The reflectance sensors pictured above are used to approximate the location of the AEV while on the track. The wheels have a reflecting tape on one side which the reflectance sensors recognize each time the wheel completes a rotation. The Arduino system recognizes distance by a unit called marks. One mark is roughly .4875 inches. Reflectance sensors allow the vehicle to travel to specific locations based on program settings. Orientation of the sensors determine whether the system reads positive or negative distances.
[Note: The reflectance sensors picture above are only attached to the arm. Updated pictures will be place on the website when the arm is mounted to the AEV.]