More hardware problems

Yesterday everything seemed to work for us. We made a grid out of black isolationtape with yellow dots at the intersection. Yellow seemed to return the best value when light was reflected on it.
Then we got the communication between computer and NXT up and running. That means the NXT will stop and send a message if a yellow dot occurs or if the bumper is pressed. It then waits for a command from the computer.

Today the lightsensors all returned different values and had a hard time distinguish between the grey floor and the yellow dots. This could be because of the NXT is running low on battery but it could also be the change of ambient light. We now try a solution where the the line returns a value between the floor value and the intersection value.