In this activity, use an NXT car equipped with a light sensor to determine the hidden Morse Code message (under a table or in another room). The message will be determined using light sensor collected data on a pass over of the message.
See "Morse Code" PDF for detailed Instructions

In this activity, use an NXT car equipped with a light sensor to determine the hidden letter message (under a table or in another room). The letter will be determined using light sensor collected data on 3 passes over of the letter
See "Find The Hidden Letter" PDF for Detailed Instructions