8LLF (Eight Legged Line Follower)


FASTEST TIME: 25.3 seconds


CONSTRUCTION: When I first started building this robot, I was going to use 6 legs and two 
light sensors. However, I soon realized that if I were to use 6 legs, I would have to use 
2 touch sensors to keep the legs in sync.  And if I were to use 2 touch sensors, I would 
either have to use 1 light sensor, because the RCX only has 3 sensor ports, or have a 
second RCX onboard.  Neither solution seemed very promising, so I decided to come up with 
a completely different design.  After spending a few more hours experimenting, I discovered 
that to get the robot to turn I would have to use 8 or more legs. That way at least 2 legs 
would be on the ground on each side of the robot at all times. 

     After I decided how many legs I would use, I began building.  Construction was much 
harder than I had expected, but as soon as I had the gearing all figured out, things went 
pretty smoothly.  When I tested the robot for the first time, I was only using 2 motors. 
The robot walked, but the motors really struggled when moving the robot.  The only way to 
gain more power was to add 2 more motors to help move the legs.  The 2 extra motors helped 
tremendously, and the robot walked (and turned) without a struggle. 

PROGRAMMING:  The program starts by turning motors A and C on. If at any time light sensor 
1 detects dark, motor a is put in reverse, turning the robot, thus putting it back on track.  
When light sensor 1 detects light again, motor A is put back in foward.  If light sensor 3 
detects dark, motor C is put in reverse, and when it detects light again, motor C is put 
back in foward. It is very simple, but works great!