The Mixed Reality System is a unified system of real physical and fully simulated parts. When you see a mixed reality system for the first time, the big display is the first to appear. Even if the display has no influence on the game, it serves on the one hand as a playing field, as well as to give the viewers an insight into the simulated part of the world. The robots (Eco! BE2008) are responsible for the physical part of the system. In order for the robots to be able to interact with the simulated ball, their position must be determined. Each robot has a unique marker on its head. A camera films the playing field and the obtained image data are analyzed. The position of the markers is determined in the images. These are sent to the server. The server simulates not only the ball, but also all interactions with the ball, e.g. The collision between the robot and the ball. The positions of each robot and the ball are passed on to the clients by the server. The clients can use this data to send commands to the server. The commands are executed by the server directly, or they are sent via infrared to the robots.