Mario's Lego Robotics Archive


A light-follower developed together with my brother Giulio. This robot uses its rotating head to detect the strongest source of light and go that direction.


    While moving forward, the head continuously rotates left and right checking light value (multitasking).
  • The highest light intensity is stored in a variable together with its direction (directions are reduced to forward, left and right).
  • If maximum light is at left or right, the robot turns about 45 degrees accordingly.
  • When it bumps into an obstacle, it goes back a few seconds, stops and waits, while rotating its head, to see "the light" (forward direction excluded).

Requires three motors (left and right wheels, rotating head), two touch sensors (bumper and head position) and a light sensor.

S3 uses a bumper scheme that satisfies me very much. It employs a shock-absorber that normally keeps the touch sensor gently closed. When the bump occurs, the sensor immediately opens and detect it. The energy from the collision it is not released to the sensor itself but to the shock-absorber only.

Particular of the "normally closed" bumper.

The rotating head and the sensor which detects its position.

Wheels are coupled to work like tracks.

A motor makes the head turn through a worm gear.

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