Battle Blimps are Bluetooth/RFDuino-controlled blimps designed for truly insane battling. We've developed them to be filled with hydrogen for explosive battles at Burning Man, but this design also works filled with helium for dueling indoors.

Read on for lots of detail on the current design, schematics, code, and notes on assembly. Please note, though, that this is a project still under active development. In the push to Burning Man 2015, we'll keep publishing updates with more detail as we improve the reliability of all the systems and in response to feedback here!

If you'd like to support us in this final development push, get access to blimp PCB boards, or see some of the awesome schwag we've designed, please check out our crowdfunding campaign on IndieGoGo.

Step 1: Things You'll Need

(As noted previously, all of this is still under active development!)

Battle Blimp Brains

Soldering station/reflow setup for surface-mounting components. There are tons of good instructables on this topic.
Lots of little electronic components. We have a preview bill of materials currently under development. After Burning Man 2015, it will be updated with our battle-tested (ha!) design.
Our Battle Blimp PCB. You can preorder this on our crowdfunding campaign, but once the designs are finalized this fall, we will also publish them here.

Remote Control Systems

Xbox controller
Computer with a bluetooth adapter, running VirtualBox

Lift Systems

Helium, plus a latex balloon (cheap, easy) or Mylar (slightly more expensive).
For hydrogen battles, you will need PLA/Corn plastic sheeting (e.g. a compost bag), nichrome wire, a voltage controller, and Kapton tape.
And of course, helium or hydrogen

Airframe and Propulsion

Lightweight spars (carbon fiber, balsa, or thin steel rod)
Motors, propellers
Wire and connectors
Fin material (paper or thin plastic film for Helium battles, or high-temperature Kapton film for Hydrogen battles)

Ignition Systems (for Hydrogen battles)

Nichrome wire
Snap-off blades
Safety gear!

Step 2: Blimp Brain

The brains of a Battle Blimp are a PCB with an RFDuino and many other components surface mounted on it.

An aside: Surface mounting is an awesome thing to know about. Learning to do it is like peering behind the curtain into the secret world of tiny manufactured goods that rule the world. It is amazing that you can actually just make this stuff. As noted before, there are tons of good instructables on how to learn to surface mount your components.

We'll provide more detailed instructions soon. Again, you can preview the bill of materials we currently have under development. You can also preorder the Battle Blimps PCBs on our crowdfunding campaign. Or, just check back here in the fall, when we will publish the designs for our production hardware.

All of the Battle Blimps source code is open source. Check out our Github repository, which includes some more-detailed instructions on setting up the hardware, installing the Arduino ans RFDuino libraries, and compiling the source to be loaded onto the Battle Blimp controller.

Step 3: Remote Control System

Our remote control system currently consists of a laptop running VirtualBox, routing an Xbox controller's signals over bluetooth to the Battle Blimps. For detailed instructions on this, visit the aforementioned Github repository and follow the remaining steps:

Install VirtualBox
Get Ubuntu Image
Set up Bluetooth Hardware
Set up Remote Control Software
Compile Pygame
Get the Xbox Control Working

Step 4: Lift Systems

A simple lift system for a Battle Blimp can be nothing more than a latex or mylar balloon filled with helium from your local party store. Fly your blimp around and try to ram your friends.

The next level of destructive fun is to mount needles on your blimps (wear eye protection!) and pop opposing blimps. These indoor blimp battles can be lots of fun!

However, we believe that true blimp battles involve sending your friends down in flames, and for that we've ended up creating our own hydrogen gas envelopes. There are a couple reasons we did this. First, most balloon material is toxic to burn, and we intend to hold several hundred blimp battles. Second, many balloons (e.g. latex) hold gas under too much pressure, and our early tests have shown that igniting these can be dangerously loud (and also shoot flame directly back at the attacking blimp, which is less fun).

The material we settled on is corn-derived PLA bioplastic, which burns cleaner and is fully biodegradable. The photos above show our process: Using nichrome wire (similar to what is in your toaster oven), we created curved patterns taped down to plywood with high-temperature Kapton tape. Compost bags (or other PLA film) is folded and laid on top, and then we run current through the wire to heat it up and create a seal along the seams.

The resulting balloons hold air quite well for balloons that only need to survive for about 15 minutes at a time. The life expectancy of a Battle Blimp will likely be much shorter than this :P

Step 5: Airframe and Propulsion

A Battle Blimp airframe has three main spars for rigidity, wrapping around the gas envelope or balloon. At the nose are small motors for pitch and yaw, and at the rear is a larger motor for thrust.

We 3D printed the connectors and motor mounts for our airframes (files coming soon!), but as you can see, the shape of the airframe is very simple. There are basically two 3"-4" tetrahedrons, one each at the nose and tail, with three spars connecting them and securing the balloon in the middle. So, you don't need 3D-printed connectors to build a blimp: Our initial prototypes were literally bits of carbon fiber rods taped together into the same structures you see above.

The tail fins help Battle Blimps fly more true. For our flammable balloons, we use Kapton film (the same high temperature film we use to tape down our nichrome wire for manufacturing gas envelopes), simply stretched and taped across a curved piece of carbon fiber or (very thin) steel.

Step 6: Ignition System

To set your foe's Battle Blimp ablaze, you need an ignition system. To build ours, we mounted small blades (tiny snap-off blade segments from standard hobby knives) in front of a coil of nichrome wire. When ramming another blimp, the blades create a small, v-shaped puncture in the gas envelope, shooting a column of hydrogen back over the ignitor.

You can guess what happens, then:

Catastrophe: The attacking blimp also dies!

The video attached to this step shows a series of test ignitions we've done, using different blade orientations and designs to maximize the ignition reliability when striking at different angles and also with different guard designs to avoid fouling of the ignitor coil when molten plastic starts flying around.

Step 7: Find (or Create!) a Place to Battle

For helium battles, any indoor space without wind will work. A building atrium or even a large living room work pretty well.

For hydrogen battling, though, we need to carefully separate the explosive Battle Blimps from the players and spectators. At Burning Man 2015, we'll be constructing a 3V geodesic dome to house these battles, with a screened cylinder within where the blimps will fly.

Step 8: Thanks! (And Bonus Video)

Want to see the blimps flying? More video and exciting info about our project? See the video we made, above, for our campaign at http://igg.me/at/battle-blimps. Also, visit us if you'd like to help us bring this project to completion and get some Battle Blimps PCBs!