Up to this point we have focused entirely on outputs, time to get our Arduino to listen, watch and feel. We’ll start with a simple pushbutton. Wiring up the pushbutton is simple. There is one component, the pull up resistor, that might seem out of place. This is included because an Arduino doesn’t sense the same way we do (ie button pressed, button unpressed). Instead it looks at the voltage on the pin and decides whether it is HIGH or LOW. The button is set up to pull the Arduino’s pin LOW when it is pressed, however, when the button is unpressed the voltage of the pin will float (causing occasional errors). To get the Arduino to reliably read the pin as HIGH when the button is unpressed, we add the pull up resistor.

Gather everything below before you start. This is your checklist — names, models, and versions only.

Here is what each component does and why it is part of this project.

A push button is a simple switch used to trigger an action in a device or process. Commonly found in homes and workplaces, it is often referred to as a pushbutton or push switch. There are two common types of pushbuttons.

A momentary pushbutton only maintains contact while it is being pressed, while a latching push button remains in its current state even if it is no longer pressed (image from pushbuttonsswitch.com). We will be using a momentary push button for this activity.

An LED, or light‑emitting diode, is an electronic component that produces light when current flows through it. As a semiconductor device, it emits light when electrons interact with the material inside. LEDs are available in many shapes, colors, and sizes (image from engineerfix.com). Unlike resistors, LEDs only work on one direction so make sure to connect each pin to its assigned terminal. The longer end is usually the anode which or the VCC pin, while the shorter end is the cathode or the GND pin.

A resistor is a passive device that restricts how easily electricity flows through a circuit. By adding resistance, it helps manage voltage levels, prevents excess current from damaging parts, and ensures each component receives the right amount of power. Each resistor is rated in ohms (Ω), and its value is usually shown with colored stripes printed on its body (image from ra-electronics.com).

Read the Code Breakdown section to understand what each part does.

Here is what each part of the code does. Read this after uploading.

Variable Declaration

const int buttonPin = 2;
const int ledPin = 13;
      

The difference of int and const int is that the int will change because it is a variable while the other one is a constant. We are taught by our math teachers about constant and variables. Constant are fixed no matter what you will do and Variables has an infinite number outcomes its value will depend on the equation.

The if else allows greater control over the flow of code than the basic if statement, by allowing multiple tests to be grouped together. An else clause (if at all exists) will be executed if the condition in the if statement results in false. The else can proceed another if test, so that multiple, mutually exclusive tests can be run at the same time.

Each test will proceed to the next one until a true test is encountered. When a true test is found, its associated block of code is run, and the program then skips to the line following the entire if/else construction. If no test proves to be true, the default else block is executed, if one is present, and sets the default behavior.

Note that an else if block may be used with or without a terminating else block and vice versa. An unlimited number of such else if branches is allowed.

This were explained in the Blinking LED.

On button off button:

int ledPin = 13;
int buttonPin = 3;
int buttonPin2 = 2;

void setup() {
  pinMpde(ledPin, OUTPUT);
  pinMode(buttonPin, INPUT);
  pinMode(buttonPin2, INPUT);
}
void loop() {
  if (digitalRead(buttonPin) == LOW) {
     digitalWrite(ledPin, LOW);
  }  else if (digitalRead(buttonPin2) == LOW) {
     digitalWrite(ledPin, HIGH);
}
      

Fade up and down:

int ledPin = 13; -----> int ledPin = 9;
      

const int buttonPin2 = 3;
int value = 0;
      

pinMode(buttonPin2, INPUT);
      

else if (digitalRead(buttonPin2) == LOW) { value++; }
value = constrain(value, 0, 255);
analogWrite(ledPin, value);
delay(10);
      

This project centers on exercises with momentary push buttons, guiding beginners through the process of wiring, coding, and experimenting with switches that directly control LEDs on the Arduino platform. By completing these activities, you gain hands‑on experience with how button presses translate into immediate visual feedback, learn to manage button states, and explore different ways to toggle or blink LEDs in response to user input.

• https://custommapposter.com/article/a-complete-guide-to-push-button-switches/1811#toc-0
• https://www.pushbuttonswitch.com/momentary-push-button-switch-guide/
• https://engineerfix.com/a-complete-guide-to-leds/
• https://ra-electronics.com/introduction-to-resistor-beginners-guide/

• Kevin Montenegro

Quality Checked By:

• Lemuel Jess Azaria
• Kyla Jade Entorum