Don’t kick yourself in the nuts: Different types of hall effect sensors
Hall effect sensors are quite universal. At first, I thought they were only used for detecting RPM on spinning motors. There are actually three different types of hall effect sensors and it plays a critical role in which one to pick for your project.
Hall effect sensors are basically magnetic switches. The hall effect sensor will report the presence of a magnetic field. Depending on how and how long you want that presence known will decide on what hall effect sensor you decide to use.
The first type of hall effect sensor detects when a magnetic field is present, but only for a short period of time. Notice the yellow dot flashing ( representing the sensor ) and the red representing the magnets. Each time the sensor flashes yellow, that is the sensor acknowledging the magnet.
These types of sensors are common for a bike’s wheel hub to sense the speed of the bike or to measure the revolutions of your car’s engine.
The second type is the bipolar hall effect sensor. The sensor will trigger when a magnetic field gets close to the sensor. In order for the sensor to be triggered again, a magnetic field of the opposite polarity must come close to the sensor. This cycle repeats in a similar fashion to our first type
The third type of hall effect sensor is the proximity hall effect sensor. It detects the presence of a magnetic field but stays high ( or low depending on your sensor ) when the field is present. This is how door sensors work, a magnet on one side of the door in combination with the sensor on the other. When the two are close enough to each other the sensor will acknowledge it. Similarly, hall effect sensors have been used in keyboards to detect key presses instead of a tactile switch.