Hall Effect Sensor is a sort of non-contacting position detector. They are either linear or removable and since they're non-contacting, they're free and have almost unlimited life.
In simple terms, hall effect sensors work whereby a magnet is centrally aligned with the Hall Sensor electronics. When the magnet is rotated the magnetic field changes and the electronics convert this into a relative positional output. In the case of a linear hall, the stroke is restricted due to this principle but the function is basically the same.
Hall Effect sensors are available with either an analogue or digital outputs depending on the application they are required for.
Although Hall Effect sensors are often seen as more expensive than standard Linear Sensor or rotary sensors this is not always necessarily the case and they are frequently selected because of their advantages;
They are suitable for harsh environments with high IP ratings to IP68/69K.
Hall Effect sensors do not wear so have a long life and in case of two part technology, meaning they have virtually unlimited life.
They are highly reliable.
Offer pre-programmable electrical angles and outputs.
Offer high speed operation.