This is a walkthrough of what I did in an attempt to acquire a cool glowing sword (who doesn’t love a cool sword?). I had several problems that I will include ideas on how to mitigate or work around on a future attempt as well as what I actually did.

Materials:

• Hollow plastic sword
• Six red 3mm LEDs
• Two 3v coin cell batteries (and corresponding battery box)
• Three 100ohm resistors
• Conductive tape
• Stranded wire (multiple colors makes keeping track of parts crammed into a small space easier)
• Electrical tape

 

Tools:

• Alligator clips (testing purposes: please make sure circuit works at every stage)
• Soldering tools/supplies
• Some way of punching small holes in thick plastic (I had a dremel with various attachments)

 

Step 1

:

(Image is from a later step, but demonstrates the LED positions chosen and appropriate hole vs LED size)

Cut your primary access hole. Please think this through better than I did, I cut the handle entirely off from the hilt, and didn’t acquire an appropriate epoxy that would actually manage to reattach it with any sort of strength. Figure out which areas you can reach and where you want to put your LEDs, as well as how many, then  start punching holes for them. You want a hole just barely large enough for the LED so that it will pop through and stay somewhat well on its own. Test this with some LEDs right now, and make sure the hole is the right size while the LED is not yet attached to anything. You will also need 2 small holes for a wire to poke through from inside near where the blade and hilt meet, on opposite corners (see image below).

(The other hole is then in the same position if you simply flip the other side of the hilt to face up)

 

Step 2:

This is the eventual circuit diagram for my sword (I think I got everything aligned correctly). If you choose a different number/color of LEDs, your requirements will vary.

This step consists of making the three LED/resistor wires that will need to be placed in parallel later. Set your battery pack up with the alligator clips now, and test each wire as you go to make sure everything is connected properly and none of the LEDs have pre-existing issues (or got wrecked while you were testing the holes they will use later). There does need to be a length of wire in between the two LEDs, as the flexibility of not being connected directly to each other makes them easier to squeeze into place later. Not pictured above, the other end of the LED without a resistor on it on each piece should then be soldered to another piece of wire to make sure each LED has the necessary flexibility to be placed a (comparatively) large distance apart. Solder each connection, and then cover all exposed wires (that don’t have remaining connections to be made) with heat shrink and/or electrical tape. Things will get very cramped inside, and avoiding short-circuiting anything is tricky.

Step 3:

Test all of those wires in parallel via your alligator clip setup before moving on. My strings are coded such that the end of these pieces that, at this stage, ends at the resistors is the end that needs to connect to the switch on the blade, through which it will connect to the positive terminal of the battery pack. The other end has been done up in yellow wires. Your next job is to twist these around another wire (coded black here) leading to the negative terminal of the battery back, and get that soldered as well as you can. This was the hardest solder I did, due to how thick this entire bundle of wires is. I eventually found that starting at the thinnest part, where the single wire goes out, got it started enough to get solder going everywhere else. Test the connection again, then insulate. (I did not, but the resistor ends of the parallel wires should probably also be soldered to a single wire leading out here, I was encouraged to just electrical tape them to each other and the wire leading out when I got to that point, which I suspect was one of the causes of my eventual electrical issues)

*note: I did most of my insulation as I went, which may or may not be very good practice as you’re still heating various parts of attached wires with ongoing soldering. I am a novice. If my suspicion that this is not a great idea is correct, all of the insulation can wait until just before you start sticking this entire mess into the sword.

 

Step 4:

Now we need to get everything connected to the battery pack a little more permanently. Remove the alligator clips and get ready to start connecting things properly. I managed to make a wire nut work for one of them, but the other just refused to connect (possibly due to the disparity between the thickness of the two wires?), and I was able to improvise by twisting them together as tightly as possible and covering it tightly in electrical tape.

The red connection is the positive terminal of the battery pack and a new piece of red wire. The black one is the black wire from your parallel joining earlier to the negative terminal of the battery pack. (Workaround for uncooperative wire nut demonstrated with the black wires).

 

Step 5:

Time to get the creative switch part of this project moving! Starting from just above the two holes you made for the wires earlier, run conductive tape up the blade in a loose “double helix” style pattern. Try to keep the two stripes near (but NOT TOUCHING!) each other up the whole length.

(Remember these holes?)

This is the stage at which I finally joined the resistor ends of my parallel wires together with electrical tape (please don’t, properly solder them back in one of the appropriate soldering stages) to a yellow wire (yellow being my code for “intermediate wire, somewhere in-between components, in-between rather than on the positive or negative end of the confusing bits”) . Test at this stage by touching the new wire I’ve coded yellow (the one on the resistor end of the parallel wires) to one of the pieces of conductive tape and the red wire coming out of the battery pack to the other, and then touch some metallic object between the two strands of conductive tape. At this point, it was suggested later that I did too much touching the conductive tape with my bare hand while I was testing, which may have caused some of the issues. Don’t do it while the battery pack is on, just to reduce the likelihood of said issues. If everything is lighting up, you’re ready to start moving parts inside your sword. If not, make sure you’re not causing accidental shorts, the battery pack is on, and your connection between the tape strands is good. Clipping wires to tape might make this a bit easier.

 

Step 6:

If you haven’t done so already, now is the time to double-check everything is securely connected where it should be, and all bare wires are insulated (aside from the two leads, the red from the battery pack and the yellow from the LED conglomeration). The two spare ends (red from battery, yellow from LEDs) I decided to do just a tiny bit of solder on to smooth them down into a single contact point for later.

What I did: Carefully, but firmly, press each LED into their designated holes. Secure with electrical tape behind them. Tuck excess wire between components somewhere inside and off to the side, except for the bit leading to the battery. The cords still outside should be:

• The two leads (red wire from battery and yellow coming out of LEDs)
• Battery pack and remaining wire leading to it

Everything else needs to get tucked up inside of the sword, ideally out of the way of the two holes leading to the blade, which you will need access to in a minute.

What you may want to consider: Glue around their edges a bit before pushing LEDs into holes to make sure they stay there. I had a few issues with LEDs popping back out before adding the tape, which still feels a bit loose to me.

 

Step 7:

Now, one of the two leads (red, yellow) needs to poke out of each hole near the blade to touch the tape. Secure the exposed wire to the tape via whatever method looks the most visually appealing to you (I used more conductive tape and was very careful about where I put it).

  

Once both are connected, turn the battery pack back on and run one more test by using some metallic object to connect the tape lines. If it’s not working at one spot, try another. Your creative switch (and the circuit in general) are now in their final form.

 

Step 8:

Last step: close everything back up. This is the stage that gave me the most trouble, as various electrical issues were plaguing me by the time I got here and every time I got it in a position to try a new method of re-adhering everything and sealing it back up… last minute tests wouldn’t work.

Make sure the battery pack is ON before sealing, or it definitely won’t work. My best advice for sealing it well would be to actually acquire some epoxy meant for plastic (I didn’t quite realize that none of the other adhesion methods I considered would work until it was too late to acquire any). Alternately, I considered that “sewing” it back together by making some tiny holes on the hilt and handle sides of the split and using wire to thread them together might work, but my LEDs are a bit close to the split for that to feel terribly safe.

If you’ve managed it: Good Job!

Mine is currently in  such a state that nothing is quite working probably due to a poor connection somewhere inside. I’ve also noticed some problems with keeping the connection through the tape.