Building your own battery powered LED throwie is a fun electronics project that can be done quickly and cheaply. In this guide, I will show you step-by-step how to make one for under $5.

A throwie is a small LED device that can be thrown and will stick to surfaces when it lands thanks to embedded magnets. Throwies are popular for creating temporary light displays and public art projects.

Here is what you will need:


That's only about $3 worth of supplies! Now let's get building.

Step 1: Prepare the LED

The first step is to prepare the LED. Take your scissors and cut off the longer positive lead so both wires are the same length. This will make soldering easier later.

Use the needle nose pliers to bend the LED leads into a V shape. This will allow the LED sit upright when we attach it.

How to Build a Battery Powered LED Throwie for Under

Figure 1. Bend the LED leads into a V shape using pliers.

Step 2: Solder the Battery to the LED

Now it's time to solder the battery to the LED.

Put the LED down first with the leads facing up. Place the coin cell battery on top with the positive (+) side down so it connects to the positive lead of the LED.

Apply your soldering iron to heat up both the LED lead and battery terminal. Feed a small amount of solder so it melts and connects the battery and LED.

Repeat on the negative (-) side of the battery to the negative lead.

Soldering the battery to the LED

Figure 2. Solder the positive and negative terminals of the battery to the LED leads.

Make sure your solder joints are solid. Gently pull on the battery to verify it is firmly attached.

Step 3: Insulate with Tape

Now we need to add insulating tape to prevent shorts.

Cut off strips of the electrical tape and wrap it around each solder joint to fully cover any exposed metal.

It's a good idea to also run tape between the joints.

Insulated solder joints

Figure 3. Cover all solder joints with electrical tape to prevent shorts.

Step 4: Attach the Magnet

The magnet is what will allow your throwie to stick to metal surfaces when you toss it.

Take your strong neodymium magnet and stick it to the positive (+) side of the battery.

Now wrap tape around it to hold the magnet securely in place. The magnet acts as added weight to keep the LED upright when thrown.

Magnet attached to bottom

Figure 4. Affix the magnet to the bottom of the throwie.

Step 5: Enclose in Duct Tape

The final step is to enclose the whole throwie in duct tape to protect it and block the bright LED light from shining out the sides.

Wrap strips of duct tape around the throwie, covering all sides. Leave the top open so the light can shine out.

At this point your battery powered LED throwie is complete!

Completed LED throwie

Figure 5. The finished throwie enclosed in duct tape with the LED light shining out the top.

Using Your Throwie

To use your throwie, simply turn it on by taking off the tape tab insulating the battery. Then toss the throwie at any metallic surface and watch it magnetically stick! The LED will slowly drain the battery, giving you hours of temporary light.

Try tossing throwies in groups to create fun displays on buildings, metal walls, or other surfaces. Just be sure to retrieve them later and dispose of the batteries properly.


Building your own battery-powered LED throwie is an easy, fun project you can tackle in under an hour for less than $5. With just an LED, coin cell battery, magnet, and some simple taping, you can create a throwable light to stick anywhere.

Try making a few throwies in different colors and dazzle your friends with your creation! Just be responsible and don't leave them up permanently or improperly dispose of the batteries.

I hope you enjoyed learning how to make your own LED throwie on the cheap. Let me know if you have any other questions!