How to blow an Aztec Death Whistle

[bradleyheathhays]

 I'm trying to set up a deterrent system and after a lot of thought I think I've figured out how to do this. This situation is fairly unique so I'm afraid suggestions other than the path I'm pursuing probably wouldn't apply. So I'd like to keep the discussion on the right path if at all possible. My goal is to create a continuous stream of air that would blow into an Aztec Death Whistle. Youtube it if you haven't heard one. The audio doesn't nearly do it justice. The 'whistle' takes a good amount of breath to get going. A full set of lungs only gets about 3-4 seconds out of the thing. What I've found to be a good source of air for the whistle is my 18v battery powered Ridgid small shop blower, using the smallest 2Ah battery. It's a small blower about 18" long. The whistle's full volume may be reached using somewhat less air than this blower on full, but that's generally the volume of air I'm talking about. This blower isn't designed to run continuously so another style of air mover would have to be used for the final model.

The requirements are that the system needs to be able to run on both house electric or battery power. Normally it should run on house power, but if the electric gets shut off it will switch to battery. I'm hoping to get some kind of battery setup that'll keep it running for about 2 hours before it runs out. The last requirement is that the whistle should not be heard to vary in tone at all if the house elec is shut off and the device has to switch to battery.

Sounds devious huh?

Any thoughts?

[amyk]

I know this is an electronics forum, but I think a large bottle of compressed air may be more suitable to your application. Use a solenoid valve to actuate it, like an air horn, and refill it from a compressor.

[NiHaoMike]

Just replicate the sound with a speaker array?

[themadhippy]

maybe take look at how pipe organs work,blower feeds a reservoir that feeds the pipes.The reservoir should also cover any power switch over.

[ajb]

There are lots of "air mover" options.  To narrow things down it would help if you quantified your requirements.  You already have two points of reference with the blower and the human lungs.  If you look up volumetric lung capacity for a typical human and divide by 3-4 seconds, that gives you an estimate for the volumetric flow required, but not the pressure required -- although it gives you a maximum based on what a human can typically exert.  The blower might give you a pressure spec, but even if it does it may be hard to translate a single value to whatever the 'somewhat less than full' value is where your whistle works.  The good news is, it's fairly simple to create a water column manometer that can read the differential pressure across the blower.  From there, you have at least a starting estimate of the actual specifications required, and can compare those to things like off-the-shelf brushless blowers.