Introduction:
In this tutorial, we will learn about the KY-021 module, what is a read switch and we will build a simple project using the KY-021 module and an Arduino.
Mini Magnetic Reed Module KY-021:
The KY-021 Module will be our main component for this tutorial. This module has a mini reed switch mounted on a breakout board with a resistor. Figure 1 shows the module as seen in fritzing.
Pin Out:
The KY-021 module has three pins.
| Component Pin | Description |
|---|---|
| (-) | GND |
| middle | +5V |
| S | Signal |
What is a Reed Switch?
A reed switch is a type of switch that turns on and off when there is a strong magnetic field nearby.
Project:
Arduino Magnet Detector:
After learning about the KY-021 module and the reed switch, it is now time to build a project using the module. Our project will switch on the Arduino’s built-in LED if the KY-021 module detects a magnet.
Components:
For this project, we need the following components:
- Arduino Uno board (1 pc.)
- KY-021 Mini Magnetic Reed Module (1 pc.)
- Jumper wires
Wiring Diagram:
Figure 2 shows the connection between the Arduino Uno and the KY-021 Mini Magnetic Reed Module.
The KY-021 module pins are connected to the Arduino Uno board as follows:
| Component Pin | Description |
|---|---|
| (-) | GND |
| middle | +5V |
| S | Signal |
Code:
Below is the Arduino sketch for our project. I have added comments to explain important parts of the code. Save the code as KY-021.ino and upload it to your Arduino board.
// Arduino and KY-021 module
void setup() {
pinMode(8, INPUT); // module connected to pin 8
pinMode(13, OUTPUT); // built-in LED of arduino
}
void loop() {
if(digitalRead(8) == HIGH) digitalWrite(13, HIGH); // module activates, switch On the LED
else digitalWrite(13, LOW);
}
Project Test:
Apply power to your Arduino Uno board and bring a magnet near the reed switch. The LED should switch-on when the reed switch senses the magnet.
