Sensors are important in order to build working stuff
This kind of sensors use the quanto-mechanic phenomenon to signal the presence of a magnetic field
There are several kind of sensors
- latched: once it is triggered it latches and will not unlatch until a magnetic force of reverse polarity and strength is sensed.
- Bipolar sensors require a positive magnetic field (south pole) to operate them and a negative field (north pole) to release them while unipolar sensors require only a single magnetic south pole to both operate and release them as they move in and out of the magnetic field.