This paper demonstrates a self-powered Maximum Power Direction Tracking (MPDT) system capable of maximizing the energy harvesting by automatically adjusting the angle of the solar panel. The whole system is powered by a solar panel so no extra power supply is needed. The entire system consists of a solar panel, a motor, and a CMOS chip. A novel light direction sensor and the needed circuit are integrated in a single chip which is fabricated by a standard 0.5 mu m CMOS process. So it is small-size and low-cost. The system was tested to verify performance with different light direction and intensity. The results show that the system has good sensitivity to the incident angle and achieve tracking accuracy of +/- 1.8 degrees over a optical power range of 30-110 mW/cm(2). The presented system obtains an average output power gain of 18.4% over the fixed southwards mounted system under real weather conditions. (C) 2014 Elsevier Ltd. All rights reserved.