Ever wanted a geeky piece of jewelry for yourself or a loved one? In this instructable I will show you how to make a pair of led earrings! They even change color, which makes them perfect to wear at parties.

Let's begin!

Step 1: Parts List

The parts for this build are very cheap and easy to find, let's see what we need.

M10 bolt
4 button cell batteries (LR932 or similar)
2 Leds (with changing colors)
2 Led holders
2 Earring hooks
2 transparent Lego studs
Solid core wire of your choice
Super glue

You can get 8 of those button cell batteries out of the small 12V battery shown in the photo. Simply pry it open with a pair of pliers, and you will find 8 batteries inside.

The flashing is done by the leds themselves, they have a small IC inside that cycles through the colours.

Step 2: Make the Body

The body of the earring is simply made up of solid core wire, super glued together. It seems strange, but it makes for a functional design. The wire will connect the led to the negative side of the battery, thus completing the circuit; but this will become clear later on.

Start by placing the led in the led holder and wrap the wire tightly around it. Add some super glue and make sure the wire is nicely wound around the holder.

When you reach the end of the holder, curl the longest lead (positive side) of the led so that it acts like a spring. Bend the shortest lead (negative side) to the side, and solder it to the wire. Then trim of the short lead (keep the lead, we will need it later). Add some hot glue to the underside of the led, to prevent shorts.

For the remaining part of the body, take your M10 bolt and twist the wire around it. It is important to follow the threads of the bolt, as it needs to accept a screw later on. Twist the wire until it has a height of about 15 mm. Hold it together with super glue, like the previous part. Remove a small part of the insulation at both ends.

Now we need to connect these 2 pieces. Do this by soldering the new part to the other solder joint. Reinforce with some super glue, and the 2 parts should form a whole. The button cell batteries should fit perfectly inside.

Take 2 small transparent Lego blocks and grind away the edge. I also went over it with sandpaper for a frosted look. This will enhance the visibility of the leds. Glue these pieces over the led, and the body is done!

Step 3: Make the Hanger

The part that will connect the earring to your ears will also act as the switch of the earring.

Start by cutting a small piece of the M10 bolt, and drill a small hole in the center (2 mm). Make sure to grind away any sharp edges. Cut a slot in the top, so that it looks like a screw.

Take the earring hook and attach the lead from the led you clipped of earlier. Push it through the hole and make a bend.

Now solder the lead in place, and try to get the hole filled with solder. As it is quite a big piece of metal, give it enough time to heat up, and also to cool down afterwards!

Now we can screw the hanger into the main body. The threads should match the inside of the body, because we formed it with the bolt. When the hanger touches the batteries, it will also touch the small piece of the body we stripped earlier, thus completing the circuit and lighting the led!

To make screwing the hanger in easier, I made a small "key" out of a Meccano piece. It can easily be attached to a key-chain.

Step 4: Succes!

You now have a set of flashing led earrings, perfect for parties! I put them in an earring box, together with some spare batteries and the key. They're not difficult to make and are a nice gift, so why not try it yourself?

I hope you liked the project, have fun!

Feel free to check out my other instructables: https://www.instructables.com/member/ThomasVDD/