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Method for detecting low battery voltage in portable scanning systems

  • US 4,967,188 A
  • Filed: 07/26/1989
  • Issued: 10/30/1990
  • Est. Priority Date: 07/26/1989
  • Status: Expired due to Term
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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