Lesson Template

Variables & Constants

Store values safely with clear names and const pins.

Progress

18% completed

Lesson Overview

This lesson introduces the core ideas behind Variables & Constants.

const int ledPin = 2;
int blinkDelay = 500;
bool isEnabled = true;

Learn how true/false values work and how they control LED and button states.

Learn how int stores whole numbers for counters, sensor readings, and timing values.

Learn how long stores larger whole numbers like millis() time values and larger counters.

Learn how unsigned int stores only positive whole numbers for counters and values that never go below zero.

Learn how unsigned long stores larger non-negative numbers for millis() timing and long-running counters.

Learn how char stores single characters like letters, numbers, and symbols in Arduino/ESP32 sketches.

Learn how to store text with String, create text using String(), and combine messages for Serial output.

Learn how float stores decimal numbers for sensor measurements, percentages, and calculations.

Learn how double stores decimal numbers and how it compares with float for precision-focused calculations.

Learn how short stores smaller whole numbers, when it can save memory, and how it compares with int.

Learn how word stores non-negative values, how it compares with unsigned int, and when it is useful for compact positive data.

Learn how arrays store multiple values of the same type and how indexing helps manage repeated data.