Phototrope

In BEAM robotics, a Phototrope is a robot that reacts to light sources. Literally, "light turning," this term is generally (if somewhat inaccurately) applied to light-seeking robots. More accurately, phototropes can either seek (photophiles) or flee (photophobes) bright sources of light.

The simplest and most common form of phototrope is the photopopper -- many are as simple as to be essentially two solarrollers stuck together.

One mechanism for phototropism in robotics is implementation of a light sensor where a direct feedback system allows for interaction with the environment. The phototrope analyzes "shots" of its environment and decides whether to move into a certain area depending upon the light intensity.

Alternatively, photovoltaic cells may be used to provide both control and energy for a phototrope. Clever geometry in construction allows for current yielded by a photovoltaic cell to cause motion in the direction of (or away from) the most intense light source in the robots vicinity.