Arduino - Button value changes between 0 and 1 randomly

I used Arduino to read the state from a button. The reading state changes between 0 and 1 randomly and constantly. The belows are Arduino code and the wiring diagram

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#define BUTTON_PIN 7 void setup() { Serial.begin(9600); // initialize the button pin as a digital input pin pinMode(BUTTON_PIN, INPUT); } void loop() { // read the value of the button int buttonValue = digitalRead(BUTTON_PIN); Serial.println(buttonValue); }

Wiring Diagram

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The output on Serial Monitor

Newbiely | Arduino IDE 2.3.8

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File

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Sketch

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Arduino Uno

Newbiely.ino

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8 Serial.println("Hello World!");

Output

Serial Monitor

Message (Enter to send message to 'Arduino Uno' on 'COM15')

New Line

9600 baud

0 1 1 0 1 0 0

Ln 11, Col 1

Arduino Uno on COM15

2

How to solve it?

Your problem is known as the floating input problem. When you connect an Arduino pin to a button/switch without using any pull-up or pull-down resistor, this problem will happen.

How to solve

There are three way to solve it with Arduino:

• Use an external pull-down resistor on the Arduino pin ⇒ you need to modify the wiring diagram
• Use an external pull-up resistor on the Arduino pin ⇒ you need to modify the wiring diagram
• Use an internal pull-up resistor on the Arduino pin ⇒ you do NOT need to modify the wiring diagram, you just need to modify the code.

The below code used an internal pull-up resistor to solve the above problem

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