of course the actual dc voltage value employed by the moisture sensor is not critical and a different set of components could result in a different voltage level being needed diode 103 is a rectifier providing dc pulses and capacitor 104 functions as a filter voltage regulator 105 provides a constant 6 volts at output terminal 106 substantially independently of input while the system described above has been discussed as a moisture sensor for soil and soil watering systems the principles of the invention could be employed in many situations where moisture content is an important characteristic if the moisture sensor of this invention is used specifically for trees as opposed to lawns it could be buried substantially deeper so that the moisture will penetrate to the deeper roots before the system turns off the watering function completely unrelated to providing water for plants the system could be modified to detect some aspect of the moisture content in a human body many other possibilities exist including the sensing of moisture content in concrete such as foundations or other structures large storage containers such as grain silos or other food stuff stored in bulk it should also be evident that the principles.