How to Use a Push Button with Arduino: Beginner’s Guide

Introduction

In Arduino projects, push buttons perform various functions, like turning LEDs on and off, controlling motors, or initiating specific sequences. This guide introduces how to use push buttons with Arduino, covering how they work, wiring, and programming them to respond to presses. By the end of this article, you’ll easily incorporate push buttons into your projects and expand their functionality.

What is a Push Button?

A push button is a simple switch mechanism that controls electrical circuits. When pressed, it allows current to flow between its terminals, closing the circuit. Once released, the circuit opens, and the flow of current stops. In electronics, push buttons are widely used for manual input and controlling devices like calculators, computers, and household appliances.

Use Cases of Push Buttons

Push buttons control various functions in electronic and embedded systems. They commonly turn devices on or off, like power buttons on electronics, and frequently reset devices, such as computers and microcontroller boards. In interactive projects, push buttons provide user input to control actions like turning lights or motors on and off or initiating sequences. Push buttons also play a crucial role in control systems found in elevators, vending machines, and other interactive control panels.

How Push Button Works

Push buttons operate by either completing or breaking a circuit. There are two types of connections: normally open (NO) and normally closed (NC). In a normally open configuration, pressing the button completes the circuit, allowing current to flow. In a normally closed configuration, pressing the button breaks the circuit, stopping the current flow.

In Arduino projects, push buttons work in digital input mode. When pressed, they send a HIGH or LOW signal to the digital pin, which you can use to control actions like turning an LED on or off.

Turn the LED On and Off Using the Push Button

Let’s set up a simple project where pressing the push button toggles an LED on and off.

What You’ll Need:

• Arduino Board Uno
• Push button
• LED
• 220-ohm resistor (for the LED)
• 10k-ohm resistor (for pull-down configuration)
• Breadboard
• Jumper wires

Wiring Diagram

1. Connect the push button between a digital pin (pin 2) and ground (GND).
2. Connect a 10k-ohm pull-down resistor between the digital pin and the ground. This keeps the input signal low when the button is not pressed.
3. When the button is pressed, the circuit closes, sending a HIGH signal to the digital pin.
4. Connect the LED in series with a 220-ohm resistor to prevent too much current from flowing through the LED. The other leg of the LED should connect to a digital output pin (pin 13).

Pull-up vs. Pull-down Resistors

• A pull-up resistor keeps the input pin at a HIGH state when the button is not pressed.
• A pull-down resistor keeps the input pin at a LOW state when the button is not pressed.

For this project, we’ll use a pull-down resistor so that the pin reads LOW by default and goes HIGH when the button is pressed.

Arduino Code

Here’s a simple Arduino sketch to turn the LED on and off using a push button

// Pin assignments
const int buttonPin = 2;  // Push button connected to pin 2
const int ledPin = 13;    // LED connected to pin 13
   
int buttonState = 0;      // Variable to store the button state
   
void setup() {
  // Initialize the button pin as input
  pinMode(buttonPin, INPUT);
   
  // Initialize the LED pin as output
  pinMode(ledPin, OUTPUT);
}
  
void loop() {
  // Read the state of the button
  buttonState = digitalRead(buttonPin);
  
  // Check if the button is pressed
  if (buttonState == HIGH) {
    // Turn the LED on
    digitalWrite(ledPin, HIGH);
  } else {
    // Turn the LED off
    digitalWrite(ledPin, LOW);
  }
}  

Explanation of Code:

• pinMode(buttonPin, INPUT): This sets the button pin as an input to detect whether it’s pressed.
• pinMode(ledPin, OUTPUT): This sets the LED pin as an output so that it can be controlled (on/off).
• digitalRead(buttonPin): Reads the state of the button. If it’s pressed, the value will be HIGH; otherwise, it’s LOW.
• digitalWrite(ledPin, HIGH/LOW): Based on the button state, this command turns the LED on (HIGH) or off (LOW).

Conclusion

Push buttons are simple yet powerful components for user input in Arduino projects. In this tutorial, you learned how push buttons work, how to wire them with resistors (pull-up or pull-down), and how to control an LED using a button. This basic setup can be expanded for more complex projects, like creating menus or controlling multiple devices.

Future projects could involve adding debounce logic to ensure the button press is accurately detected or controlling multiple LEDs or even motors with push buttons.