This project is going to guide you through making your very own light level detector, using cheap components and also providing compensation in the form of artificial light whenever the ambient light level in the room is low. Additionally, sensitivity adjustment can also be added for more precise systems.The sensor system can be used for a variety of applications such as an automatic stabilizer for light levels at home or at work, or you can just make one as a fun hobby or for a project.The circuit measures the surrounding light using the photodiodes.Photodiodes are connected in parallel for optimum performance,anode of the diodes is connected to the resistor and also to the analog input pin of the arduino board while the cathode is connected to the power supply.Light received by the diodes is given to the arduino in the form of an analog signal,this signal is processed by the inbuilt ADC of the arduino board. The processed signal is then calibrated to form data which maps to a suitable range.