Electro-Flare ...from X-COM: UFO Defense




Introduction: Electro-Flare ...from X-COM: UFO Defense

About: We build a lot of projects... Hopefully, we'll bring more to Instructables soon.

Before we start. An explanation of what this thing is, and why we built it, is in order.

It starts back in the early 90’s… 1993 to be exact. A video game was released called…

X-COM: Enemy Unknown.

In 1994 the game was released in the North America as X-COM: UFO Defense.

The by-line read "Extremely close encounters"

Troublemakers review:

It was roll playing game crossed with strategy that felt like non-stop action. It is, in fact, the best game ever made.

It’s a fun game.

You command a group of soldiers, scientists, machinists, in a desperate attempt to learn about your mysterious foe. Scientists research new equipment; machinists make it, and the soldiers try to use it to the best of their ability.


What made this game fun so immediately, to me anyway, was the suspense. My first mission was to investigate a UFO landing site… at night. SEE VIDEO above of Electro-Flare use in-game!

My soldiers couldn’t see very far. The game had a tool that can aid soldier in this situation… the Electro-Flare.

It is a throwable device that will illuminate large portions of the map where the Electro-Flare lands. First alien I saw was in some tall grass, but in the dark. Had a soldier throw an Electro-Flare near the alien… it was a “Sectoid.” The game called them that… but we all know them as the “Greys” or, you know… big head, big eyed aliens.


The Electro-Flare, I always thought, was a cool idea. An intense light that can be thrown into dark areas.

We always wanted to make one, and here is our attempt.


Step 1: Real-life X-COM: UFO Defense in Action!

A little demo of what we are creating...

Step 2: How We Went About Designing It.

Around the shop, we use these Sistema brand Klip-it containers to hold parts.

This xx oz. round container seemed like a similar shape and size to the original X-COM electroflare. See (picture of pixelated game icon and container). The in-game Electro-Flare looks puck shaped.

We knew we needed

- LEDs

- Batteries of some kind

- An on/off mechanism

- A container to build the project into


We really wanted to emulate the games effect of throwing light everywhere. We thought that using the smaller but more numerous 3watt LEDs instead of the much larger 10 watt LEDs would give us that effect.

To test this hypothesis without actually building a 10 watt electroflare we soldered 16 of the 3 watt LEDs to a pair of stripped 12 gauge wires and powered it with CR123a batteries. The test was blinding.

We didn't actually build a version of the flare with 10 watt LEDs but we are very satisfied with the 3 watt results.

Along the way we decided that we didn't want to drill or punch any holes in the container. The idea was to make a pass at keeping the whole assembly watertight.

How to turn this thing on if there aren't any holes for a switch? Reed switch. However the ampacity of the reed switch was far lower than the current demanded by our.

We slaved a small, usually board mounted relay to the reed switch.

I know, what is essentially a glorified flashlight is getting a bit rube-goldberg-ish.


We went with the lithium-polymer version of a CR123a battery, the 16340. We got a few of these from Amazon.

They are listed at 1200mAh but that seems pretty unlikely. They are probably more like 550mAh like most other 16340s. We wanted to be able to recharge the flare batteries rather than burn through alkaline batteries.

* High strength acrylic hot glue was used for much of the assembly.

* Thermally conductive epoxy fastened the LEDs to the aluminum tube. Thermal epoxy

* An internal structure to hold the LEDs and hopefully act as a heat sink was needed. We just happened to have a length of aluminum tube laying around that was perfect for this purpose.

During the build, it occurred to us that the heat build-up from the 22 little 3watt lights might start to make the environment inside food transport device/project box mighty toasty.

So, a 65C thermostat switch was wired in series with the LED array and epoxied to the inside of the aluminum tube. Now we had a safety mechanism to keep heat buildup from melting the shell and or auto-igniting the lithium batteries.

Before the complete assembly we were gonna use 4 batteries but there was room 5 so, why not, right? Also we wanted to add some lights to the cap to throw light “up” as well as just out to the side.

Materials Needed


Thermal epoxy

Normally closed temperature switch

Battery holders


3V SPDT Relay

Metal tube

3 watt LEDs

A big magnet (any strong magnet will do)

Cherry MP201802 normally closed magnetic switch

A sheet of thin plastic

Electrical tape

A piece of foam (any will do. You can cut to size)

Tools needed

Sand paper



Hobby knife

Hot glue gun

Electrical tape



Soldering iron & solder

Step 3: The Circuit

The black schematic is the main one to follow. See above.

You will notice the LEDs are not directly connected through the magnetic switch. The ampacity, the amount of current, the switch could pass was very low. Instead, we use the switch to activate a relay. The relay then passes the current to the LEDs.

We also included a thermal cutoff switch on that relay activation connection the magnetic switch is on. The purpose here is heat. With 22 3W LEDs on, the batteries heating up from use, we knew heat wold be an issue. And, during testing it was! After a few minutes of use, the switch would cut off the power.

NOTE: Installing some sort of active cooling inside the case would be a good idea for future builds. We would recommend a fan on the top, and holes cut on the sides. The metal ring is a good heatsink, but it needs more.

For the simulation below, using circuits.io, I made some changes.

1. Instead of the magnetic switch, I placed a single slider switch in the top left area.

2. Instead of 5 CR123a batteries, I placed a 9V as a placeholder.

3. Removed the thermal cutoff switch... can't simulate that here.

4. Used regular LEDs instead of the 3W options. The 3W ones do not need a resistor to prevent the element from burning out.

Despite the changes, the simulation works like the real device.

NOTE: The purple wire is the relay control line. That is what the switch is activating. Inside the relay block, you can see the switch moving when you activate the switch.

Step 4: Preparing the LED Mount Cylinder

Cut and shape the aluminum tube to a convenient length. It just has to fit in the container, the exact length is not important.

Step 5: Calculating Cord Length

Measure the outside diameter of the aluminum tube and calculate the chord length between LEDs using the the formula
(Diameter of tube x pi) / (number of LEDs) = chord length For our electroflare here, the tube has a diameter of 3.175 inches and we want to epoxy sixteen LEDs onto the tube. so (3.175 x 3.1415) / (16) = 0.623 inches between LEDs or about ⅝” Don't worry about getting this perfect. We just used a caliper because we have one.

Step 6: Make a LED Spacer Tool

Carefully cut a spacer that measures the length calculated in the formula. Use the spacer to evenly scribe vertical lines around the circumference of the aluminum tube.

Step 7: Laying Out the LEDs

Mix up a small batch of the Arctic Silver thermal epoxy and start pasting the LEDs onto the aluminum tube. Make sure that all the LED pins of the same polarity point in the same direction. (i.e. all negative pins point down and all positive point up)

Step 8: Wiring Up the LEDs

Solder 20 gauge wire to the LEDs as shown. Apply heat shrink tubing to all the solder junctions. It helps to pre-bend the negative wires as shown. Use the glue gun to stick the stray wires to the aluminum tube.

Notice the way the wires we started wrapping the wires at the top into a spiral pattern. It was a bit tedious, but with a bit of work, we got all the wires into the swirl pattern. The goal here is to solder all the positive leads together and all the negative leads together wherever we could while making the wires take up as little space as possible.

Step 9: Make LED Ring Base

Lay the body of the container onto the thin sheet of plastic and trace the outline of the container with a sharpie. Then cut the circle out of the plastic with the tin-snips. The circle is going to need some trimming because it needs to be able to drop down into the container itself.

Step 10: Soldering to the Relay

Solder some 22 gauge wire to the pins of the relay. Apply some heat shrink tubing to the solder junctions.

Always add heat-shrink tube.

The posts on relays like these are very small and thin. If you hold the soldering iron on the pins too long, they could melt, bend, break. So, make sure the iron is clean, and very fine. A needle like tip is the best option.

Step 11: Wiring Battery Holders

Solder 20 gauge wire to the battery holders. Do to each of the battery holders.

Step 12: Attach Battery Holders and LED Ring

Hot glue the the aluminum tube to the plastic disc and the battery holders into the inside the tube.We spaced the battery holders out fairly evenly so we didn't have all the mass on one side of the Electro-Flare.

Step 13: Place Metal Disc on the Lid

Use the tin snips to cut a disc out the of sheet metal. The exact size and shape isn't important as long as it fits under the container cap and leaves room for the lid LEDs. Glue the metal disc to the lid with either super glue or a thin layer of hot glue from your glue gun.

Step 14: Foam Spacers for LED Ring

Cut out some cubes of foam and hot glue them around the circumference of the aluminum tube. This will require a bit of trial and error to get right. It doesn't have to be even close to perfect though. We did this to keep the internal bits from jiggling around inside the container.

Step 15: Placing Magnetic Switch and Lid LEDs

Super glue or hot glue the magnetic switch to the metal disc glued into the container lid. Also glue any extra LEDs you want onto the lid. Sticking these LEDs to the lid is not done like the LEDs from the previous steps because in this step, the glue is applied to the light emitting side. We used big globs of clear silicone sealant for this. The silicon sealant not only holds the LEDs in place but acts as an insulator to the solder joints. Note how the wires were stripped here. We used a hobby knife to remove little sections of the insulation as needed from the 20 gauge wires going to the LEDs. Make sure you use “clear” silicon sealant in this step.

Step 16: Wire It All Up!

Wire everything up. Solder all electrical connections and apply heat shrink tube to these joints. If you want, the temperature sensitive switch can be fixed to the aluminum tube with some of the thermal epoxy.

Follow the schematic

Step 17: Support Those Batteries!

Take some of the foam and tape it into a roll. This is another anti-jiggle feature. This foam roll will be placed down the center of the tube to keep the batteries from bouncing out of their holders during and rough handling.

Step 18: Final - Place the Magent

Magnet we used is from an old harddrive.

Final assembly. Stick the magnet to the lid. Dont skip this step. Remember, the Electro-Flare is turned on when the magnet isn't stuck to the lid. Install the batteries along with the foam roll. Now, carefully tuck all those loose wires, the relay and the temperature switch into the container and snap the lid down.

Step 19: Real Electro-Flare Side-by-side With Its Counterpart

Here it is, in all its glory... the real-world Electro-Flare on the left. The one from the game, on the right.

(Future version needs an orange top!)

Step 20: Electro-Flare Epilogue

This whole project is an exercise in extreme cosplay. For X-COM... I'll cosplay.

The "Sectoids" are the character sprites I pulled from the game manually. I got to the point in the game where I can mind-control aliens, and I did so to some Sectoids. I just placed them in the orientation I wanted to see and edited them out in PS.

I sized them a little over 3 feet tall, which I figured they would be in real life.

As for me, I wanted to look like a rookie in the game. I found some work cover-alls that looked the part.

The Eletro-Flare was perfect. It turned pitch-black areas a lot less scary... It's a completely useful tool, not just for games.

Step 21: Teaching/Learning & Other Uses

We made this project as a way to teach a few concepts:

1. Wireless activation without a tactile swtich. Which we accomplished with a magnet and a reed switch.

2. Powering high-power LEDs through the use of a relay.

3. Adding in a safety measure in case of an over-heat situation. We accomplished this with an addition of a thermal cut off switch.

4. Showing use of thermal epoxy and high-power LEDs.

5. And promoting one of our favorite battery types, the CR123a.. a 3V battery is very useful.

Other uses outside X-COM cosplay.

The Electro-Flare is a non-chemical, non-burning type of light source. Throw-able and durable, here are a few alternative uses.

1. An emergency light source. In the event of a disaster, or some situation, having a hassle free intense light source is key. The Electro-Flare can illuminate a rather large area, turning pitch-black to clearly visible. I wrote about something similar on element14, though that one is not quite throw-able!

2. Special effects, for sure. When activating the light on camera, it looks like I am holding a rip in time-space. A portal to another dimension!

3. Monster and ghost repelling nightlight...Light so intense, those bad things in the dark stand no chance! See the picture above... that scary hallway was pitch-black, not a sliver of light. Of course, I thought there were creatures down that hallway. The Electro-Flare made it safe to travel in!

Step 22: More Pictures!

1 Person Made This Project!


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9 Discussions


3 years ago

One of my most favourite childhood games!! Great!!!


3 years ago

best game ever, indeed!


Reply 3 years ago

I tottaly agree with you!!


3 years ago

Really good gamer!!111


3 years ago

man, this is cool. But I really ould shat my pants if I saw that et on my backyard! ahahahaha

OSH Park
OSH Park

3 years ago

Well done!


3 years ago

I am a simple man.. I see X-com and I press favourite button.


3 years ago

Nice build,

if you added added a 3-5 sec delay it would be really fun in a midnight paintball game that way you could throw it without giving away your position, or you could add a tripwire