Method for detecting low battery voltage in portable scanning systems
First Claim
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1. A method of detecting battery voltages in a battery-powered scanning system capable of reading a bar code comprising the steps of:
- (a) moving a scanning element by a motor coupled thereto;
(b) producing a laser beam for focus upon and deflection by said scanning element, said laser beam thus being able to scan a bar code;
(c) driving said motor, and outputting signals from sensors coupled to said motor corresponding to scanning element movement;
(d) storing in memory, a value representing the motor speed which corresponds to a minimum battery voltage;
(e) during operation of the scanning system, measuring a motor speed derived from the signals output from said sensors and comparing it to the motor speed corresponding to said minimum battery voltage; and
(f) producing a user perceivable signal indicating unacceptably low battery voltage when said measured motor speed is below the motor speed corresponding to said minimum battery voltage.
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Abstract
A method for detecting low battery voltage in a hand-held scanner capable of reading the likes of a bar code measures the speed of the motor driving the scanning element and compares it to stored values. The stored values represent motor speeds directly corresponding to maximum and minimum battery voltages. The stored values can be introduced to the scanner for example, at the factory. If the motor speed is found to be lower than the speed corresponding to the minimum acceptable battery voltage, user understandable message is produced, which necessitates either battery re-charging or replacement.
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Citations
17 Claims
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1. A method of detecting battery voltages in a battery-powered scanning system capable of reading a bar code comprising the steps of:
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(a) moving a scanning element by a motor coupled thereto; (b) producing a laser beam for focus upon and deflection by said scanning element, said laser beam thus being able to scan a bar code; (c) driving said motor, and outputting signals from sensors coupled to said motor corresponding to scanning element movement; (d) storing in memory, a value representing the motor speed which corresponds to a minimum battery voltage; (e) during operation of the scanning system, measuring a motor speed derived from the signals output from said sensors and comparing it to the motor speed corresponding to said minimum battery voltage; and (f) producing a user perceivable signal indicating unacceptably low battery voltage when said measured motor speed is below the motor speed corresponding to said minimum battery voltage. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An apparatus for detecting battery voltages in a battery-powered scanning system capable of reading a bar code comprising:
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scanning means for scanning a bar code; a motor coupled to said scanning means for driving said scanning means; motor drive circuitry for driving said motor; memory for storing at least a value representing the motor speed corresponding to a minimum acceptable battery voltage; means for comparing actual motor speeds with the stored motor speed; and means for producing a user perceivable signal indicating unacceptably low battery voltage when said actual motor speed is below said stored motor speed. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17)
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Specification