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Build a Mini LED Lightsaber

Summary

Active Time
< 10 minutes
Total Project Time
< 10 minutes
Key Concepts
Circuits
Credits
Ben Finio, PhD, Science Buddies
Star Wars™ and lightsaber™ are registered trademarks of Lucasfilm Ltd.
DIY Mini LED Lightsaber

Introduction

Build your own mini LED lightsaber with a straw in this quick Star Wars-themed STEM activity. May the Force be with you!

This activity is not recommended for use as a science fair project. Good science fair projects have a stronger focus on controlling variables, taking accurate measurements, and analyzing data. To find a science fair project that is just right for you, browse our library of over 1,200 Science Fair Project Ideas or use the Topic Selection Wizard to get a personalized project recommendation.

Materials

 Materials to build mini LED lightsaber.

Prep Work

  1. Coin cell batteries are dangerous if swallowed. Keep them away from small children and pets.

Instructions

  1. Cut your straw into two pieces to form the blade and handle of your lightsaber.
    Scissors cutting a straw into two pieces.
  2. Pinch the legs of the LED so they squeeze the two faces of the battery. The long leg of the LED should touch the positive (+) side of the battery. The LED should light up. If it does not light up, you probably have the LED backwards. Try flipping it around.
     LED lighting up when leads are contacting battery
  3. Tape one of the LED legs to one side of the battery. Make sure there is a gap between the other side of the battery and the other leg, so the LED only turns on when you squeeze them together. Notice the gap in the picture.
    LED leg taped to one side of coin cell battery
  4. Press the battery and both LED legs into the shorter piece of straw (the handle). Be careful that the tape does not slide off the LED leg. It can help to use something (like the scissors or a pencil) to press the battery down into the straw. Press until the bottom of the LED is flush with the top of the straw.
     LED and battery being pressed into straw
  5. Squeeze the straw where the battery is, and the LED should light up.
    Squeezing the straw to light up the LED
  6. Slide the longer piece of straw (the blade) over the top of the LED.
    Connecting the longer and shorter pieces of straw
  7. Wrap the handle and connection between the two straw pieces in electrical tape.
    Handle wrapped in electrical tape
  8. Squeeze the handle to light up your mini LED lightsaber!
    Mini LED straw lightsaber

What Happened?

When you connected the LED to the battery, you made a very simple circuit. LEDs only let electricity flow through them in one direction, which is why they will not light up if you connect them backwards. Many times, circuits with LEDs require another part called a resistor, but you do not need a resistor when using a coin cell battery. See the Digging Deeper section to learn more.

Digging Deeper

Many electronics projects use breadboards for building circuits with LEDs, and the circuits in these projects frequently require AA, AAA, or 9V batteries. These batteries can provide a lot of electrical current—so much that they will quickly burn out the LED (or even cause it to explode!) if it is connected directly to the battery. To prevent this, we use an extra part called a resistor. It "resists" the flow of electrical current and limits the amount of current flowing, keeping it to safe levels for the LED.

Coin cell batteries cannot provide as much current as AA, AAA, or 9V batteries. They have a much higher internal resistance. This limits the amount of current that can flow, even when you connect an LED directly to the battery. This makes it safe to build a simple circuit without a separate resistor, making it convenient for you to build a compact circuit that fits directly into the handle of your lightsaber!

icon scientific method

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For Further Exploration

  • What is your favorite color lightsaber from the Star Wars series? Try making different-colored lightsabers using different-colored LEDs and straws. Time for a light-side vs. dark-side battle!
  • Try using two LEDs to build a dual-bladed lightsaber (Hint: you still only need to use one battery).

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