The sun seeker searches the sun in the sky (the brightest spot). It scans the whole sky by rotating horizontally and raising the light sensor viewing angle every turn by 10 degrees. Whenever it finds a direction that is brighter than the previous brightest direction it remembers the current horizontal and vertical angle. After the whole sky has been searched, it move such that the light sensor points to the brightest spot. The light sensor is shielded a bit to reduce the viewing angle.

The seeker has a calibration program to determine the number of actuator rotations needed for a complete turn of the sensor. In the calibration mode the light sensor points at 110 degrees. At that angle the path of the touch sensor is obstructed at one point (second picture). After the first obstruction, it raises the touch sensor, moves on a bit, lowers it again and continues until it hits it again. From the angular difference it gets the number of rotations for one turn (~7).

We had some ideas for programs - Sun dial, moon follower, light distribution logger - but then we needed the parts for another project.