Published January 18, 2020 © CC BY-NC

Mini Reed Switch Module KY-021 on Arduino

Ever wondered on how security switches to detect doors and windows opening or closing work? Here is a simulation.

BeginnerProtip30 minutes1,943

Mini Reed Switch Module KY-021 on Arduino

Things used in this project

Hardware components

Arduino Nano V3.0 Compatible board

Solderless Breadboard

Jumper Wire Kit

Mini Reed Switch Module KY-021

Software apps and online services

Arduino IDE

Story

What we want to achieve

Using an Arduino - we are using a Nano V3.0 compatible board - we want to turn on the on-board LED (LED_BUILTIN) on when no magnetic field is present, simulating the way security switches on doors and windows work:

Attached to the door or window frame is a Reed Switch, on the movable part - the door or window - is magnet.

In closed position it will be near enough to the reed to close the circuit.When the door - or window - is opened, the reed will return to open position and the Arduino will trigger the LED - or any other operation - to alert of the door being opened.

Of course we can use only the Reed Switch, however the module makes it a bit easier.

Instead of triggering the LED_BUILTIN, you can trigger an external LED or other output devices, send messages, etc.

Note

Triggering a LED with the reed switch can be accomplished without the Arduino and we might give a tip on this later.

Requirements

Arduino (compatible) development board - we used the Arduino Nano compatible board (see here)
Our Mini Reed Module KY-021 (see here)
Arduino IDE (download here)

Restrictions

This tip is focused on using the Arduino IDE

How to

Wiring

KY-021   |  Arduino
PIN S    | D3
PIN +    | VCC 3.3V - 5V
PIN -    | GND

Code

Arduino code for Mini Reed Switch Module KY-021

//
// Reed Mini Module KY-021 for Arduino
// 18 January 2020 
// Author: dante@serveronthemove.com.au
//
// Hardware:
//   Arduino
//   Reed Mini Module KY-021
//
//   Wiring:
//     KY-021      -> Arduino
//      S          -> D3
//      + (middle) -> VCC 3.3V or 5V
//      - (GND)     -> GND
//
// Purpose:
//    A LED will be off and turn on LED_BUILTIN when magentic field is introduced, simulating an alert light when a door is opened.
//
// Note:
//    If you find the LED behaviour reversed - start turned on, and turn off when magnetic field is introduced -
//      you can reverse + and -


int reedModule = 3;    // S Pin of Reed Module KY-021 on Arduino D3

void setup() 
{
  pinMode (reedModule,  INPUT);
  pinMode (LED_BUILTIN, OUTPUT);
}

void loop()
{
  digitalWrite(LED_BUILTIN, digitalRead(reedModule)); // when the magnet is removed , turn LED on
}

Credits

SOTM

7 projects • 4 followers

Mini Reed Switch Module KY-021 on Arduino

Things used in this project

Hardware components

Software apps and online services

Story

What we want to achieve

Note

Requirements

Restrictions

How to

Wiring

Schematics

Schematic for Mini Reed Switch Module KY-021 on Arduino

Code

Arduino code for Mini Reed Switch Module KY-021

Credits

SOTM

Comments

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Mini Reed Switch Module KY-021 on Arduino

Mini Reed Switch Module KY-021 on Arduino

Things used in this project

Hardware components

Software apps and online services

Story

What we want to achieve

Note

Requirements

Restrictions

How to

Wiring

Schematics

Schematic for Mini Reed Switch Module KY-021 on Arduino

Code

Arduino code for Mini Reed Switch Module KY-021

Credits

SOTM

Comments

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