It was basically used as a test bed for various circuit setups.

What Sanner had to do?
Follow a line on the floor ,provided that the line had a complement reflective property.[ie white line on a black floor or black line on a white floor].

Base of the machine
The base is was part of a toy truck I had stashed somewhere.The base had rubber caterpillar tracks which gave a good grip.The motors were heavily geared and was capable of carrying alot of weight.

Controller
Scanner was made when I didn't have a clue about microcontrollers.So my logical step was to use my PC's parallel port.I did the basic programming in "C".Later i made a simple GUI in Visual Basic,which showed live indications of the sensors triggering and the current movement of the machine.

Line DetectionThe machine used two Infra Red sensors to track the line.The algorith used was simple

• If both sensors are LOW,move FORWARD.
• If S1 is HIGH and S2 is LOW, STOP and turn LEFT [S1....Left Sensor, S2....Right Sensor].
• If S1 is LOW and S2 is HIGH, STOP and turn RIGHT.
• If both sensors are HIGH, STOP ,backtrace till any one sensor goes HIGH

Circuits/Sensors

I used a breadboard to check out my circuits as i said ,...scanner was a test machine.The circuit used for the sensors can be found in the "Circuit Boards" section.The motors were run through an H-bridge chip...The L293D.

Qusetions?If you got any questions.please feel free to message me.You can use the "Contact Me" page or mail me at gerryseq(at)rediffmail.com .