Modern lighting systems are based on LEDs. LED lighting system should be dimmable to get all the benefits of this system. The study of the dimming process and the efficiency of the LED luminary are of great importance in the development stage of device. For these purposes it is necessary to use special expensive light measurement equipment such as video photometers. This article is associated with looking for a solution of this problem at lower cost. The article examines the concept of the LED luminary evaluation stand consisting of a matrix of photodetectors. More in-depth considerations of low cost ambient light sensor provided for use in photodetectors are given. This paper is focused on data processing received from ambient light sensor. Description and the results of experiments are given at the end of the paper.