Solar Tracker

A solar tracker is a device that is used to orient a solar panel towards the sun as it changes it's position in the sky over the period of daytime. A solar panel with a single axis is 30 percent more efficient than a  static panel and a dual axis tracker increases the efficiency by a further 4-8 percent.
The idea is simple. We have used two light sensors to determine the intensity of light in at two different points on the panel ( for a single axis tracker). To our convenience, we set these sensor LDRs, which are one amongst many others) at the extreme edges, i.e., the top and the bottom edges.
Now, as the sun moves in the sky, there is an increasing difference in the light flux on the two sensors. This difference can be detected directly by an analog window comparator or digitally by feeding the voltage levels across the sensors to a microcontroller (eg. Atmega 32). At this point, two cases arise:-
1) Positive difference (Sensor-1 has greater voltage than sensor-2)
2) Negative difference (Sensor-2 has greater difference than sensor-1)
If case-1 applicable, then the voltage comparator or the microcontroller will send a signal to forward drive switches of the motor direction control circuit. Similarly, if case-2 is applicable, a signal is sent to the reverse drive switches.
The control circuit is a H- bridge configuration motor supply. It consists of semiconductor switches like BJTs or MOSFETs. These switches are automatically operated when they receive a signal from the voltage comparator or microcontroller.
A slewing motor is preferred because of its slow speed and high torque. However, geared motors can be equally helpful.

More updates coming soon!