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Sensor system

  • US 4,936,333 A
  • Filed: 02/06/1989
  • Issued: 06/26/1990
  • Est. Priority Date: 02/06/1989
  • Status: Expired due to Term
First Claim
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1. In combination for controlling the opening and closing of a valve regulating the watering of a particular area in accordance with the amount of moisture in the area,a sensor for indicating the amount of moisture in the particular area,first means responsive to the indications from the sensor for producing a first signal having first characteristics during times with less than a particular amount of moisture in the particular area and having second characteristics during times with at least the particular amount of moisture in the particular area,a relay having first and second states of operation for operating the valve when the relay is in the first state of operation,means for providing an alternating signal,second means responsive to the alternating signal for normally providing a second signal periodically having first characteristics, andmeans connecting the relay in a circuit with the first means and the second means (a) for obtaining an operation of the relay in the second state during the time that the first signal has the second characteristics and the second signal periodically has the first characteristics and for obtaining an operation of the relay in the first state during the time that the first signal has the first characteristics or the second signal does not periodically have the first characteristics.

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