Push button

A momentary contact: HIGH while released, LOW while pressed — the first digital input.

Parts in the example:

LED
Button
Potentiometer

The Button block as it appears on the canvas.

What it is

A tactile switch closes a contact while you hold it. Wired between a GPIO and ground, with the chip's internal pull-up resistor on (pinMode(pin, INPUT_PULLUP)), the pin reads HIGH at rest and LOW while pressed. That inversion — “pressed is LOW” — trips up every beginner once.

In the simulator

The block is the button itself: press it with the mouse (or a finger, on a tablet) and hold. The Contact setting picks the kind: normally open (NA), the usual one, or normally closed (NF), which inverts the levels.

Pins

Pin	What it is
S	signal — to a GPIO configured as an input
GND	the other side of the contact — to a GND symbol

Wiring

The circuit below is the example Blink with button and potentiometer from the lab — open it with Project → Open example… and it comes ready to run.

Button pin	Goes to
S	D4 on the board (GPIO 4)
GND	a GND symbol

Settings

Double-click the block's title bar to open its card, then the Settings tab. Changes apply to the running simulation right away.

Setting	Accepts	Default	Notes
Contact	Normally open (NA) · Normally closed (NF)	Normally open (NA)	NA: HIGH when released, LOW when pressed. NF inverts it.

Code

sketch.cpp

#include <Arduino.h>

const int LED = 2;
const int BOTAO = 4;
const int POT = 34;

void setup() {
  Serial.begin(115200);
  pinMode(LED, OUTPUT);
  pinMode(BOTAO, INPUT_PULLUP);
  Serial.println("ready");
}

void loop() {
  // the potentiometer sets the blink speed
  int leitura = analogRead(POT);
  int intervalo = map(leitura, 0, 4095, 60, 1000);

  // while the button is held down the LED stays on
  if (digitalRead(BOTAO) == LOW) {
    digitalWrite(LED, HIGH);
    delay(100);
    return;
  }

  digitalWrite(LED, HIGH);
  delay(intervalo);
  digitalWrite(LED, LOW);
  delay(intervalo);
  Serial.printf("pot=%d interval=%d\n", leitura, intervalo);
}

pinMode(BOTAO, INPUT_PULLUP), then digitalRead(BOTAO) == LOW means pressed. In the example, holding the button keeps the LED on; released, the LED blinks at the speed set by the potentiometer.

Run it

Press Build and run. The first build of a project takes a while; after that, only what changed is rebuilt.

The simulation running: the canvas reacts and the serial monitor shows what the code prints.

Press and hold the button on the canvas: the LED stays on and the blinking stops. Release it and the blink resumes.

How the simulation models it

The block drives the level of its signal pin: HIGH at rest and LOW while pressed for a normally-open contact. The chip's pull-up resistor is not simulated — the block plays its part — so write INPUT_PULLUP in the code anyway: that is what makes the same sketch work on the bench.
There is no contact bounce. A real button bounces for a few milliseconds; the debounce your code should have will not be exercised here.
Reading the button before wiring S to a GPIO gives nothing: the message area tells you which pin is missing.

Try this

Count presses and print the count on every release — you will need to remember the previous reading.
Switch the contact to NF in Settings and see the readings invert without touching the code.
Add a second button that halves the blink interval while held.