Hi everyone! I wanted to share my final year electronics project on PIC-Microcontroller. It is a simple light tracking device. The project theme to demonstrate the working of a Sun tracker using a PIC micro controller. The sun tracker solar panel has a controller interface that can adjust the angle of the panel in the direction of the highest incident radiation. I want to demonstrate this using a simple photo sensor that will move in the direction of a moving light source (can be a simple torchlight moved by hand). The components I have used are: 1)Photo sensor (phototransistors) 2)PIC microcontroller - 16F877 (has a built-in A/D conversion module) 3)unipolar stepper motor 4)ULN2003 (Darlington Transistor Array -for driving the stepper motor) Photo-Transistors are used as sensors for generating an analog voltage proportional to intensity of light falling on it. The PIC16F877 has a built-in Analog-to-Digital-Converter (ADC). The analog voltages from the Photo-transistors are given as Inputs to the Analog Port pins of the PIC. The Photo-transistors are mounted on the Shaft of the Stepper Motor. The Stepper Motor requires that its stator windings should be energized in a programmed sequence to cause the motor to run in a given direction with a required speed. The software includes the positioning of collectors through stepper motor & data acquisition and processing in the Microcontroller. I have written the code in MPLAB IDE. Here are the pictures of the PCB and the main working project. This the PCB inside the device. The soldering of components took about 2 days. http://i133.photobucket.com/albums/q71/reshma_b85/solarpro3.jpg This is the wooden box inside which the motor and the circuit has been placed. The sensors are mounted on the ring. This took the longest time to complete. http://i133.photobucket.com/albums/q71/reshma_b85/solarpro1.jpg http://i133.photobucket.com/albums/q71/reshma_b85/solarpro2.jpg Here is the video of the device in operation. Let me warn, the quality isn't that good since it was captured using my cell phone cam. I recommend watching it under low resolution. Feel free to comment and provide suggestions for improvement.