The paper describes Romulux, a mobile robot equipped with 3D LiDAR carrying an illuminance meter and dedicated to measure indoor lighting quantity. The aim is to check compliance with lighting standards in terms of level and uniformity. The general architecture of the robot using the Robot Operating System (ROS) is presented, and technical choices are explained according to the different constraints. The space localization of illuminance data is computed with Synchronous Localization And Mapping (SLAM) algorithms. Then measurements are compared to standards requirements and interpolated into a user-defined grid to generate a dense illuminance map. Two experiments, one in a sport hall and one in an ice rink, are presented and results are exposed. The paper will follow the workflow from designing a robot to a functional system able to generate illuminance maps, compare with standards and save energy in case of over lighting.