The basic idea is to make a very primitive "motion tracker" using simple IR phototransistors.
Of course, it will basically just rotate until both sensors have relatively equal readings. What will keep it from being jittery, is defining a deadband in the code. Other than that, it basically does a +1 or -1 left or right..
I am not using PWM, just calling out, or calculating out the angle of the servo 0-180 degrees using the Arduino library.
I will share code here after I do a test with the sensors mounted on the 1st servo.