Reed Sensor Module – Contactless Magnetic Detection for Arduino and Security Systemsh

Reliable Magnetic Switch with Low Power Consumption for Door, Window and Speed Detection

The Reed Sensor Module is a magnetic field detection module based on a reed switch (magnetic contact switch) that closes its contacts when a magnet is brought near. It outputs a digital signal (0 or 1) indicating the presence or absence of a magnetic field, making it ideal for microcontroller projects such as Arduino, ESP32, Raspberry Pi, and more.

 Key Features

• Operating Voltage: 3.3 V – 5 V DC – compatible with most digital logic systems.

• Digital Output (0/1): Switches when a magnetic field is detected.

• Reed Switch: Normally Open (NO) contact — closed only in the presence of a magnet.

• Easy Mounting: Bolt holes for secure installation.

• Compact PCB: Small module (~32 × 14 mm).

 Overview

A reed switch consists of two thin magnetic metal contacts sealed inside a small glass envelope. When a permanent magnet or other magnetic source comes close, the contacts attract and close, completing the circuit and producing a digital logic signal. When the magnet is removed, the contacts reopen and the signal changes back. This mechanism provides a non-contact, reliable magnetic sensing solution.

 Typical Uses

• Magnetic limit switches for motion systems like 3D printers and CNC machines.

• Security sensors for doors, windows, and access detection.

• Position sensing and counting of moving parts.

• Microcontroller project inputs and status signals.

• Home automation / IoT event triggers.

Reed is a dry reed pipe for short, is a kind of passive electronic switching element contacts, with a simple structure, small size easy to control, etc., which is generally a sealed enclosure glass tube are installed There are two elastic spring plate of iron, also called rhodium metal filling with inert gas. Normally, the two reed glass tube made of special materials are separated. When a magnetic substance near the glass tube under the action of the magnetic field lines of the two reed tube is magnetized to attract each other in contact spring will pull together to make a circuit node connected to the communication. External magnetic disappear after two reeds are separated because of their flexibility, the line also disconnected. Therefore, as a signal to control the use of a magnetic field line switching devices, reed can be used as a sensor for counting, limit, etc. (in the security system is mainly used for door sensor, magnetic window production), but also is widely used in a variety of communications devices. In practice, this is usually controlled by the permanent magnet is turned on or not two pieces of metal, it is also called “magnetron.”

1 Reed needs and with the use of magnets in magnetic induction to a certain time, will form a conduction state, the module output low, when there is no magnetic force, was disconnected state, the output high, reed and sensing distance beyond the magnet within 1.5cm of insensitivity or may no trigger phenomenon;

2 module DO output can be MCU I / O port is directly connected through the microcontroller can detect dry reed pipe trigger state;

3 output and relay module DO IN terminal connected to form a high-power reed switches, high voltage direct control.

With fixed bolt hole for easy installation

Working distance: 1.5 M

Operating voltage: 3.3 V-5 V

Output Type: Digital switching output (0 and 1)

Size: 3.2 x 1.9 x 0.7 cm

Net weight:4 g