Digital Input With a Pushbutton With Arduino in Tinkercad

Click the “Code” button to open the code editor. Play the GIF above to see the program built in blocks.

Click on the Variables category in the code editor. Create a new variable called buttonState.

Drag out a “set” block.

We’ll store the state of our pushbutton to our variable buttonState. Click on the Input block category, drag out the the “read digital pin” block, and place it into the “set” block after the word “to”.

Since our pushbutton is connected to the Arduino on Pin 2, change the dropdown of the “read digital pin” block to 2. Now your blocks should read “set buttonState to read digital pin 2” which sets our buttonState variable to read our pushbutton state!

Click the Control category and drag out an if then/else block.

Configure it to evaluate whether buttonState is equal to HIGH using a Math comparator block. Drag out the Math comparator block into your if statement to check whether our variable buttonState is equal to HIGH.

We want to turn our LED on if the button is pressed – otherwise, we want our LED to be off. Under the Output block category, find the “set built-in LED to HIGH” block. Try adding two of these blocks to our if statement so that the LED will only be on when the pushbutton is pressed. set built-in LED should be HIGH when the buttonState is HIGH – otherwise, set built-in LED should be LOW.

Step 4: Pushbutton Arduino Code Explained

int buttonState = 0;

void setup()
{
  pinMode(2, INPUT);
  pinMode(13, OUTPUT);
}

void loop()
{
  // read the state of the pushbutton
  buttonState = digitalRead(2);
  // check if pushbutton is pressed. if it is, the
  // button state is HIGH
  if (buttonState == HIGH) {
    digitalWrite(13, HIGH);
  } else {
    digitalWrite(13, LOW);
  }
  delay(10); // Delay a little bit to improve simulation performance
}

When the code editor is open, you can click the dropdown menu on the left and select “Blocks + Text” to reveal the Arduino code generated by the code blocks. Follow along as we explore the code in more detail.

int buttonState = 0;

Before the setup(), we create a variable to store the current state of the button. It’s called int because it’s an integer, or any whole number.

void setup()
{
  pinMode(2, INPUT);
  pinMode(13, OUTPUT);
}

Inside the setup, pins are configured using the pinMode() function. Pin 2 is configured as an input, so we can “listen” to the electrical state of the pushbutton. Pin 13 is configured as an output to control the LED.

void loop()
{
  // read the state of the pushbutton
  buttonState = digitalRead(2);

Anything after a set of slashes // is a comment, just for us humans to read, and is not included in the program when the Arduino runs it. In the main loop, a function called digitalRead(); checks the state of pin 2 (which will be either 5V aka HIGH or ground aka LOW), and stores that state in the buttonState variable we created at the top.

  // check if pushbutton is pressed. if it is, the
  // button state is HIGH
  if (buttonState == HIGH) {
    digitalWrite(13, HIGH);
  } else {
    digitalWrite(13, LOW);
  }
  delay(10); // Delay a little bit to improve simulation performance
}

Below two more comment rows is an if statement that checks to see if buttonState is HIGH (== is a comparison operator, not to be confused with =, which is an assignment operator). If the condition is met, the built-in LED is set HIGH (on). If not, the code contained inside the else { is executed instead: the built-in LED is set LOW (off). If statements can exist alone, or with one or more else statements.

Step 5: Button Circuit Starter

Read more: Digital Input With a Pushbutton With Arduino in Tinkercad