Arduino - Switch

The ON/OFF switch, also called the toggle switch, has two state ON (closed) and OFF (open). The ON/OFF switch's state is toggle between ON/OFF each time it is presed, and the state is kept even when released. In this tutorial, we are going to learn how to use ON/OFF switch with Arduino.

Please do not confuse with the following:

Hardware Required

1	×	Arduino UNO or Genuino UNO
1	×	USB 2.0 cable type A/B
1	×	Wires
1	×	ON/OFF Square Switch
1	×	(Alternative) ON/OFF Round Switch
1	×	(Optional) Heat Shrink Tubing
1	×	(Optional) Soldering Iron
1	×	(Optional) 9V Power Adapter for Arduino
1	×	(Recommended) Screw Terminal Block Shield for Arduino Uno
1	×	(Optional) Transparent Acrylic Enclosure For Arduino Uno

Or you can buy the following sensor kits:

1	×	DIYables Sensor Kit (30 sensors/displays)
1	×	DIYables Sensor Kit (18 sensors/displays)

Please note: These are Amazon affiliate links. If you buy the components through these links, We will get a commission at no extra cost to you. We appreciate it.

About ON/OFF Switch

An ON/OFF Switch is a switch that changes its state (ON to OFF, or OFF to ON) once pressed, and then keeps that state even when released. To change the state, we need to press it again.

Pinout

The ON/OFF Switch basically has two types: two-pin switch and three-pin switch

In this tutorial, we will use two-pin switch. In this type, we do NOT need to distinguish between the two pins.

How It Works

There are two ways to use ON/OFF switch. The below is the wiring table for ON/OFF switch and the reading state on Arduino in both ways:

	pin 1	pin 2	Arduino Input Pin's State
1	GND	Arduino Input Pin (with pull-up)	HIGH ⇒ OFF, LOW ⇒ ON
2	VCC	Arduino Input Pin (with pull-down)	HIGH ⇒ ON, LOW ⇒ OFF

We only need to choose one of the above two ways. The rest of tutorial will use the first way.

Wiring Diagram

This image is created using Fritzing. Click to enlarge image

To make the wiring connection stable and firm, we recommend using Soldering Iron to solder wires and ON/OFF switch's pin together, and then use Heat Shrink Tube to make it safe.

Arduino Code - ON/OFF Switch

Just like a button, a ON/OFF switch also needs to be debounced (See more at Why needs debounce for the button, ON/OFF switch?). Debouncing make the code complicated. Fortunately, the ezButton library supports the debouncing functionm, The library also uses internal pull-up register. These make easy to us to program.

※ NOTE THAT:

There are two wide-used use cases:

The first: If the switch's state is ON, do something. If the input state is OFF, do another thing in reverse.
The second: If the switch's state is changed from ON to OFF (or OFF to ON), do something.

/* * Created by ArduinoGetStarted.com * * This example code is in the public domain * * Tutorial page: https://arduinogetstarted.com/tutorials/arduino-switch */ #include <ezButton.h> ezButton toggleSwitch(7); // create ezButton object that attach to pin 7; void setup() { Serial.begin(9600); toggleSwitch.setDebounceTime(50); // set debounce time to 50 milliseconds } void loop() { toggleSwitch.loop(); // MUST call the loop() function first if (toggleSwitch.isPressed()) Serial.println("The switch: OFF -> ON"); if (toggleSwitch.isReleased()) Serial.println("The switch: ON -> OFF"); int state = toggleSwitch.getState(); if (state == HIGH) Serial.println("The switch: OFF"); else Serial.println("The switch: ON"); }

Quick Steps

Do wiring as above wiring diagram
Connect Arduino to PC via USB cable
Open Arduino IDE
Install ezButton library. See How To
Select the right board and port
Click Upload button on Arduino IDE to upload code to Arduino
Press the switch to ON.
See the result on Serial Monitor.
Then press the switch to OFF.
See the result on Serial Monitor.

COM6

Send

The switch: OFF The switch: OFF The switch: OFF The switch: OFF -> ON The switch: ON The switch: ON The switch: ON The switch: ON The switch: ON The switch: ON The switch: ON -> OFF The switch: OFF The switch: OFF The switch: OFF

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Clear output

9600 baud

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