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Alarm MP3 & chips and hardware

Hi,

I'm working on a homebuilt circuit, that will provide an anti-theft
alarm for a bicycle.

I've been going down the routes of looking at various 555 timer
circuits, making various beep beep noises, but prefer the sounds of
some of the free mp3 sound files that are out on the net.

I've downloaded some of these files, and am wondering how I could put
them on a memory chip of some type, and then be able to 'output' them
at appropriate times, into a loud speaker..

Clearly, I'd need a chip to interpret the files held on the ROM chip
(?), before it's output to the speaker? What would that chip be? Are
there any off the shelf chips to do this sort of thing?

Sorry, I can't be more specific, as I don't know too much about
electronics.

Thanks
Jeremy Watts
 
Hi Jeremy,

There are a bunch of ways to do this, but since you say you're somewhat
inexperienced in electronics I'd try one of these:

http://www.ebay.com/itm/10s-10-Sec-Sound-Voice-Recordable-Module-Chip...

There are special purpose ICs that they crank out by the millions for
"Obama Birthday Greetings" cards, etc - that's what's under the little
blob on the board.  You can ditch the switches and wire up your own
speaker and amp for the alarm, record in your sound, and rig up your
trigger circuit to the board's terminals in lieu of the playback button.

Shipping from China might take a week or two, but for a buck you can
hardly go wrong.

Cheers
 
H

hamilton

Jan 1, 1970
0
I'm working on a homebuilt circuit, that will provide an anti-theft
alarm for a bicycle.

Sorry, I can't be more specific, as I don't know too much about
electronics.


OK, you want to "build" your own device.

If you really want to do that, you need to do more homework.

As a starting point:
1) learn what an MP3 file is.
2) learn about solid state storage devices
3) learn about how to program a device that will take advantage of the
devices in 1 & 2.

Let me help you out:

http://lmgtfy.com/?q=build+mp3+player

with About 73,600,000 results (0.14 seconds)

you should be able to see what needs to be done.
Thanks
Jeremy Watts

Your Welcome

PS: Second link will tell you every thing you need to know.
 
L

linnix

Jan 1, 1970
0
Hi,



I'm working on a homebuilt circuit, that will provide an anti-theft

alarm for a bicycle.



I've been going down the routes of looking at various 555 timer

circuits, making various beep beep noises, but prefer the sounds of

some of the free mp3 sound files that are out on the net.



I've downloaded some of these files, and am wondering how I could put

them on a memory chip of some type, and then be able to 'output' them

at appropriate times, into a loud speaker..



Clearly, I'd need a chip to interpret the files held on the ROM chip

(?), before it's output to the speaker? What would that chip be?

mp3 decoder.
Are there any off the shelf chips to do this sort of thing?
Yes.




Sorry, I can't be more specific, as I don't know too much about

electronics.

But you need to know the trade-offs. MP3 is Discret Fourier Transform (DFT) of time domain samplings, so you need to reverse the transform before outputting to the speaker. Storing/outputting the real time audio samples might be easier, but it would take more than 10x memory storage.
 
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