KY-021 Mini Reed Switch Module

Arduino magnetic reed switch module Keyes KY-021. A reed switch is a magnetic sensor that is normally open and gets closed when exposed to a magnetic field.

The KY-021 Mini Magnetic Reed Switch Module consists of a 10kΩ resistor and a small reed switch actuated by a magnetic field, commonly used in mechanical systems as proximity sensors. Compatible with popular electronic platforms like Arduino, Teensy and ESP8266.