Before jumping into your first project, it helps to understand how the physical pieces connect together.

On this page you’ll learn:

• how the Arduino connects to your computer
• what the Arduino pins do
• how a breadboard routes electrical connections
• how jumper wires link everything together

Once you understand these basics, following project wiring diagrams will feel much more intuitive.

Connecting the Arduino to Your Computer (USB Cable)

(Photos USB to Arduino)

The USB cable serves two purposes:

• it powers the Arduino
• it allows your computer to upload code to it

Simply plug one end into your computer and the other into the Arduino.

When connected, you’ll usually see a small power light turn on.

This same cable is used every time you upload a project (called a sketch) from the Arduino IDE.

Arduino Pins (GPIO, Power, and Ground)

(Photos Arduino Pins)

Along the edges of the Arduino are metal pins where wires plug in.

These fall into three main categories:

Digital Pins

Used for:
• reading buttons and switches
• turning LEDs on and off
• controlling many modules

Analog Pins

Used for:
• reading sensor values like light or temperature
• measuring changing voltages

Power Pins

Used for:
• supplying 5V power
• ground (GND) connections

Most beginner projects use only a few of these pins at a time.

Each project guide on this site will tell you exactly which pins to use.

Breadboards (How Components Connect)

(Photos Breadboards How Connect)

A breadboard lets you build circuits without soldering.

Internally, the holes are connected in specific patterns:

• The long side rails run vertically and are connected top to bottom
• Each small center row of holes is connected horizontally
• The center gap separates the left and right halves

This means:

  • components in the same row are electrically connected
  • rows do not connect to each other
  • rails are commonly used for power and ground

The underside image helps make these invisible connections easier to understand.

Once you grasp this, wiring projects becomes much simpler.

Jumper Wires (Dupont Wires)

(Photos Jumper Wires)

Jumper wires are used to connect:

• Arduino pins to the breadboard
• components to power and ground
• components to input/output pins

For most projects on this site, you’ll primarily use male-to-male jumper wires.

They simply plug into:

  • Arduino pin headers
  • breadboard holes

Different colors help keep connections organized, but electrically they all work the same.

Putting It All Together

In a typical project:

• the Arduino supplies power
• jumper wires route that power and signals
• the breadboard connects components
• sensors send inputs to the Arduino
• the Arduino controls outputs

Once you understand this flow, every project becomes easier to follow.

Ready for Your First Project

Now that you know how the physical connections work, you’re ready to build something.

Next step: Choose a Beginner Project

Each project guide will show:

• where each wire goes
• which pins to use
• how to upload the code