Sensors are important in order to build working stuff

Hall Effect

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.

## Microphone

• Powering microphones