Project: Multiple LEDs on a Breadboard

Objectives and Overview

This project demonstrates one of the benefits of using a breadboard: the ability to add multiple and control multiple LEDs. You’ll work through a project where you add and control at least 3 LEDs to a breadboard.

Lesson Objectives

  • Using a breadboard and Arduino, control 3 or more LEDs.
  • Recognize and explain the role of the breadboard in this project.

Multiple LEDs on a Breadboard

Now that you’ve integrated a breadboard into your project, it’s time to level up and attach multiple LEDs!

When trying to work with multiple LEDs without a breadboard you may have encountered a key difficulty: How do you make the LEDs share a single GND pin on the Arduino?

This is one of the benefits of using a breadboard: You’re able to connect the power and ground pins of the Arduino the breadboard and therefore work with multiple components that effectively share the ground and power.

When you connect the power and ground pins of the Arduino the + and – rails on the breadboard, anything connected to those rails will be connected to the power or ground. For example, if you’re working on a project that needs three grounds, you’d connect the GND pin of the Arduino to the breadboard, and then the ground of each component to the – rail of the breadboard.

Activity: Multiple LEDs on a Breadboard


  1. Uno board and USB cable
  2. Breadboard
  3. Several jumper wires
  4. At least 3 LEDs
  5. 220 or 560 Ohm resistor for each LED


Check out this circuit diagram. Try to wire the project just by using the diagram. If you need more directions, the steps are listed below the image.

Fritzing diagram showing an Arduino and breadboard connection with multiple LEDs on it
  1. Connect a jumper wire from the GND pin of the Arduino to the – rail on the breadboard.
  2. Connect a jumper wire from the 5V pin of the Arduino to the + rail on the breadboard.
  3. Make sure to upload your modified Blink sketch to the board. Remember that you should include each LED pin you’re using!
  4. Plug your LEDs into any two rows on the breadboard with the long leg (positive) toward the top of the breadboard.
  5. Connect a jumper wire from the positive leg of each LED to the Arduino pins. In the example, pins 13, 12, and 8 are being used.
  6. Connect a jumper wire from the short leg (negative) of each LED to the – rail of the breadboard.

Common “Gotchas”

This is a great project for practicing connecting your Arduino code with the changes and additions that you make to the board and circuit.

Remember, each LED is going to need it’s own dedicated pinMode() and digitalWrite() or else it won’t work!

Additional Ideas

Once you’ve experimented with the challenge, here’s a project that you can try: Change the delay values in your code to see if you can program different patterns. Some fun ones to try would be to look up Morse code and see if you can create a multi-LED morse code message!

Additionally, try working with a neighbor to see if you can develop your own communication system. This may require pretty fine-tuned timing, but see if you can come up with a way to make your Arduinos “communicate” with each other.

This project challenge will require you to work with some additional resistors and you’ll have to tinker with the Arduino code. Once you complete it, you’ll have a much deeper understanding of these concepts!

Don’t feel like you’re bound to using red, yellow, and green LEDs! You should use three unique colored LEDs, but the colors that you select are up to you.