I'm hoping someone can recommend a part off the top of their head. My project needs to play an air horn sound effect (or as close to this as possible), the louder the better. Power limits are either 3v from a pair of AA alkaline batteries, or 9v from a 9v alkaline battery. My box is about 4x4x4 inches, so anything that operates in this power range will probably be physically small enough to fit. Can anyone think of an off-the-shelf part that might work?

The solution I have now is to store a PCM sound clip on a flash chip and play it through a speaker via a TFA9879 amplifier IC, but I'm hoping for a faster to implement and less expensive option.

 

I have used salvaged Air sirens from auto-wreckers, I assume these were theft protection, they are made by Alpine and they have a few models to choose from, the one I have is deafening.
Max.

 

Thanks for the suggestion. I'm should mention that we may be making a lot of these, so I need something readily available new and not much more than a few bucks each.

 

One selection of smaller ones.
https://www.google.com/search?q=ele...fgquzaAhVn0oMKHX1PCT0QsxgIKg&biw=1920&bih=961
Max.

 

You can certainly get piezo buzzers,etc... as shown in the links above.
I'm not sure I would ever classify them as "close to an air horn effect as possible" by any means though..

I'd start my search here though for sure..
http://www.mallory-sonalert.com/AVBySeries.aspx
They have audio clips on the site so you can "try before you buy"

 

Power limits are either 3v from a pair of AA alkaline batteries, or 9v from a 9v alkaline battery.

About the loudest (and least expensive) thing I am aware of would be the sounder in a smoke detector. There has to be a source to buy only the sounders and considering how inexpensive a simple smoke detector is I don't see the sounder elements costing much. Here are a few ideas.

Ron

 

Thanks all. We're using a piezo now, but looking to replace it with an actual air horn sound, or as close as we can get. I'm not expecting the same volume level obviously, but we want someone who is familiar with an air horn to recognize it as an air horn.

 

I believe that if an air horn sound is what you want then you will need to look into a custom speaker/audio file solution..

 

If you are looking for a relatively lower frequency horn sound than the small piezo type, it may require a larger diameter unit.
Max.

 

Thanks all. We're using a piezo now, but looking to replace it with an actual air horn sound, or as close as we can get. I'm not expecting the same volume level obviously, but we want someone who is familiar with an air horn to recognize it as an air horn.

I think the problem you will have is most people understand what an air horn sounds like, we have all heard air horns on trucks and trains as an example. The problem being an air horn on a truck does not have the same sound as an air horn on a train and neither sounds like the air horn on for example a tug boat. Would you like an air horn between 150 and maybe 400 Hz? Horns become a science all unto themselves, as can be seen in this brief white paper.

To me, a smoke detector sounds like an air horn, albeit a high pitched air horn but none the less an air horn. Likewise the fog horns used on ships have a much lower frequency designed to be heard through fog. Selecting the horn's frequency is all about knowing and working with the intended application, much like other designs it revolves around the application. Simply to say sound like an air horn comes up just a little short.

Ron

 

I've used Floyd Bell for unusual piezo-based sounds before.

https://www.floydbell.com/learn/tone_types.php

Whelen Engineering has both premise and automotive "air horn" sounds but they're not small or inexpensive.

http://www.whelen.com/mass/tones

http://www.whelen.com/auto/sirentones.php

Mallory has some medical specification tones that are lower frequency and perhaps closer to what you need. I assume these require a larger than typical transducer (~2").

http://www.mallory-sonalert.com/BasicSounds.aspx

 

I think the problem you will have is most people understand what an air horn sounds like, we have all heard air horns on trucks and trains as an example. The problem being an air horn on a truck does not have the same sound as an air horn on a train

The difference is because the sounds are a "chord". Trucks usually have two notes and trains have three or four notes

 

Thanks to everyone for all the replies. I realize I should have been more specific. Below is a picture of the type of air horn that we're trying to emulate. Here is an mp3 of the sound (originally found on this page). I thought I knew what it sounded like from memory, but now that I listen to it more closely maybe playing back an actual recording is the only way we're going to be able to get close to it.

 

As per my post #9 sound originates from a tuned horn instrument, this is why it is difficult to get the required frequency from a button type device.
Max.

 

You might try taking the horn off one of these and driving it with a small speaker.

Bob

 

i would recommend buying a sound chip module or replicating the circuit requirements of it in the form required , then adding a small 20w single chip amp , it is simple , can use low power , but give a decent sound output

The real cost as always will be the speaker , and with any longer usage the battery ,
Getting the voltage required from the 3v or 9v for louder amp , will require an increase in voltage and using a DC to DC converter to power the amp pcb would suit


Getting the sounds is as easy as doing a google for the sound effects there are lot out there that are license free and for common sounds such as air horns , train sounds , the speed of which it is played can allow for a variation as well

Cost can be reduced by using a small mono 5w amp chip if needed

sound module
https://www.ebay.com.au/itm/WT588D-...ni-USB-Interface-Voice-Sound-Module-5V-WT588D
/322493258778?hash=item4b16189c1a:m:mIEay6GH1Ov1oRJnU4w4Fdg

amp
https://www.ebay.com.au/itm/182320924235

dc- dc converter for amp pcb power
https://www.ebay.com.au/itm/MT3608-...471216?hash=item1ca6db4130:g:93kAAOSw5cRZIVIr


if you want a cpu selecting the sounds it can be done also - just interface the modulo on the keys point or redesigning using the chip directly and preload the flash chip directly using a spi programmer

pretty simple stuff

cheers


Y

 

An actual air tank surrounding an actual air horn would be the very loudest by far. And only a thin air line to keep the tank pressurized. A lot depends on how long the sound needs to last, and how portable it has to be.Liquid propane will provide about 300PSI at normal temperatures, carbon dioxide will provide about 600PSI at the same reasonable temperatures.That is about the most noise per cubic inch that I can suggest.

 

https://www.ebay.com.au/itm/Hot-10s...255981?hash=item4d6ebb626d:g:HfIAAOSwstNaxtiO

less flexable option , as you need to record your own sound on each
, beef up the amp and speaker ,and power for the amp

done quickly and these board can be purchased in bulk from online suppliers in china