Line followers look simple, but they are the best cheap way to learn control.
Line followers look simple, but they are the best cheap way to learn control. The difference between a toy and a fast robot is not the chassis; it is sensor spacing, motor response and a PID loop that can recover after overshoot. A good build uses an array of 5-8 reflectance sensors instead of two crude IR modules.
The mechanical design is deliberately boring: two DC gear motors, one caster, battery centered over the axle and sensors mounted as low as possible.
The mechanical design is deliberately boring: two DC gear motors, one caster, battery centered over the axle and sensors mounted as low as possible. Keep the wheelbase short and the center of mass low. If the robot fishtails, reduce wheel diameter or move the battery forward before tuning firmware for hours.
Start with proportional control, add derivative once it can track curves, and add integral only if the robot has a consistent bias.
Start with proportional control, add derivative once it can track curves, and add integral only if the robot has a consistent bias. RoboHub can generate the first firmware scaffold, but you will tune constants on the actual floor because tape color, ambient light and motor mismatch all matter.