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Self-Flying Balloon Answered

I have an idea to make a bunch of smallish balloons that have a LED sinside and small circuits that would control small heating elements to randomly change the density of the air inside the balloons, making them rise or fall. Just as a fun art project, making a bunch of them and letting them into a room for a party or something.

A couple of issues I have: I'm having a hard time figuring out how to calculate the buoyancy, though that may have to come later once I decide on all the components.

I don't want to use any lighter-than-air materials like Helium, just regular air heated up. I've been trying to find some small ceramic heaters, but I haven't had much luck. Ideally, something like this seems like it would work perfectly, but I need to find some that I can buy in quantities less than 20,000: http://cdsk.manufacturer.globalsources.com/si/6008801115398/pdtl/Heating-element/1070197186/Surface-Heating-Elements.htm Whatever I choose would also need to heat up and cool down pretty quickly so the rising/falling would have a stronger effect. I might be asking too much here.

I'd need the whole circuit to be pretty small and lightweight. If I use an Arduino Uno, could I just transplant the ATmega328 into the balloon? If I used a small watch battery, would that even provide enough juice to operate an LED and a heating element? Anything bigger seems like it would be too heavy.

As for the casing, I plan on whipping something up in Blender and printing it out in lightweight plastic. It would have to hold the circuitry and be airtight to keep the balloon sealed.

Any thoughts or ideas would be greatly appreciated!


Problem your facing is overall weight. A typical party balloon doesn't hold enough air volume to lift much more than it's own weight with hot air alone. You'll burn up the balloon before you get a decent amount of hot air into it. A larger balloon wouldn't help much either. Not without it being filled with a lighter than air gas.

Now i've seen balloons that have small glow sticks in them and then filled with helium. I've even seen them with small LED flashers in them. Basically an RGB LED that has it's flasher circuit built into the LED then attached to a watch battery.

If you want them to rise and fall then hook up some motors to an Arduino and have strings going from the balloons to the motors.

I'd really want them to be independently flying objects without any tethering or external objects. Would it be possible to use helium, and still use a heating element to raise and lower it? I'm not much of a chemist.

Not a good idea. Helium is flammable. Besides heating a lighter than air gas is only going to make it expand and rise faster.

Here is another idea for you but will require some experimenting to get it all right. Attach a small PC fan or 2 that are controlled by a small micro controller to a large helium filled balloon. The trick is getting the weight just right so the balloon is neutrally buoyant so when the fins are engaged the balloon will rise and fall. This obviously requires some stuff attached to the outside of the balloon but it may be the best you can do.

Are you sure you're not thinking of Hydrogen? Hydrogen was what they used in the Hindenburg. Everywhere I've looked, I've found that Helium is an inert gas and is non-flammable.

If I did use Helium to make it float, I would assume that the weight of the equipment in the balloon would help keep it from floating too much, and if need be, I could add more weight to it. (It would be great to be able to include a larger battery or something like that)

And then, of course, use the heat to make it rise. The only question is, how much does the temperature affect the buoyancy of the Helium?