This is the final version of the motor control. This version has the best voltage spread and the transistors can all be PNP power transistors. I used 2n3055 for this application.
The bottom potentiometer is used to set the center point, the two resistors were replaced with CDS cells. This might be used for many things where you want to control the direction of a motor with respect to another value.
I have bread boarded this and it works. When the CDS cells receive equal light the circuit is balanced, when one is shaded the circuit is unbalanced and polarity is shifted either positive our reversed.
You will not get positive and negative, rather positive and less positive.
