In this paper, we propose energy-efficient automatic power controller which can power on and off the signboard at the specified light intensity using the Illuminance Detector. By using segmented section Classification algorithm, light intensity setup system propose variable resistor method which makes users more easy to control. Automatic light on-off system set a standard by measured illuminance data. Measured light-intensity through the Illuminance Detector are communicated with the signboard power controller with wireless communication, and it controls lighting system. In this paper, we evaluated the Energy-Efficient Automatic Power Controller of The Signboard using illuminance detector. Experimental results in lightless environment shows that the error rate is less than 3% by Accredited Testing Laboratories.