Solar Tracker

[Billfred]

Originally Posted by Sh1ine

I am trying to design a solar tracker project for my POE class. I have found online a lot of information about hacking a servo and replace the pot for photo sensors. I want to make a bigger system using the same principles, and without programming. Has anyone ever made a simple solar tracker? How did you accomplish it? Would it be possible to run a motor off of a Jag and connect the photo sensors up to it directly without any programming?

Thanks for your input!

According to this NI-hosted document, the Jaguars still require an external signal whether using CAN or PWM. (Is it possible to hack the firmware? I don't know--but even if you could, you're still programming.)

Seems like you could program up a few Trinket boards to handle the necessary processing; they support up to three analog inputs and two PWM outputs (or two and three; one pin goes both ways). A couple extra wires won't kill them (just say "MAGIC HAPPENS HERE" in the diagram), and eight bucks won't kill you if they somehow kill the board.

[DonRotolo]

OK, so no CPU. Actually makes it harder.

Super-simple: A motor that runs at 1 RPD (Rev Per Day). Or at least a system that spins the whole assembly one revolution per day. Runs continuously. Once in a while you should re-set it to point at the sun, because nothing is perfect... (The issue is how to manage wiring to the fixed earth.)

Simple: Use a relay to run a very slow motor. Make an "eye" (see below) to detect the sun's position. Use an Op-Amp to detect when the sun has passed the "eye" and move the motor a little until it points at the sun again. Feedback loop!

Eye: Just a sensor at the bottom of a tube. More than one sensor, actually: One when aimed "right at" the sun, one when aimed "sun has moved". Maybe the 'right at' sensor is 'a little further' so the system moves less often. Like once every 30 minutes. Oh, and a timer of some type to reset to start after, say, 6 hours of darkness. Simple but effective.

More complex: Several sun sensors for an Eye, logic for movement even if there's no sun, reset timers, and so on. But now we would be better off with software control...

Jaguar? Way overkill, adds way too much complexity. If you don't want to use a relay and a very slow motor, then get an H-Bridge chip and use a variable duty cycle to control motor speed. Jaguars need too much love and affection to work well from a simple circuit.