It features two LDR's, a differential amplifier and a motor driver that drives two brushed DC motors. When light falls upon one of the LDR's, the motor on the opposite side of the robot is activated.
Special thanks to IEEE-CRCE for helping me out with the PCB.
http://www.youtube.com/watch?v=c1UixVesL7A&feature=youtu.be
Details
Differential Amp: LM358 Motor Driver: L293D Motors: I picked them out of my nephew's toy :P Battery: 9V