From BEAM Robotics Wiki
- A term used when referring to a type of robot capable of seeking and tracking the strongest source, of the type of stimulus that its sensors are intended to detecting.
A robot head seeks the stimulus it is designed to track by turning one way or the other, in an attempt to position its sensors so that they each detect an equal level of the stimulus. Once this is accomplished, most heads will remain stationary unless and until a new inequality in the stimulus is detected by the sensors. When this occurs, the head will track the stimulus by turning, in the direction of the greater level of stimulus, until equality is restored between the level of stimulus detected by both sensors. This turning action will be towards the side of the head upon which the sensor that is detecting the greater level of stimulus is mounted.
Robotic heads are very popular creations. Typically they are non-mobile stand-alone devices, the most common configuration being one that uses a pair of photo-sensors to detect and track the brightest source of light within the field of view of its sensors. There have also been a few heads created that exhibit phobic behavior. That is to say, rather than tracking the stimulus, the head will instead turn away from it.
Although single axis ( 1 degree of freedom ) heads are the most common type, 2-axis ( 2 degree of freedom ) heads have also been built. Despite the fact that 2-axis heads generally require twice as many parts to construct, they are usually not much more complex since they are controlled via 2 identical circuits, one for each axis of motion).
Head circuits and even complete Heads have been incorporated into larger robots, ( typically walkers ). When this is done, the head becomes a kind of active sensor, and provides some sort of signal or signals, which cause the robot it is part of, to turn and move towards the stimulus that the head is tracking.