M5Stack Hall sensor

Hall effect unit. Three A3144E Hall sensor switches are integrated internally, processed by integrated circuits from the 74HC series. A low-level signal can be generated when the south pole of the magnet is near the top of the sensor or the north pole is near the back, and the internal LED indicator lights up. It is commonly used in applications such as door sensor alarms, proximity sensors, speed measurement, and more. The front side is the north pole, and a low level is output when the south pole signal of the magnetic field is detected.