Magnetic Reed Switch Module KY-021

Description

What it is

The KY-021 Magnetic Reed Switch Module is a magnetic field sensitive device that changes state when activated by a magnetic field presence. It is commonly used in Arduino projects for automatic management and home automation.

Features

• Sensitive to magnetic fields
• Refined for Arduino projects and automatic counters

What it is for

The KY-021 module is ideal for creating simple alarm systems, automatic counters, or any application requiring magnetic field detection. It is compatible with Arduino and can be integrated into ESP32/ESP8266 projects.

Tutorial: How to use the Magnetic Reed Switch Module KY-021

The KY-021 Magnetic Reed Switch Module is a simple device that changes state when activated by a magnetic field. It is ideal for home automation and security projects, such as alarms or counters.

What you need

• Arduino Uno
• AAA Batteries (for the KY-021 module)
• USB Connection between Arduino and computer

Steps

1. Connect the VCC and GND pins of the KY-021 to the Arduino power supply voltage.
2. Connect the output of the KY-021 (OUT) to digital pin 2 of the Arduino.
3. Check the connection with a multimeter or an LED connected to a resistor to visualize the state of the output.
4. Write and upload an Arduino sketch that reads the input from the KY-021.
5. Approach a magnetometer to the KY-021 module to test its reaction.
6. Modify the code to send the switch state data to an online platform or an LCD display.

Example code

const int interruttorePin = 2;

void setup() {
  pinMode(interruttorePin, INPUT);
}

void loop() {
  if (digitalRead(interruttorePin) == HIGH) {
    Serial.println("Interruttore attivato");
  } else {
    Serial.println("Interruttore disattivato");
  }
}

Mini project

Create a simple alarm system that sends a notification when activated.

Common mistakes

• Incorrect connection of VCC and GND pins
• Insufficient power supply for the KY-021 module
• Missing magnetometer connection

Recommended accessories

• JST Connectors
• 330 Ohm Resistors
• 16×2 LCD Display
• Powerful Magnetometers

Frequently asked questions

Does the KY-021 work with Arduino?
Yes, the KY-021 is compatible with Arduino and other microcontrollers.

What types of magnets can I use?
Use powerful magnets like neodymium to activate the switch.

Can it be used without external power?
Check the datasheet, but it generally requires a power source.