LED Sims Plumbob (Remix)

After hearing the idea of being a Sim for a costume party, I decided to take it to the next level and make a costume for PAX (gaming convention). I found this Instructable by mrsayao and it was my main guide through the process. After the build, I realized that I took many of the original ideas and integrated my own, so this is probably more of a remix of the original guide I followed, but with his permission I'm posting my updated version.

The estimated cost will vary for you should you attempt the same build, depending on if you already have any of the materials along with other factors. But this is a fairly simple and very noticeable costume that pretty much anyone any gaming fan will recognize (even if it's only "Sim" and not specifically "plumbob.")

For this build, you will need the following materials:

• (4) 1W Green LEDs with appropriate heatsinks
• "Buckpuck" - along with the appropriate resistor
• Acrylic Sheet (18"x24" should be more than enough)
• Light diffuser
• Either a wooden dowel or clear acrylic rod (I used the latter) about 3 feet long
• Small length of pipe (about 2 feet) that your dowel/rod will fit into
• Some kind of harnessing method - I used a "running vest" but more on that later
• Power supply (depending on preference, either two 9v batteries or a portable cell phone charger) - more on this later as well
• Wire
• Solder
• Silicone in a caulking gun for easy application
• Hot glue
• Thermal paste
• 2.1mm power connectors, one male and one female
• (Optional) Green translucent paint

You will also need the following tools:

• A way to cut the acrylic. I used a Dremel but you can also use a standard "scoring" tool.
• Soldering iron
• Wire stripper

The plumbob exterior was made with pieces cut from a standard acrylic sheet. I drew out the design on the acrylic's protective film beforehand. I cut 12 tall triangles and one hexagon for the midsection. I did not remove the acrylic's film until it was time to assemble the pieces, but that was because I used the Dremel tool. If you use a scoring tool, separating the scored acrylic pieces will be more difficult until you remove that film.

I used a Dremel tool because I got a new one and was itching to use it.

For my plumbob, the hexagon measured 3.75" on all 6 sides. The 12 triangles measured 3.75" on the bottom and 7" on each side.

Once you have the 12 triangles, take off the film if you haven't done so already, and choose 6 pieces to assemble the top half. Take 2, line them up at opposing sides of the hexagon, and lean them in until they meet in the center. Put a small dab of hot glue at the top to keep them together. Take another piece and line it up at any available side and lean it inward, it should reach the center where the other two are. If it does, then take your glue gun and apply a strip of glue along the connecting edge (just not to the hexagon). Repeat this process with the other three pieces. Once the glue dries, you have your top half, and this sucker is pretty sturdy with all 6 pieces.

Before you assemble the bottom half, take the pipe and put it in the center of the top half. Measure the length of pipe to get from as far to the top as the pipe will go to the bottom, should be about 6 inches or so. Cut your pipe to that length and put the rest to the side for the harness. Find the center of your hexagon piece and if you haven't already, remove the film on one of the sides. Glue your pipe to the center of the hexagon.

Lay the other hexagon side face down, and start with two pieces of the remaining triangle pieces and place them at opposing ends like you did before. They will still meet in the center, but will also rest on the pipe. Cut the tip off each of the triangles at the part where it meets the pipe, roughly one inch. Once you've done that, assemble the bottom half in a similar fashion as you did the top half, just don't glue to the pipe or the hexagon. Once you're done, you have both your top and bottom halves completed.

This is where I mostly followed the original Instructable. You're basically going to connect four LEDs in series, and connect it to the Buckpuck. You will also need to connect a 1w resistor to the Buckpuck to limit the amperage going to the LEDs. These LEDs are rated at only about 350mA, so we need the resistor to set that for us.

The Buckpuck I used was a 1000 mA model, and I think that's the most common one (at least, it was when I looked on eBay...) If you're also using this one, you need a 1750 ohm resistor. If you are NOT using the 1000 mA model, then you need to calculate the value of the resistor.

A small piece of PCB may be helpful here to make the connections. I just cut one from a larger "scrap" piece I had. There are six connections to be made on the buckpuck. The input power, the control pins, and the output power. Connect the resistor between the two control pins. To connect the four LEDs in series, connect the negative end of one LED to the positive end of the other. Once you have that series made, connect the positive end of the output of the Buckpuck to the positive end of the first LED in the series. Then connect the negative end of the last LED to the negative end of the buckpuck.

Test the connection. You can either use a couple 9Vs in series or a 12v power adaptor of any kind. If all the LEDs come on, you're in business.

Attach a heatsink to the LEDs with thermal paste. I used some which are used for voltage regulators because they ended up being the perfect size. Remove the protective film from the other side of the hexagon so that the LEDs will shine through the crystal clear midsection and therefore, the entire plumbob.

The first three LEDs will be arranged at 120 degree angles. Glue the bottoms of the heatsink/LED assemblies each facing a different "section". This will provide nice coverage for a full 360 degree area. The remaining LED will be placed facing upward. and will cover the top. Glue that to the top of the frame of the other three LEDs. It's not necessary, but I did it because the top of the plumbob should not be dimmer than the rest!

At the original author's suggestion, I secured it using silicone as he suspected that just hot glue here would melt due to the LEDs. I'm not too sure about that, but I never tried it either. I used hot glue to secure the heatsinked LEDs to the hexagon and each other in few points, but then covered the whole thing except the tips of the LEDs with silicone. It wasn't pretty, but it got the job done.

Connect your power source to the buckpuck again. If the LEDs come on, you're still good. Connect the female 2.1mm power adaptor to the input of the Buckpuck. You'll need to allow enough wire between the adaptor, the Buckpuck, and the LEDs to reach from the bottom end of the plumbob to the midsection. This is so you can easily attach and swap out your power source. I also hot-glued the buckpuck to the pipe in the lower half.

I used green translucent spray paint (and a thin layer of clear "Flex Seal" as I thought the Flex Seal would diffuse the light enough but then I took a different direction. I don't think it's actually needed.) to cover the exterior. Before long, the green was the desired darkness. Once it dries, just bring the pieces together with your hands and realize this is really happening.

Get some diffuser material. I had some from a friend's leftover project, but it's pretty easy to find. Basically this is to spread the light out. Make 12 triangles about the size of the pieces you were using. Glue them to the interior sides of the plumbob (one small dab at each corner of the triangle should do the trick). Test by resting each half on the top of the light assembly one at a time. If you do it right, the light inside should spread uniformly throughout the entire plumbob.

While you're here, put a small line of silicone at each of the joining vertices in the interior. This will help secure the diffuser material further AND help waterproof the interior.

You now have two halves of the plumbob exterior, painted and diffused, along with the interior with the pipe and LED assembly. You're ready to assemble the plumbob pieces. Balance the bottom half of the plumbob (the part with the hole) on something like a roll of duct tape. Now lower the midsection, pipe down, into the bottom half. The pipe should just about reach the hole of the bottom half, and more importantly, the female power adaptor should protrude through the hole. This is so you can plug it in to your power source later.

Hot glue the edges of the midsection to the edges of the plumbob. Now take the top half and place it over the midsection, and glue that into place. Plug it into a power source and congratulations, the main plumbob assembly is now complete!

Depending on your materials and expertise, you have a couple options on how to power your plumbob out in the wild. I actually prepared two so I had a backup plan. (After all, I was attending a 3-day convention!)

Option 1: Two 9v batteries, and something the size of an Altoids tin (just make sure you line the interior to ensure no metal contacts cause a short). Advantage: All you need are two 9v battery clips, probably less expensive. Disadvantage: depending on the length of the event, you may go through a lot of batteries. Two of them last about 6 hours before they get too dim to notice in brighter conditions, but that can be stretched in darker conditions.

Option 2: A portable cell phone charger (one of the bigger ones that can charge your phone fully multiple times, not one of those dinky "emergency" ones).and a 5v to 12v "step up" converter. The battery packs are more expensive but you can recharge multiple times over. Also, if you shop around on one of those "deal a day" sites you can pick up the battery charger for fairly cheap. Most of them output at 5v, and that's where the step-up converter comes in (you can find that for less than $5 on eBay, shipping included). It clocks the 5v voltage up to 12v, but the mA will be reduced. But this only requires 350 mA so that shouldn't be an issue.

Whichever option you choose, connect the leads to a long wire (from about a foot above your head to your pocket where you'll hold the power source. The other end of the wire will connect to the male power plug. If you need help connecting the wires, look up "splicing wire to NASA specifications" and you'll find a good technique.

Test the connection and plug your wire into the bottom of the plumbob. It should light up, and you're almost there.

Get that other part of the pipe you reserved from earlier, and find yourself you can use as a harness. I got a running vest meant to increase visibility, but I got it because it has straps that go around the chest. Duct tape the pipe to the back of the harness, and the bottom of the pipe to ensure the rod attached to the plumbob doesn't fall through.

When it's game time, strap on the vest with the pipe in the back and put a shirt over it. The top of the pipe should be near your neck so it should make it easy for you to take on and off (like if you're getting into/out of a car). It takes a few tries to do by yourself, and there's no shame in having a friend help you out either.

Wear the harness, plug the rod into the plumbob and then the harness, and then plug in your desired power source. You have completed the plumbob!

Depending on if I have the time, I may try to improve on this project. Ideas include:

• Color changing ability. Obviously you wouldn't paint the exterior green in this case.
• Aspect ratio. The final product was a litte "fatter" then the plumbob in the games (though everyone still knows what it is). I would either shrink the midsection or make the triangles even taller.
• Construction changes. While it was pretty sturdy with the Dremel-cut and hot-glued acrylic, I think I might want to employ either a laser cutter for the acrylic or 3D-print a "translucent" colored material to get more exact construction. (3D-printing a translucent material would likely reduce the need for a separate diffuser)