Arduino Breadboard LED Blink: Wiring, Code and Simulator

To build this Arduino Breadboard LED Blink project you need an Arduino Uno and a half breadboard, a 220 Ω resistor and a red LED. A resistor and an LED pushed into a half breadboard. The columns join their legs; two wires reach the board. Make the 2 connections in the wiring table, upload the Arduino C++ code, and drag the LED to another column: it goes dark, because its leg no longer shares a column with the resistor.

Open this circuit in the free Arduino Uno simulator

Parts list

Qty	Part	What it does
1	Arduino Uno	the microcontroller board
1	Half Breadboard	Push part legs into the holes: the five holes in a column are joined, and each rail along the edge is one wire.
1	220 Ω resistor	Limits current. 220 Ω in series with an LED; 10 kΩ as a pull-up or pull-down.
1	red LED	Lights when A (anode, the bent leg) is high and C (cathode) is low. Use a resistor.

Wiring

#	From	To
1	Arduino Uno pin 13	Half Breadboard 5t.e
2	Arduino Uno GND	Half Breadboard 10t.e

Step by step

Open the simulator. Open the BitForBytes Embedded Lab in your browser and start from the Arduino Uno. No install or account is needed.
Add the parts. Add a half breadboard, a 220 Ω resistor and a red LED from the parts palette.
Wire 1. Connect Arduino Uno pin 13 to Half Breadboard 5t.e.
Wire 2. Connect Arduino Uno GND to Half Breadboard 10t.e.
Paste the Arduino C++ code. Paste the Arduino C++ code below into the code editor.
Run it. Press Run. Drag the LED to another column: it goes dark, because its leg no longer shares a column with the resistor.

Arduino C++ code

// Breadboard blink: the resistor and LED sit in breadboard holes, and the
// breadboard's columns join them. Two wires go to the Arduino.
void setup() {
  pinMode(13, OUTPUT);
}

void loop() {
  digitalWrite(13, HIGH);
  delay(500);
  digitalWrite(13, LOW);
  delay(500);
}

What to try

Drag the LED to another column: it goes dark, because its leg no longer shares a column with the resistor.

Frequently asked questions

How do I wire the Breadboard LED Blink project on an Arduino Uno?

Make 2 connections: Arduino Uno pin 13 to Half Breadboard 5t.e; Arduino Uno GND to Half Breadboard 10t.e.

What parts do I need for this Arduino project?

An Arduino Uno and a half breadboard, a 220 Ω resistor and a red LED.

Can I simulate this Arduino project online for free?

Yes. The BitForBytes Embedded Lab runs this exact circuit and Arduino C++ code in your browser for free, with no install and no hardware. The sketch is compiled with the real Arduino toolchain and runs on an emulated ATmega328P.

What does the code do?

A resistor and an LED pushed into a half breadboard. The columns join their legs; two wires reach the board.