I have gotten a ton of emails lately about how to follow a line with an NXT. I decided to build a bot to show off some of the easiest ways. Using twin light sensors and a LineLeader from Mindsensors, this robot shows 3 possible ways to complete that task. First, it can use a single light sensor and a simple threshold to follow the line. This method proves to be slow, but effective. Next it uses two light sensors to move forward and correct if one sees the black line. Finally comes the Mindsensors LineLeader which uses 8 light sensors and a control theory called PID to follow the line. As we add more light sensors and more complex control, the robot moves faster and more smoothly. Check out the bot and video below!