Sun Tracker Circuit Doesn't Work

I'm building a dual axis sun tracker. My solar panels are rated 10W. The solar panels is going to charge a 12V lead acid battery.

I tried the circuit below but didn't manage to get any good result.

Now, I 'm thinking of just using the 10mm Greed LED as photodiode and connect 4 of them(for dual axis), with 90deg between them, directly to my PIC18's ADC. I should use comparators but I think that the raw voltage data is more useful and I can record that as well to gauge the sun's brightness. The calculations will be done by the PIC and it will then move my stepper motor.

Is 7.5degree stepper ok for a sun tracker? I couldn't get high torque 1.8deg stepper. Half stepping or microstepping them probably can't be done since have a lack of time.

Hi, your circute is not going to work in this condition because Q5andQ6 collectors are conected to the base of Q2andQ4, cheak your circute.

7.5 degrees is a bit big but you can always gear it down to get smaller steps and higher torque.

Brian.

Here is a simple solar tracker, working, by using two circuits like that you can use it like a dual axis tracker

https://www.edaboard.com/threads/239792/