Instructables
Most sports-fans are familiar with the extremely loud air-horns powered by a can of compressed air.

This Instructable tells you how to make your own air-horn from common house-hold scraps.

With a little practice, each air-horn takes under five minutes to make, so an evening's work can produce enough air-horns for even the largest family to enjoy around the Christmas table, or to dole out as party-favours so that the dear little ones can take some of the party fun home to the parents who didn't help arrange the party... ;-)
 
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Step 1: Equipment and Materials

A sharp knife or scissors with a pointed blade.

A 35mm film cannister or similar plastic pot.

A balloon.

A straw.

(You'll probably have to buy the balloons and straws, but you can scrounge film cannisters from your local photo-developing store. I get 20 or 30 a time from our local "Boots".)

Step 2: Drilling.

The air-horn needs two holes, one for air to enter, one for it to leave. The exit hole, in the centre of the cannister's base, is most critical, since it needs to form an air-tight fit around the straw.

If you pause and check the fit every few turns, you should reach a point where the straw can be pushed snugly in without being crushed or distorted.

Drill a second hole in the side of the cannister, roughly the size of the hole in the base. Scrape the edges smooth, as this is where your mouth will be going.

Step 3: The Diaphragm.

Air-horns have a vibrating diaphragm to generate the sound. In this version, the diaphragm is a balloon.

Take an ordinary toy balloon and look at it. You should see that it has a crease around it. Since the diaphragm works best when it is flat, cut the balloon in half along the crease.

Step 4: Optional step - a big hole in the lid.

The air-horn works perfectly with a whole lid, but you may find it easier to adjust your first air-horn if you can see the diaphragm.

To this end, cut a big hole in the middle of the lid.

That's it. End of step.

Step 5: Assembly.

Lay the balloon over the top of the cannister and put the lid on so that it is pulled fairly tight. If you have a hole in the lid, you will be able to check that the balloon is smooth and tight.

Slide your straw into the bottom of the cannister until it presses against the diaphragm. Again, if you have a hole in the lid, you will be able to see where the end of the straw ends up.

That's it. The air-horn is made.

Go on, try it. Pucker up to the hole in the side and give it a blow.

Step 6: It Doesn't Work?

If you're lucky, the horn will sound first time. Well done.

If all you get is a feeble hiss, keep blowing and gently nudge the straw harder against the balloon by tapping against the end of the straw.

On the other hand, if you just get silence and bulging cheeks you need to pull the straw out very slightly.

Step 7: Hacking the Make.

I know you. If you're reading this, you probably won't stick to the basic instructions. You're probably already wondering if that plastic pot you keep your nails in would do the job, and you're fairly sure you've got an old rubber glove somewhere...

Yes, they probably will work. Film cannisters and balloons were just the easiest materials I had to hand, but I've also made one with a plastic snack pot and using the palm of a disposable rubber glove for the diaphragm.

Could you make one from a bucket? A dustbin?

What about the air supply? Blow too hard, for too long, you'll start seeing stars and have to have a nice sit down.

I made a basic model with a small inlet-hole, so it was a snug fit for the needle adaptor of a bicycle pump. That worked, honking nicely for every push of the pump. A larger stirrup-style pump I borrowed had a small air-reservoir, and with practice that gave a steady drone.

Tuning? What about tuning?

I haven't looked into this properly yet, but the note seems to be linked to the length of the tube you use, the tube's diameter and the tightness of the diaphragm.

Can you make it play a proper note? Could you make it tuneable?

Go on, enjoy yourself and don't annoy the neighbours too much ...
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Dumchicken3 years ago
this is kipkays air horn!
Kiteman (author)  Dumchicken3 years ago
No, this is my air-horn.

I avoid Kipkay's projects, as I prefer to read original work.

i'm saying that this is exsaklee (sorry for bad spelling)like his
Kiteman (author)  Dumchicken3 years ago
Check the dates.

I published this two years before Kipkay posted "his" horn.

Who do you think copied who?
yapoyo Kiteman2 years ago
He could have thought of the idea before you, but he made the video after this instruct able was posted.
Kiteman (author)  yapoyo2 years ago
Possible, but not likely, especially given the more-than-superficial similarity to the appearance.
he made the vid before this then he posted it after yours
Kiteman (author)  Dumchicken3 years ago
You reckon? Have you asked him?

Kipkay is known for lifting other folks' projects without giving credit.
Did you know, that this kind of instrument is a "Membranophone"?
Kiteman (author)  Dream Dragon3 years ago
I do now - thank you!
There have been "traditional" instruments that used "natural membranes" but latex based membranes like yours are fairly common on "DIY" bagpipes, they are less tempramental than reeds.
how would one compare the volume of this device?
Kiteman (author)  guitarwizard944 years ago
Use a decibel meter.

You can buy them, or you can even buy an app now!
Well other than having to spend money, like compared to something else in the home.
Kiteman (author)  guitarwizard944 years ago
Oh, sorry, I get you now.

Made well, they're loud enough to make people flinch and jump.  Think close to a referee's whistle.
Thank you very much! I was planning on using them at a hockey game in a week and wanted to know if they would be worthy enough! Great instructable!
Speedmite4 years ago
Just wondering, is tighter o looser better?

Also, I was quite annoying to my family hehehe....

I found that it is more effective on my make, to blow thru it backwards, having the straw as the outlet. Then it is also easier to tune, and hold the same note better. I used a long medicine bottle.
Kiteman (author)  Speedmite4 years ago
My best answer is it depends.

Changing the tightness changes the note and the volume, but too tight, and no air can get through, too loose and there is nothing stopping the air, and it just hisses.


Ok, I should have it good. I was just wondering If I should pursue tweaking, or leave it alone.
So the straw is vibrating to make the actual noise?
Kiteman (author)  bassclarinet234 years ago
No, the balloon vibrates as it rapidly lifts off the straw and drops back again.
Okay, cool. Nice instructable.
Kiteman (author)  bassclarinet234 years ago
Thanks!
minerug5 years ago
Great almost-instant project! Someone should feel sorry for my parents
Kiteman (author)  minerug5 years ago
Have you made them?
minerug Kiteman5 years ago
Yes, very pleased with the results
hobo joe5 years ago
thers lots of instructables on this stuff but got to say urs is the EZ est to understand.
I second that
Kiteman (author)  minerug5 years ago
Thank you.
Kiteman (author)  hobo joe5 years ago
Thanks, you're welcome.
Haha! :D
CameronSS7 years ago
hmmm...weather balloon, 55 gallon drum and air compressor...
How about weather balloon, air tank, air compressor, 2" pvc, 55 gallon drum, and a heavy duty drill. THAT might just work.
A) Don't know if that would even work and b) an air compressor wouldn't cut it if it did. Air compressors provide pressure, you need volume and only a little pressure. Maybe if you connected several (proper, electric ones with a tank) air compressors to one tank, or linked their tanks, that might work. One thing to be sure of: Even a weather balloon won't survive that much vibrating for long. It will get shredded before long. Try it anyway. With earmuffs.
Kiteman (author)  BlueFusion7 years ago
Air pressure is volume, but reduced (ie a large volume of air compressed into a smaller one). If a bike-pump can do it, a compressor certainly can. My only concern with CameroSS' idea is whether the ballon skin would be lastic enough.

But

That wasn't CameronSS' point. What he was doing was called "humour by exaguration".
I do know that; however it's not so crazy that someone might not try it. However, my point still stands. Try inflating an air mattress with a car compressor. It is designed to provide pressure, with low volume per stroke. You couldn't maintain a bouncy castle with a compressor. They use an air pump designed to give huge volume at only about 15 psi. An air compressor would not be able to deliver the volume per stroke to make the balloon vibrate.
Kiteman (author)  BlueFusion7 years ago
I think the only way to sort this is if somebody actually makes a 55-gallon air-horn and connects it to a compressor.

Now, I don't have a 55-gallon drum, so maybe ...

;-)
I aint gonna. I have a life. Anyway, what makes you think a bike pump could do it anyway? You need a constant pressure constant flow high volume air source, such as a bouncy castle compressor, actually a fan not a cylinder / piston thing. Not trying to argue, just debating it scientifically.
Kiteman (author)  BlueFusion7 years ago
I know a bike pump can do it because I tried it. Have you read step 7? Thus, since a manual pump can power a small horn, is it not reasonable to assume that a larger, more powerful pump can drive a larger horn?
A bike pump, or one with a small air tank, can power this. A bike pump works because it has a very large stroke. A car compressor would give an interrupted buzz and would not work with one much bigger than this, because the volume of the cylinder is only around 3 mL. There is only an air output around 40% of the time because the other 60% it spends pulling air back in and turning around between the two cycles. A compressor with a tank would work with something like this, but would need to have a reasonable sized cylinder to pump something like a 55 gallon drum. It would probably work BUT remember that you have to have reasonalbe volume per stroke. If the tank was charged initially, and maintained with a small cylinder, it would work for a bit then start to slow down because the pump couldn't keep up with the amount of air lost through the output. Remember, for something thet big you would need, like a 1" pipe. Maths tells us that every 5 inches of 1" pipe has a volume of around 12 cubic inches. You can assume that a larger diaphragm wil vibrate further, allowing more air through on each vibration. This is why you need a high volume low pressure supply. A car compressor not connected to anything will provide no pressure, and only little volume. Giving it something to squeeze the air into will let it create pressure. An air horn not only has an inlet, but an outlet too. Again, this is why you need volume.
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