C-3, R-6 , I-1


Product ID: 17618 SKU: sen-17618 Categories: ,

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.


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 [0.6in x 1.4in]


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

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.


Use Tools > Serial Plotter on the Arduino IDE to visualize the values on the analog interface, use a magnet to trigger the switch.

KY-025 arduino serial plotter output



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