KY-025 Reed Magnetic Switch Module

Description

KY-025 Reed Magnetic Switch Module

The KY-025 uses a reed switch that is activated when a magnetic field is applied. This module is suitable for proximity detection, security and contactless control applications.

Detailed specifications

• Operating voltage: 3.3–5 V DC
• Output: Digital (open/closed circuit)
• Dimensions: 22 × 15 × 7 mm
• Weight: 5 g
• Main components: Reed switch, LM393 comparator, sensitivity-adjustment potentiometer, LED and resistors

How it works

The reed switch on the KY-025 closes when a magnet is nearby, creating a closed circuit. The onboard comparator provides a digital output when the magnetic field exceeds the threshold adjusted with the potentiometer.

Applications

• Security and alarm systems
• Proximity detection for doors and windows
• Liquid-level sensors
• Contactless-control projects
• Interactive art installations

Pinout

The KY-025 module has three pins:

1. VCC: Power supply (3.3–5 V)
2. GND: Ground
3. D0: Digital output

How to use it

Connect the KY-025 reed module as follows:

1. VCC to 5 V on the Arduino
2. GND to GND on the Arduino
3. D0 to a digital pin (for example, D3) to read the digital values

Using it with an Arduino Uno

Basic Arduino code example

const int led = 13; // LED sur l'Arduino
const int digitalPin = 3; // Interface numérique du capteur Reed
int digitalVal; // Valeurs numériques


void setup() {
  pinMode(led, OUTPUT);
  pinMode(digitalPin, INPUT);
  Serial.begin(9600);
}


void loop() {
  // Lecture de l'interface numérique
  digitalVal = digitalRead(digitalPin);
  if (digitalVal == HIGH) {
    digitalWrite(led, HIGH);
    Serial.println("Magnet detected");
  } else {
    digitalWrite(led, LOW);
    Serial.println("No magnet");
  }
  delay(100);
}

What the code does: It reads the KY-025 digital output, turns on the Arduino LED when a magnetic field is detected, and displays the status in the serial monitor.

Components required for the basic example

• Arduino Uno
• KY-025 module
• Connecting wires

Basic code explained

1. Pin initialization: The LED pin is set as an output and the sensor pin as an input.
2. Reading and displaying data: The sensor’s digital value is read and displayed in the serial monitor. The LED turns on when a magnetic field is detected.

Basic wiring

• VCC (KY-025): 5 V (Arduino)
• GND (KY-025): GND (Arduino)
• D0 (KY-025): D3 (Arduino)

Advanced Arduino code example

#include <Wire.h>
#include <LiquidCrystal_I2C.h>


LiquidCrystal_I2C lcd(0x27, 16, 2);
const int led = 13;
const int digitalPin = 3;
int digitalVal;


void setup() {
  lcd.begin();
  lcd.backlight();
  pinMode(led, OUTPUT);
  pinMode(digitalPin, INPUT);
  Serial.begin(9600);
}


void loop() {
  digitalVal = digitalRead(digitalPin);
  if (digitalVal == HIGH) {
    digitalWrite(led, HIGH);
    lcd.setCursor(0, 0);
    lcd.print("Magnetic: YES ");
    Serial.println("Magnet detected");
  } else {
    digitalWrite(led, LOW);
    lcd.setCursor(0, 0);
    lcd.print("Magnetic: NO  ");
    Serial.println("No magnet");
  }
  delay(100);
}

What the code does: It reads the KY-025 digital output, displays it on an I2C LCD, controls the Arduino LED and reports the status in the serial monitor.

Components required for the advanced example

• Arduino Uno
• KY-025 module
• 1602 I2C LCD
• Connecting wires

Advanced code explained

1. Including libraries: #include <Wire.h> and #include <LiquidCrystal_I2C.h> add the libraries required for the LCD.
2. Initialization: Communication with the LCD and sensor is set up in setup().
3. Reading and displaying data: The digital value is read and displayed on the LCD. The LED turns on when a magnetic field is detected.

Advanced wiring

• VCC (KY-025): 5 V (Arduino)
• GND (KY-025): GND (Arduino)
• D0 (KY-025): D3 (Arduino)
• VCC (LCD): 5 V (Arduino)
• GND (LCD): GND (Arduino)
• SCL (LCD): A5 (Arduino)
• SDA (LCD): A4 (Arduino)

Installing the driver/library

To use the KY-025 module and LCD with Arduino, install the LiquidCrystal I2C library through the Arduino IDE:

1. Open the Arduino IDE: Make sure you are using a recent version.
2. Open the Library Manager: From the menu, choose Sketch → Include Library → Manage Libraries.
3. Search for “LiquidCrystal I2C”: Use the search box to find the library.
4. Install the library: Click Install to add it to your IDE.

Keywords: switch, magnetic, sensor, reed switch, KY-025, Arduino, magnetic detection, sensor module.