Hey guys! I plan on flying a strip of LED's at a festival with

Hey guys!
I plan on flying a strip of LED’s at a festival with some balloons!

I was hoping you guys might have some arduino code examples of some cool effects for a single long strip going straight into the air?

Look at Fire2012 in the FastLED 2.1 branch Examples directory.

And of course there’s fill_rainbow.

How many pixels long will this string be do you think?

300-600 pixels.
Depending on how much lift i can get with the helium balloons.

Led strip or wire with pixel nodes?
Strip is lighter per led, but shorter…

LED Strip.
I think with about 6-10 36" balloons, i should be able to fly 5m of Strip.
Im going to try for 10m of strip, but i doubt i will have the lift.
My strip is 2812B 60LED/m

Sounds cool!
I suspect lifting the power supply will be more of a challenge than lifting an Arduino and some LEDs.
Also, since the strips are very directional with their light, you might want to consider a diffuser of some sort. I like white or translucent “split loom ducting” aka cable organizer tubes. Also, white silk makes a great diffuser and is super lightweight.
I’ll see if I can offer a good link to a fun sky animation a little later in the day.

The batteries and the teensy will be at the bottom, the end, on the ground, and inside my book bag.

Ahhh! Then I bet you can lift more than you think!
Google around for the number of grams that that sort of balloon can lift, and then look up the weight of the led strip… I suspect you can lift a lot, especially if it doesn’t have the silicone sheath.

I do have the sheath, but I was thinking about removing it

Just worried about the rain setting in. I could always keep a waterproof bag in my bag in case rain sets in

Okay, I hate to be the downer here, but there’s a couple of problems with this. My “real” job is a balloon artist. I deal mostly with animal balloons, but I’ve worked with helium a fair bit.

There is a helium shortage. It’s a non-rewewable resource. This means two things - it’s going to be expensive as hell, and hard to get. A 36" balloon uses 113.1 cubic feet of helium. Expect to pay dearly to get it filled.

However, you should only need ONE balloon. The lifting capacity of a 36" balloon is approximately 7 pounds.
You can probably get away with a 16" balloon or two - they can lift about 280 grams each.

The other problem is that wind will screw it right up. It’s going to push those balloons all over the place, and unless you plan for it, it could wreak havoc with your wiring via twisting.

@Noel_Bundy : Thank you – this is awesome information. And talk about interesting “real jobs”!..

Also, try something like this, which is a nice effect (this is what’s running on the belt I put up a video of on the weekend):

uint8_t time;

void loop() {
for (int i = 0; i < NUM_LEDS; i++) {
leds[(i + time) % NUM_LEDS] = CHSV(
sin8((65535 / NUM_LEDS) * i) + time,
sin8((65535 / NUM_LEDS / 2) * i),
sin8((65535 / NUM_LEDS) * i * 3));

uint8_t sin8(uint16_t x) {
return (sin16(x) >> 8) + 128;

Thanks for the suggestions Noel!
I have previously flew “El wire” with balloons at festivals, and wanted to step it up a notch.

I’ve never ran into twisting being a problem with El Wire, but now that you brought it up, i can see how it can become a problem.
I dont plan on flying this in high winds or a storm or anything, so do you think that a simple fishing swivel would eliminate some of the twisting?

@Robert_Atkins , i saw your belt for the lady! Good work, and thank you!

It wouldn’t be a huge problem with a single balloon, but multiple ones will bounce and spin like there’s no tomorrow. I recommend using fishing line -> swivel -> fishing line to balloons.

Right on!
Noel, how do you do the math to know that a 36" balloon holds 113.1 cubic feet of helium?

Airgas said their $150 tank only holds 115ft^3, and he described this as a tank that takes 2 hands to pick up and can be put on my shoulder. 3ft tall and slimmer than a tank i would find at a florist/grocery store.

Is your math correct? AND,
That tank will only blow up ONE 36" balloon?

Well, volume of a sphere is V = (4/3)πr^3

which, when given 36" as the input, gives 195432 in^3 as the volume. Punch “195432 in^3 to ft^3” into google, it says 113.097 cubic feet.

On the other hand, a 16" sphere gives 17157.3 in^3, which is 9.93 ft^3.

And to calculate lift, a cubic foot of helium will lift 28.2 grams.

Admittedly, a balloon isn’t an ideal sphere, but it’s close enough for our purposes.

My math may be abit off, as i have not had a math class in quite a few years…
I think your math assumes im using a 72" balloon, as your using 32" as the radius.

Bear with me…

I have a 36" diameter balloon.
V = (4/3)πr^3
With a radius of 18", that would be V ≈ 17157.28 inches^3
Which would reduce down to V ≈ 14.1372 feet^3

So a 36" balloon would only hold 14 ft^3? Correct?

herp! Brainfart. You’re right! But hey, that’s why I posted the formulas.