we have had some problems with the light sensor we used for detecting the red cross. (Its of the new disciplin "Maze Entry" we created for beginners in Germany).
In the "list of the components" I have added a new link to an outbreak of the "TCS3200". I think it is a good performance to set S0 and S2 to GND and S1 and S3 to +5V.
We are now able to "see" white, black, metal and red.