NXT Line Follower

By jip
@ February 5, 2008

• Actuators / output devices: 2 MINDSTORMS NXT servo motors
• CPU: LEGO MINDSTORMS NXT
• Power source: NXT rechargeable battery
• Programming language: NXC (Not eXactly C)
• Sensors / input devices: 4 NXT Light sensors
• Target environment: indoor, DTU RoboCup

The robot measures line position with the 4 line sensors and feeds this to a PD-regulator which in turn produces the two motor outputs. This setup gives a smooth line following.

The cost of the robot is roughly the cost of a set of MINDSTORMS NXT + 3 additional NXT light sensors and the rechargeable battery.

The time to build includes several mutations of the basic design - time flies when you play with LEGO ;-). Of course some time was spent finding some usable values for the P and D constants for the PD-regulation.

I used the Bricxcc IDE for developing the controller program.