Programmable irrigation valve controller providing extended battery life

摘要

A battery powered irrigation valve controller designed to conserve the life of both the low voltage battery source which operates the microprocessor circuitry as well as the high voltage battery source which operates the external valve solenoids. Energy leakage from the high voltage battery source is prevented by maintaining the primary capacitor in a discharged state and delaying the charging of this capacitor until just before it is to be discharged to the valve solenoid. Unnecessary depletion of the high voltage battery source is also accomplished by isolating this source from the primary capacitor immediately prior to discharge, thereby avoiding a draw of energy from the high voltage battery source itself during discharge. The low voltage battery source which powers the computer circuitry is conserved through the action of the microprocessor which does not run in a continuous current consuming mode, but which remains dormant except for periodic sampling.