Skip to product information
1 of 1


KY-025 大磁簧模組 Reed Switch Module

KY-025 大磁簧模組 Reed Switch Module

Regular price HK$15.00
Regular price Sale price HK$15.00
Sale Sold out
View full details


KY-025 Reed Switch Module for Arduino is a small electrical switch operated by an applied magnetic field, commonly used as proximity sensor.

The module has both digital and analog outputs. A trimmer is used to calibrate the sensitivity of the sensor.

  • Arduino KY-025 Reed switch module

  • KY-025 reed switch module fritzing part


The KY-025 module consist of a 2x14mm normally open reed switch, a LM393 dual differential comparator, a 3296W-104 trimmer pontetiometer, six resistors and two LEDs. The board has an analog and a digital output.

Operating Voltage 3.3V to 5.5V
Board Dimensions 1.5cm x 3.6cm

Arduino KY-025 Connection Diagram

Connect the board's analog output (A0) to pin A0 on the Arduino and the digital output (D0) to pin 3. Connect the power line (+) and ground (G) to 5V and GND respectively.

KY-025 Arduino
A0 A0
+ 5V
D0 3
Arduino KY-025 connection diagramclick to enlarge

KY-025 Example Code

In this Arduino sketch we'll read values from both digital and analog interfaces on the KY-025, you'll need a magnet to interact with the module.

The digital interface will send a HIGH signal when a magnetic field is detected, turning on the LED on the Arduino (pin 13).

On the other hand, the analog interface will return a HIGH numeric value when there's no magnetic field present and it'll drop to zero when a magnet is near.

int led = 13; // define the LED pin
int digitalPin = 3; // KY-025 digital interface
int analogPin = A0; // KY-025 analog interface
int digitalVal; // digital readings
int analogVal; //analog readings

void setup()
  pinMode(led, OUTPUT);
  pinMode(digitalPin, INPUT);
  //pinMode(analogPin, OUTPUT);

void loop()
  // Read the digital interface
  digitalVal = digitalRead(digitalPin); 
  if(digitalVal == HIGH) // if magnetic field is detected
    digitalWrite(led, HIGH); // turn ON Arduino's LED
    digitalWrite(led, LOW); // turn OFF Arduino's LED

  // Read the analog interface
  analogVal = analogRead(analogPin); 
  Serial.println(analogVal); // print analog value to serial