The SD-2 is a solar powered lightseeking
mechanism with only one motor.
Everytime the solar-engine triggers, the
motor briefly turns directing the robot
towards the light.
When it is facing the light, the motor is
moving left-right-left-right etc. in a
slightly chaotic fashion, making the
robot "hop" towards the light.
The electronics used in this mechanism
can also be used for a lightseeking head.