초록 ▼

A system is disclosed comprised of several inputs in the soil that send a current into the soil and measure the resulting resistance in the soil. The soil resistance varies inversely with the level of moisture in the soil. Two voltage comparators are used to determine whether the soil has reached a

A system is disclosed comprised of several inputs in the soil that send a current into the soil and measure the resulting resistance in the soil. The soil resistance varies inversely with the level of moisture in the soil. Two voltage comparators are used to determine whether the soil has reached a pre-determined level of saturation or dryness. If the pre-determined level of dryness is exceeded, then a signal is sent through a switch and a latch, and activates the sprinkler solenoids. Once the pre-determined level of saturation is reached, a saturated signal is sent through the switch and latch in order to de-energize the solenoids. The system includes an over-watering prevention feature wherein a clock circuit is used so as to pulse the sprinklers in order to allow the water to permeate the soil between the sprinkler pulses.

대표청구항 ▼

An irrigation control device comprising: at least one sprinkler valve; at least one soil moisture sensor for measuring the level of moisture in the soil surrounding the sensor, the sensor being inserted into the soil in close proximity to the sprinkler valve; and circuit means responsive to the sens

An irrigation control device comprising: at least one sprinkler valve; at least one soil moisture sensor for measuring the level of moisture in the soil surrounding the sensor, the sensor being inserted into the soil in close proximity to the sprinkler valve; and circuit means responsive to the sensor for initiating at least one pulsed sprinkler cycle when the soil moisture sensor detects a low soil moisture level, and repeating the cycle until the sensor detects a saturated soil condition, and further wherein the pulsed sprinkler cycle is comprised of the activation of the sprinkler valve for a first predetermined time period, and a subsequent deactivation of the sprinkler valve for a second predetermined period of time; said circuit means further comprising means for applying current to the soil moisture sensor, means for measuring a resultant current from the moisture sensor, a current to voltage converter for converting the measured resultant current to a converted voltage, a dry threshold voltage comparator for comparing the converted voltage to a predetermined high voltage level, and producing a dry soil signal when the converted voltage is higher than the predetermined high voltage level, a saturated threshold voltage comparator for comparing the converted voltage to a predetermined low voltage level, and producing a saturated soil signal when the converted voltage is lower than the predetermined low voltage, and means for initiating the pulsed sprinkler cycle in response to the dry soil signal, and for terminating the pulsed sprinkler cycle in response to the saturated soil signal.