Our final practical example in this chapter will illustrate the use of a Hall-effect sensor. Hall-effect sensors are simple components that detect the presence (or absence) of a magnetic field. In contrast to a PIR or distance sensor, you can use a Hall-effect sensor together with a magnet to monitor small-range – and even very rapid – movements. For example, you could attach a small magnet to the shaft of a DC motor and use a Hall-effect sensor to determine the motor's revolutions per minute.
Another common application of a Hall-effect sensor is in mobile phones and tablets. Some phone and tables covers and cases have a small magnet in them. As you open or close the case, your device detects the presence or absence of this magnet with a Hall-effect sensor and automatically turns on or off the display for you.
Hall-effect sensors come in three types, described as follows:
- Non-latching switch types (digital):...