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Auto Solar tracker Answered

Need a DIY plan for maintaining the most sun exposure for my solar panel projects. Saw one a few years ago using a bottle of propane gas. Anybody out there have any ideas?


I used some green ultra pure water clear 5mm LEDs driving some big assed (8 amps) matched Darlington transistors on a heatsink that I scrounged out of an old telex machine. Heck it even had some sweet stepper motors too.

I tried using some wide angle (120 degree) LEDs but their bandgap voltage was too low, 0.4 V instead of the 1.7V of the ultra green ones.

I got the circuit diagram from Redrock Energy , a very informative read. It was the LED5S5V Simplified low power tracker.

I've hooked the finished circuit up to a RC servo to test and was very happy with the results.
Alas I havent yet made anything to use the trackers on, but ...I'll be one of the first to know when the sun goes missing. :)

solar tracker.jpg

. The propane bottle trick is actually two bottles in one - there's a barrier in the middle. It is set up so that when the sun is shining on the middle of the "bottle" the forces are balanced. When the sun shines on just one side, the gas in that side expands and drives a cylinder to move the panel. . Just about any gas that expands well when heated (Freon, ammonia, etc) should work.

Ahhh .. .nifty trick. I must remember that one . . . .

You mean a solar panel that tracks the sun across the sky?

Yes . . . . it tracks the sun from east to west.

Well, there's an engineering way and an algorithm way.

The engineering way would be to have a motor with gearing that has a twelve hour cycle to track the panel that could be reset each morning.

The algorithmic way . . . You could use maybe three "snooted" LEDs as light sensors angled in three slightly different directions and compare the voltage output of them. Angle the solar panel towards the LED with the highest voltage and you should track pretty well (always some tweaking required, though).

You could even hook the LEDs up to power transistors and motors a la mousebot.

Does that help?