This is my response to the challenge set by Jairus of all to build a PVC war horn. As is my way, I decided to build the smallest and most annoying air human powered air horn possible. Costing about £1.50 and built from plumbing parts, a balloon and a drinking straw, this mini air horn can kick out over 110dB so ear protection may be required at high volumes.
Miniature air horn build
The smallest equal tee I could find was the 8mm version, although they also do them in 10mm, 15mm and above, and they all work. A standard balloon works as a diaphragm, although any sort of thin latex or rubber from gloves should also work great. I used a 15mm or 1/2 inch rubber tap washer that just happened to have the correct size hole in it, but they are very easy to drill out if you dont have the same good fortune.
The tension of the balloon stretched over the end of the equal tee will alter the pitch and efficiency of your horn, as will the pressure of the straw as it makes contact. For initial testing set the straw to make contact with the centre of the balloon diaphragm very lightly. When blowing into the straw you can tune the air horn by altering the pressure, sliding the straw backwards and forwards slightly to do so. And thats it.
Very loud air horn
It should be obvious air horns are loud, this is no exception. I measured easily over 100 decibels with both an App and a decibel meter, so either blow gentley or wear ear protection, you only get one set of ears. If you liked this you may like the homemade bird whistle project.
The above project is aimed at adults for education and entertainment purposes only, not to replicate. Anyone doing so takes full responsibility for their own actions.