Reed Switch Magnetic Sensor Module Features & Specifications

Operating Voltage: 3.3V to 5V DC
Output format: Digital switching output ( 0 and 1 )
LEDs indicating output and power
PCB Size: 32mm x 14mm
LM393 based design
Easy to use with Microcontrollers or even with normal Digital/Analog IC
Small, cheap and easily available

Reed switch is a kind of passive electronic switching component with contacts with a simple structure, small size, and easy to control. It consists of a sealed glass envelope where there are two ferrous elastic reeds and is filled with an inert gas called rhodium. Normally, the two reeds are separated in the envelope. When a magnetic substance approaches the glass envelope, the reeds will come together due to the magnetic field thus completing an electric circuit. When the external magnetic field disappears, two reeds will be separated because of their elasticity, the circuit is also disconnected. Therefore, as a circuit switching device controlled by magnetic field signals, the reed switch can also be used as a sensor for counting and limiting, etc. (Applied in the security systems, mainly used for the production of door and window magnets), and it is also widely used in a variety of communications devices. In practice, it is common to use the two permanent magnets to control the connection of two metal sheets, thus it is also called a "magnetron".
The reed switch must work together with the magnet, when it detects magnetism, the circuit is connected and the module outputs a low level; when there is no magnetic force, it is disconnected and the module outputs a high level. If the sensing range of the reed to the magnet is more than 1.5cm, it will become insensitive and it may not be triggered;
DO output terminal on the module can be directly connected to I / O port of MCU, the trigger state of the reed switch can be detected through MCU;
DO output terminal on the module can be connected to the IN terminal on the relay to form a high-power reed switch for direct control of high voltage.

A reed switch is a sensor that closes the circuit in the presence of a magnetic field. Reed sensors can be used in many applications where contactless on/off is required. However, reed switches can be fragile to use directly, hence this module can make it easier to handle and mount the sensor in various applications.