Line Following

I have built many line following robots over the years, some good, some performing poorly. For some reasons, my robots were not fast enough to get me a good place on the podium. But my first robot built for a competition got me “People’s Choice Award”  for originality of the design. Of course, it wasn’t good at line following, I mean it wasn’t fast enough, but it did a decent job. Here it is:


The idea was to build a robot that balances on 2 wheels naturally, without the use of sensors. If one tilts the wheels outwards and places the center of gravity below the wheel axle, there is no way it will top over and it will stay statically balanced on just 2 wheels. Take a look at the pictures and see for yourselves:

LEGO CAR – one motor, one light sensor, RCX

I have “invented” a way to use one motor to follow a line. The mechanism involves the use of the differential, inverting the output direction of one wheel and the use of ratchets to block the wheel that would spin in reverse.  The motor will spin the differential’s case one way, that will make one wheel go forward and the other in reverse, until the sensor will be outside the line. Then, the motor will spin the differential case in the other direction, making the first wheel go in reverse and the other go forward, until the sensor is over the line again. The ratchets will allow only the wheel that spins forward to rotate, so the robot will zig-zag it’s way following the line nicely. Here are some pictures of it:

LEGO CAR – 2 motors, 3 sensors, Perseus microcontroller

I have built a faster line following car like robot using a custom microcontroller built by me. This time I used 2 motors and 3 sensors and the car performed better, but was still not fast enough to win anything. Here are some pictures of it:

ANT & INDY-CAR – 1+1 motors, one light sensor, RCX

I participated at a competition where 2 robots would run 3 laps on a greyscale circuit simulating a Indy 500 competition. The robots being practically line followers, I’ll show them here. I had 2 entries, Ant – a one motor, one sensor robot, and Indy-Car – a robot with a Ackerman steering, with the light sensor mounted on the direction swing bar. Ant was really popular and the slowest robot ever. But kids were so proud they beat Ant! Indy-Car was pretty good, getting in the middle of the pack. Here are the pictures from the event:

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