The Whirlwind - an IPhone Horn Speaker and Stand That Fits in You Wallet!

In a deep "fit for infomercial" voice...
He he, sorry I just couldn't help myself :D

Joke aside, sometimes I have found myself sharing a video with family and friends, and yes, sometimes the volume is just a bit low.
So, I started to think.
Could I come up with some kind of speaker that could fit in my pocket?
Better yet, in my wallet?

Well, it turned out that I could.

How does it work?
The idea is to redirect sound to you (the viewer) which helps with the volume, but the horn itself will increase the overall acoustic efficiency of the iPhone.
Remember, it's a passive component and does not amplify the sound from the driving element as such, but rather improves the coupling efficiency between the speaker and the air.
Horns used to be called "acoustic transformers" because they help match the impedance between the speaker diaphragm and the air. The result is greater acoustic output from the speaker.

And how does it sound?

Well, in "get you wife and kids to listen to it" tests, it makes the sound out of my iPhone seem twice as loud and deeper.

So, If you use it in a noisy place (like a restaurant) you will be able to hear you video, but without getting the next table to complain.

Now, I'm including the "bone white" version of the Whirlwind, so that you can make your own versions (a steampunk version would look wicked)

Note: It's trivial to modify the horn base to fit any cell, not just the iPhone.

What you need:

• The PDF.
• Paper.
• Thin Cardboard.
• Glue.

Before you begin, you have to make a decision. For the horn material, good old white printer paper is fine. But you can try out other materials such as Tyvek or wrapping paper that has some cool design, it's up to you.

As to the base and stand, I used a manila folder, which is just thick enough to give support but thin enough not to create a bulk in my wallet.

And last, the glue. Since you will glue the horn with it, you need a flexible adhesive. I used UHU but any non-brittle glue will work.

Now, to work.
Download the PDF and print it out and cut out the parts.

Look at the pictures for the stand and horn base cuts.

The horn.

When I was thinking of ways to make the horn, I remembered reading a few years ago about research from Japan in using origami techniques to find ways to fold satellite solar cells. The goal was to fold them in such a way that they would occupy the least volume, but be trivial to unfold.

I looked for and re-found the original paper by Taketoshi Nojima that I had read a while back.


I took the model of a conical shell, and modified it in sketchup to make it bigger and longer.

So, it's basically century old Japaneses origami used in aerospace, recycled into a credit card sized collapsible horn speaker :D

Take the printed horn and start to fold.
The folds that form the polygons (solid lines) you mountain fold and the diagonals (doted lines) you valley fold.

It's easy, just look at the pictures and comments to guide you.

I recommend that you start from the smallest polygons, it's easier to fold them first than at the end.

Note to origami beginners:
There are only two types of folds in the cone. The mountain fold (imagine looking at a mountain from the top) and the valley folds (the exact opposite as the mountain: a valley).

Take a piece of paper and fold it in half. If you look at it from the side, in one way it looks like the letter V. That's the Valley fold. Turn it around and it's the Mountain fold (an A without the cross section).

So the horn only has these two simple folds. On the perimeter of the polygon, its mountain fold (the crease toward you) and the diagonals are valleys (the crease away from you)

Once you finish folding, the horn will start to curl up just like in the pictures.
Glue up the tabs to the other side and close up the horn.
Start at the big side, and work you way to the base.

I used a toothpick to help me guide and glue the parts.

Once you finish, fold up the horn and make sure the glue holds up.

Note: you will notice that the horn spins while it fold, how cool is that?

Take the base, and glue the horn tabs to it.

That's it, you finished!!

To put it away place the speaker on top of the stand and use the rubber band to keep them together and protect the horn.

To use:

1. Remove the rubber band and separate the stand from the speaker
2. Assemble the stand
3. Assemble the speaker base
4. Use rubber band to hold tightly to iPhone (be careful no to push all the way in and this way obstructing the cone output)
5. Deploy speaker
6. Enjoy!