Detection of Ambient Light Level for Control of Light Intensity without Positive Feedback

Dag A.H. Samuelsen and Olaf H. Graven


Continuous and Discrete Methodologies, Model Development, Controlled Illumination, nonlinear dynamic


Applying artificial illumination of indoor objects can in some situations be difficult, when a uniform illumination of the objects and their surroundings is required. This often comes as a result of large changes in the light intensity of natural sources of light, such as daylight. This can be regarded as a disturbance to the controlled light environment. The system presented in this paper allows for a simple, low cost solution which uses a special measurement algorithm in order to estimate the amount of ambient light falling onto an object or area. The measured amount of light emanating from controlled light sources is separated from the measured amount of light emanating from other, uncontrolled sources. The controlled light source can then be increased or decreased as desired in step with the changing surrounding light levels. This can be achieved without introducing positive feedback from the controlled light source or other instability problems due to interference between the control law and the surrounding light sources. The control structure allows the system to be integrated into a single unit with existing LED lighting products and thus does not require expensive or intrusive installation of extra photo sensors. The system is designed to operate autonomously, without user interaction at any time, aside from turning the lights on and off. The performance of the system has been verified by implementing the system and using it in both a laboratory and a real environment.

Important Links:

Go Back