Arduino Board Overview and Pinout

Arduino Uno Layout

The Arduino Uno is the most popular board. Let's understand its components:

Main Parts

Understanding the Pins

Digital Pins (0-13)

Digital pins can read or write two states: HIGH (5V) or LOW (0V).

• PWM Pins: Pins 3, 5, 6, 9, 10, 11 support PWM (Pulse Width Modulation)
• Serial Pins: Pin 0 (RX) and 1 (TX) for serial communication
• SPI Pins: Pin 11 (MOSI), 12 (MISO), 13 (SCK)

Analog Pins (A0-A5)

Analog pins read voltages from 0 to 5V with 10-bit resolution (0-1023 values).

Power Pins

Pin Mapping

digitalWrite(pin, HIGH)  -> Sets pin to 5V
digitalWrite(pin, LOW)   -> Sets pin to 0V
analogRead(pin)          -> Reads 0-1023 (0-5V)
analogWrite(pin, value)  -> PWM output 0-255

Built-in LED

Arduino Uno has a built-in LED connected to pin 13. This is useful for testing without external components.

Onboard Components

• Power LED: Lights when board has power
• TX/RX LEDs: Flash during serial communication
• LED on Pin 13: Programmable LED

Shields and Accessories

Shields are circuit boards that stack on top of Arduino:

Connecting Arduino

Via USB

Connect Arduino to your computer using a USB cable (Type-B for Uno, micro-USB for Nano).

Power Options

1. USB: 5V from computer 2. Barrel Jack: 7-12V adapter 3. Vin Pin: 7-12V from circuit

Warning: Never exceed 12V on the barrel jack or Vin pin!

Summary

Understanding the Arduino pinout is essential:

• Digital pins for on/off signals and PWM
• Analog pins for reading variable voltages
• Power pins to supply external components
• PWM pins for variable output (motors, LEDs)

Next Lesson

In the next lesson, you'll learn how to install the Arduino IDE on Windows.