The Wiltronic's 'wombat' Line Tracker Robot is a great project for schools and home! The buggy ‘tracks’ a line by measuring light differences reflected from respective surfaces. The LDR chip underneath the Line Tracker Robot chassis measures this light difference and communicates with IC Comparator. When less light is detected on one side of the tracker, the respective motor is activated. At the same time, the opposite motor is deactivated. As a result, the buggy swivels towards the surface with less light, which is the ‘line’. This results in a constant set of small zig zags, one motor driving then the other, the red LED’s on top of Circuit board indicating which motor is on.