Apparatus and method for controlling a watering system

An apparatus for controlling a first watering system, comprising:

• means for monitoring light and for converting the intensity of the light into a first voltage proportional to the light;
• means for monitoring humidity and for converting the level of the humidity into a second voltage proportional to the humidity;
• means for monitoring temperature and for determining when the temperature is below a first predetermined level;
• means for determining when the light intensity is below a second predetermined level;
• means for determining when the humidity is above a third predetermined level;
• first timer means, responsive to the plurality of said monitoring means and said determining means, for generating a triggering signal when a time-varying voltage reference level having a presettable maximum value exceeds each of the first and second voltages and each of the output voltages provided by said temperature monitoring and determining means, said light intensity determining means, and said humidity determining means;
• and
• second timer means, responsive to the triggering signal, for actuating the first watering system for a predetermined period of time.

A method of controlling a watering system, comprising the steps of:

• monitoring the ambient light intensity and generating a first electrical signal proportional thereto;
• monitoring the ambient humidity level and generating a second electrical signal proportional thereto;
• monitoring the ambient temperature and generating a third electrical signal when the temperature is below a predetermined cut-off value;
• comparing a time-varying reference voltage with the monitored light, humidity and temperature electrical signals;
• and
• actuating the watering system for a predetermined period of time when the magnitude of the time-varying reference level exceeds each of the first, second and third electrical signals.

An apparatus for automatically controlling a watering system, comprising:

• first ambient condition monitor means for sensing the magnitude of a first ambient condition and for converting the sensed magnitude of the first ambient condition into a first electrical signal;
• second ambient condition monitor means for sensing the magnitude of a second ambient condition and for converting the second ambient condition into a second electrical signal, said first and second ambient condition monitor means including variable modulating means for variably combining said first electrical signal and said second electrical signal to provide a modulation signal;
• first timer means for generating a triggering signal, said first timer means including:
• time-varying reference level means for providing a reference level electrical signal having a magnitude variable over time;
• comparing means for determining when the magnitude of said reference level electrical signal exceeds a value of said modulation signal and for generating said triggering signal in response thereto;
• and
• coupling means for coupling said modulation signal to said comparing means;
• second timer means, responsive to said triggering signal, for actuating the watering system for a predetermined period of time;
• and
• disabling means for comparing magnitudes of said first electrical signal and said second electrical signal with respective predetermined cut-off levels and for preventing said first timer means from generating said triggering signal when the magnitude of either said first or second electrical signal passes its respective cut-off level.

An apparatus for automatically controlling a watering system, comprising:

• light sensing means;
• first operation amplifier means having first input means and first output means;
• first connector means for connecting said light sensing means to said first input means of said first operational amplifier means;
• humidity sensing means;
• second operational amplifier means having second input means and second output means;
• second connector means for connecting said humidity sensing means to said second input means of said second operational amplifier means;
• first variable resistance means connected to said first output means of said first operational amplifier means;
• second variable resistance means connected to said second output means of said second operational amplifier means, said second variable resistance means also connected to said first variable resistance means so that a common connection therebetween is formed;
• third operational amplifier means having third input means and third output means;
• third connector means for connecting said common connection of said first and second variable resistance means to said third input means of said third operational amplifier means;
• time-varying reference level means, connected between said third input means and said third output means of said third operational amplifier means, for providing a reference level electrical signal having a magnitude variable over time;
• fourth operational amplifier means having fourth input means connected to said third output means of said third operational amplifier means and further having fourth output means connected to said time-varying reference level means;
• first variable resistor-capacitor network means connected between said fourth input means and said fourth output means of said fourth operational amplifier means;
• resistor network means connected between said fourth input means and said fourth output means of said operational amplifier means;
• and
• watering system switch means associated with said fourth output of said fourth operational amplifier means.