Recently (1 week ago) we received an email from the coach of the “Giant Sticky Notes” an FLL team in Newton, MA. They were having problems with reading the colors on the mat with light sensors, despite having multiple years of FLL experience. Their NXT could only identify light sensor values in a range from 40 to 60. They thought that because we were an experienced FLL and FTC team we could help solve their sensor problems in time for the qualifier the next day. Three of us (Josh, Chris Ben O) got a ride from Josh’s dad to Newton. We tried updating the firmware, recalibrating the sensors, making our own calibration program, and none of these solved the issue. After about an hour of thinking and fiddling, we discovered that the problem was within the “view” program that comes with the NXT. We figured this out by trying our own NXT out and getting the same results. We made a program in NXT-G to display the raw sensor value along with the calibrated sensor value and both values were correct! Be warned, FLL and FTC teams: the view program (even with RobotC firmware) may not be accurate under certain lighting conditions. If your view program is displaying odd values after calibration and the brick and sensors are not the issue, try writing your own program to display the values. If your team needs help or would like some advice, contact us and we can troubleshoot together to resolve the issue.