The "Dual-Axis Solar Tracker" uses 4 LDRs to sense the difference in the light intensity from four directions. It then processes the signals in the microcontroller - Arduino Uno. Finally, 2 servos rotate the attached Solar Panel in two different axes, horizontal and vertical. This way, the Solar Panel can face the direction of maximum light intensity, thereby increasing the productivity.
YouTube Link: https://www.youtube.com/watch?v=OzR8PGGTb9I