Here's a little solar tracker that I built. It uses two calculator(2v 20ma or so) solar panels to detect where the sun is and a simple circuit. The motor is a windscreen wiper motor. It's a bit too weak and will probably break after about 6months, but I'm pleased it works. Obviously it needs to be fixed to something otherwise it will get blown over. Heres a photo testing it, the panel should be turned round 180 degrees, but I was testing it and kept turning it to check it moved properly.Theres lots of room improvement to be made I think.
Heres the sensor. By default it moves west until the shrouded solar panel is pointing directly at the sun. At night it resets to the central position, so that the othe solar panel can detect the sun in nthe east and reverse the motor direction. It has the problem that it will keep reseting to the centre position on sunny/cloudy days wasting energy, it needs a delay before it will reset at night. The sensor is in a plastiv tub to make it watertight.
This is the centre switch in the circuit. It's a reed switch off an old cycle computer. I rotated it 90* after this photo as it wasn't specific enough.
This is the other switch that reverses the motor when it's pointing west at night.
Solar Tracker more photos
