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Vacuum cleaner with a microprocessor-based dirt detection circuit

  • US 6,571,422 B1
  • Filed: 08/01/2000
  • Issued: 06/03/2003
  • Est. Priority Date: 08/01/2000
  • Status: Expired due to Term
First Claim
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1. A vacuum cleaner having an operational status indicator arrangement, the vacuum cleaner having a motor fan assembly for generating an airstream originating at a suction nozzle for removing dirt particles from a surface, a dirt particle filtering and collecting arrangement, and at least one conduit fluidly connecting the motor fan assembly, the suction nozzle and the dirt filtering and collecting arrangement, the operational status indicator arrangement comprising:

  • at least one sensor for detecting an operational status of the vacuum cleaner;

    a microprocessor for receiving an input signal from said at least one sensor, comparing said input signal over a plurality of pre-determined time intervals to a threshold value, wherein said microprocessor has a pair of counters with corresponding maximum and minimum values, with said first counter initially set to a maximum first counter value, and said second counter initially set to maximum second counter value, wherein said second counter is decremented each time said input signal exceeds said threshold value and a flag is set when said second counter reaches said minimum second counter value and said first counter is again set to said first counter maximum value when said second counter is decremented a successive number of times equal to the maximum second counter value; and

    at least one indicator carried by said vacuum cleaner for indicating an operational status of said vacuum cleaner;

    wherein said at least one indicator indicates the operational status when said flag is set.

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