Winter is coming! The days are getting shorter and the air is cooler which means you'll probably be wearing a jacket. Why not spice that jacket up and show off your skills with a LED zipper pull that looks like an arc reactor from Iron Man? In this instructable, I'll show you how to make just that. This LED zipper pull is extremely cheap and fun to make. In addition to looking awesome, it can also be used as a flashlight or a signal device for sending morse code. Using the arc reactor is easy. Simply press the core of the reactor to light the LED momentarily, or twist the core of the reactor to keep the LED lit. This reactor also uses a socket system that allows the wearer to wear the same core on multiple jackets without having to untie any knots. So without further ado, grab your tools and supplies and let's get making!

PS: don't forget to check out the video here

Parts and Supplies:

Thin sheet of cardboard with a glossy white coating (commonly found in electronics packaging)
12 ounce Gatorade bottle (other brands could be used but Gatorade bottles use very nice plastic)
average size LED in the color of your choice (I'm using blue because... Iron Man)
.89" Washer
1" Key Ring (medium size, needs to fit snugly in the mouth of the bottle)
Micro size momentary switch
Small 1.5-volt cell battery
Electrical tape
Black spray paint
Cord for tying the reactor to your zipper. (I use leather)
Thin copper wire (like what's used on microwave fan coils)
Paper
Small rubber earbud piece

Tools Needed:

Hot Glue Gun
Something to cut the bottle (this can be a hacksaw, a Dremel, or a reciprocating saw)
Utility blade
Pocket knife (as sharp as possible)
Drill
Sandpaper
Compass (unless you are really good at free-handing circles)
Scissors
Black Spray Paint

Step 1: Cutting the Bottle, Not As Easy As It Sounds

First, you'll need to remove the lid and retaining ring from the Gatorade bottle. Then you'll need to put the bottle in a vise and cut off the threaded portion of the bottle just past where the flange was that held the retaining ring in place (refer to photos). Gatorade bottles are made with very thick plastic so there is a good chance that the plastic will melt and make a mess if you are using a power tool so once you finish cutting you're going to need to take a utility blade and carefully shave off all of the melted plastic. Once the majority of the melted plastic has been shaved off, you'll want to switch over to a sharp pocket knife and carefully whittle away at the plastic so that it is as smooth and clear as possible. I would strongly advise that you clamp onto the piece with a pair of vise grips so that you can keep your fingers. To polish this piece up, place its face down on a clean piece of paper and slide it vigorously up and down. It is important that you use regular paper and not sandpaper because sandpaper will scuff the part and keep light from diffusing through. Please also note that throughout the rest of this instructable I will be referring to this piece as the "outer ring."

Step 2: Coils and Washers

Next, it's time to make the front face of the reactor core. First, you'll need to find a medium size key ring that fits inside the outer ring perfectly. Then you'll want to take you magnet or motor coil wire and cut 5 4" strips of it. To wrap the wires around the key ring, first, twist a small amount of the wire around the opening section of the key ring and then slide the wire around the key ring to the side opposite the opening and wrap the wire without overlapping until you run out of wire. Next, simply repeat the process five more times and make sure all of the coils are equally spaced and it's time to move on to the washer.

The washer you use will need to be smaller than the outside diameter of the key ring but just barely larger than the inside diameter so that it doesn't fall through. I recommend sanding and polishing both sides of the washer so that it A: will look pretty. And B: so that more light will bounce around on the inside of the core and find it's way into the outer ring.

Step 3: Preparing the Electronics

Now it's time to make the electronics pad. First, you'll need to use a compass to trace out a 1" circle on a piece of thin glossy cardboard and cut it out. Once the circle is cut out then take a small screwdriver or scribe and poke two holes side by and through the center of the cardboard for the LED's leads to go through. Push the led through the holes and hot glue it in place.

Next, it's time to add the switch and battery. First take and solder one of the leads from the momentary switch to the positive lead of the LED. Then bend the negative lead of the LED so that it is flush with the cardboard. It may take some wiggling but next you're going to bend the positive lead with the switch so that the bottom of the switch is touching the cardboard and the remaining lead on the switch is hovering over/near the negative lead from the LED. Once you've got that positioned, go ahead and hot glue the switch in place so that it won't move, and then position the battery so that it has a strong connection with the leads. Once you've pressed the button to verify that the circuit works, then carefully hot glue the battery in place. If your circuit isn't working then you need to get more pressure between the switch lead and the battery. Once the electronics pad is finished you're ready to assemble the reactor core!

Step 4: Assembling the Core

To assemble the core, you're first going to start by placing the key ring on a hard work surface and then pressing the outer ring over the top of it. This is the easiest way I have found to make sure the key ring is level. Next, you'll position the washer by centering the key ring and outer ring face down on top of it. Once you have the rings positioned, add a bead of hot glue all the way around the inside edge so keep everything in place.

Next, it's time to install the electronics pad. To do this first, do a test fit by carefully pressing the cardboard circle into the outer ring. If the cardboard has to warp to fit or the LED is not centered then take your scissors and trim the edges of the cardboard little by little until it slides into the ring neatly. Once you have the electronics positioned, carefully run a heavy bead of hot glue all the way around the inside edge of the electronics pad. Be extremely careful that while doing this you don't cause the cardboard to shift and give the hot glue plenty of time to dry. If the cardboard is shifted then the LED will be knocked off center. Once you've given the glue plenty of time to dry, (ten minutes should do) then try screwing the core into the bottle cap. If the light turns on then everything's good and you're finished with your core. If it doesn't, then the lead coming out of the switch probably isn't applying enough pressure to the battery. Before you begin working on the socket there is one final touch you can add. If you take a small, semi-transparent white earbud and press it into the core over the LED, it will act as a diffusion ring and disperse the LED's light more evenly throughout the core. it's completely optional but it does make a huge difference.

Step 5: Making the Socket

Now it's time to turn the cap from the Gatorade bottle into a socket for your reactor core to screw into. This is the piece that you can make multiples of so that you can have a socket on all of your stuff and always wear your arc reactor.

First off you'll want to take a knife and shave off all of the burrs that are left over on the inside edge of the lid from when the bottle was sealed shut. Next drill two 7/64" holes side by side through the edge of the cap just below where the threads end. After you've drilled the holes, give the cap a few coats of black spray paint to make it less conspicuous. Once the paint is finished drying then take and wrap a strip of electrical tape once around the outside edge of the cap. Then, carefully fold the tape into the cap and under the cap so that everything is nice and smooth. After you've folded the tape in, use you knife to cut out the tape where the holes go and then cut the tape on the inside of the cap so that it just barely covers the top edge of the first thread. The purpose of this tape is to keep the reactor core tight while it's in the socket so that it doesn't fall out or turn itself off. The final step in making the socket is to run some cord through the two holes and then tie the socket to the zipper of your favorite jacket. Once you've screwed in your core then you're finished!

So now you know how to make your very own mini arc reactor. I hope you enjoyed this project. Please let me know what you think of it in the comments. I'm always trying to make my Instructables better and I love feedback. Until next time thanks for reading and watching!