such as bar codes, in merchandise check-out operations, continuous operation is required only when a coded symbol is present in a target area. A sensing device is provided for sensing the transitions in light reflected back from the target area, and a counter is provided for counting the number of such transitions. Since a much larger number of transitions are sensed and counted when a coded symbol is being read than when no such symbol is present in the target area, this difference in number of transitions is used to distinguish between the two conditions and to cause the laser diode to be turned on for continuous operation only when a coded symbol is present in the target area to be read.

Apparatus and method for extending laser life by discontinuous operation

A bar code reader has the capability of reading a bar code symbol containing information for causing change in the volume of a speaker associated with said reader, as well as reading merchandise identification symbols commonly associated with items such as merchandise being checked out at a point of sale terminal. The apparatus for controlling the volume of the speaker includes a microprocessor, a digital-to-analog converter, an AC coupler, a reference amplifier, a peak-to-peak amplifier and a push-pull driver.

Volume control apparatus

A scanning system having a laser and a motor for spinning an optical mirror arrangement for sensing indicia such as bar codes is capable of turning off the laser and the motor during periods of extended inactivity in order to minimize wear of these components and to reduce the use of electricity. Changes in the ambient light level adjacent to the scanning system which are typical of human motion are detected and are used to produce an electrical signal which can be used to turn the laser and the motor back on.

Scanning system presence sensing apparatus and method

A scanning device having a laser, a motor for driving a mirror arrangement for moving the beam of the laser, and a microprocessor for control purposes is provided with a system for measuring and correcting fault conditions to meet laser safety requirements. Detection devices are provided for determining whether the laser is on or off, and whether the motor is running at or above a predetermined speed. If the laser is stuck in an on condition, then the motor is left running and an error is signalled. If the motor will not operate at or above the minimum speed, the laser is maintained in an off condition and an error is signalled.

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Cambridge, OH, United States of America

Christopher J Wittensoldner