HOW to Use Reed Switch Module on Raspberry Pi with ESP32

Overview

In this kit, there is a Keyestudio reed switch module, which mainly uses a MKA10110 green reed component.

The reed switch is the abbreviation of the dry reed switch. It is a passive electronic switch element with contacts.

It has the advantages of simple structure, small size and easy control.

Its shell is a sealed glass tube with two iron elastic reed electric plates.

In the experiment, we will determine whether there is a magnetic field near the module by reading the high and low level of the S terminal on the module; and, we display the test result in the shell.

Working Principle

In normal conditions, the glass tube in the two reeds made of special materials are separated. When a magnetic substance close to the glass tube, in the role of the magnetic field lines, the pipe within the two reeds are magnetized to attract each other in contact, the reed will suck together, so that the junction point of the connected circuit communication.

After the disappearance of the outer magnetic reed because of their flexibility and separate, the line is disconnected. The sensor uses this characteristic to build a circuit to convert magnetic field signal into high and low level signal.

Components

Connection Diagram

Test Code

//*************************************************************************************
/*
 * Filename    : Reed Switch
 * Description : Read the value of the reed sensor
 * Auther      : http://www.keyestudio.com
*/
int val = 0;
int reedPin = 15; //Define dry reed module signal pin connected to GPIO15
void setup() {
  Serial.begin(9600);//Set baud rate to 9600
  pinMode(reedPin, INPUT);//Set mode to input
}

void loop() {
  val = digitalRead(reedPin);//Read digital level
  Serial.print(val);//Serial port shows up

  if (val == 0) {//There's a magnetic field nearby
    Serial.print("        ");
    Serial.println("A magnetic  field");
    delay(100);
  }
  else {//There is no magnetic field
    Serial.print("        ");
    Serial.println("There is no magnetic field");
    delay(100);
  }
}
//*************************************************************************************

Test Result

Connect the wires according to the experimental wiring diagram, compile and upload the code to the ESP32. After uploading successfully，we will use a USB cable to power on，open the serial monitor and set the baud rate to 9600. We need to press the reset button on the ESP32, then the serial monitor will display the corresponding data and characters.

When the sensor detects a magnetic field, val is 0 and the red LED of the module lights up, “0 A magnetic field” will be displayed; when no magnetic field is detected, val is 1, and the LED on the module goes out, “1 There is no magnetic field” will be shown, as shown below.