Sun Tracker or Irrigation Timer to drive motors
ALL MY PROJECTS ARE HERE: http://www.opencircuits.com/User:Definitionofis
This is using two LEDs to sense the sun and send +- or -+ logic signals to a full bridge motor driver like L298 or http://www.redrok.com/led3xassm.htm LED3X schematic. I bought his. I recommend it.
I changed the front end logic to 4060 and 4011 ICs here, because I want to put the sun sensor separate from the controller board so it does not weather and die again, after 8 years of use. The circuit turns on a motor for 3 seconds once every 47 seconds to move the solar panels. You could use this circuit to turn on an irrigation motor for a very short time every several hours (just omit the sun sensor and select appropriate timing pins and much lower oscillation frequency for the 4060, since 3 seconds every 47 seconds is not long enough for irrigation).
I also made a simple trickle charger (below) and voltage-reduction circuit to power my motors and above circuit directly from the solar panels instead of plugging them into a wall outlet DC power supply. I am using an almost dead car battery.