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). [Update: Aug 31, 2017. This has been in use for a year and it is reliable. I had another car battery go weak after five years, so I returned the ten year-old battery and kept the "new" dead car battery. It parks the solar rotator back to sunrise position reliably every night. I do not use wall adapter power for a year now. In this era, a microcontroller could be used instead of two ICs, but then you have to program the microcontroller (and commercially product test for radio wave output for a commercial product, I think redrok told me such).]
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.