Hall sensor
Hall Effect Sensors (1mm magnet on the right) is based upon the “hall effect”, which is a way to detect the presence and intensity of a magnetic field. These sensors can be used to determine position, speed, - or really any form of magnetic field. A typical use would be in magnetic encoders which give robots positional feedback.
A reed switch is similar to a hall sensor in that it is used to detect the presence of a magnetic field, however a reed switch does not return the intensity of the field. Rather a reed switch is simply an on / off switch that is activated by the presence of a magnetic field. Such applications of a reed switch can be seen on home alarm window and door alarms.
Robots utilize hall sensors to detect the presence of a magnetic field for direction or locational positioning.
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