random Sound Box

[zondan]

Hi,

(sorry for my bad English, i try my best)
for my other Hobby (Horror) LARP I want to build (or buy) some Sound Boxes.
(nothing is really fix)

I thought about a Box I can hide in the woods, a ruine, a building
The Box makes random sounds like footsteps, an opening door, breaking branches, shooting, explosions, screaming people,  ...
I thought about an USB-Stick or SD-Card with the mp3-Files for the sounds
a small megaphone for the sound
and some NiMH-AA or LiFe-18650 accumulators for the power (maybe a Pb-Cell)

my main problems are "it must be easy to use", "it must be save", "max 30$ each"
the Gamemaster mostly have not much time to react to the Players so it must be easy and quick to use.

I thougth about a µC doing all the stuff, but reading the file system and decoding the mp3 might be to much for it.

I found some sides about file system reading and mp3-decoding
but time is short, i only have till Jan, 2, 2016.

So I hope someone has/knows an (µC-)mp3-Player I can adapt for my needs.

I want a loudness of a screaming human, a battery stand time of >12h (with max 10% of the time sound output)
I don´t need the best sound quality

Some wishes I want to include later (maybe with a new start):
Triggers (a ripping string triggers the sound of an explosion to simulate.
Wireless-Control

[boffin]

Would this do the job?
https://www.adafruit.com/products/2133

[McBryce]

Wouldn't it be easier and cheaper to use a cheap Chinese MP3 player with a small amplifier and control the buttons from a small µP circuit?

McBryce.

[Fungus]

I thougth about a µC doing all the stuff, but reading the file system and decoding the mp3 might be to much for it.

I found some sides about file system reading and mp3-decoding
but time is short, i only have till Jan, 2, 2016.

So I hope someone has/knows an (µC-)mp3-Player I can adapt for my needs.

You can get mp3 modules which do all the storage/decoding. One of those with Arduino will do what you need. Putting it together with batteries, etc. will need a bit of electronics know-how.

http://www.ebay.com/sch/i.html?_nkw=arduino+mp3+player+module

Read the chip datasheets carefully, make sure they do what you think they do. eBay advertisers tend to put all sorts of buzzwords in the adverts which aren't true (eg. all of them say 'mp3' but not all of them will decode MPEG-2 Audio Layer III data).

You probably don't want the very cheapest modules. It's definitely worth spending a day or two on forums which are dedicated to this to find out what they recommend, eg. http://forum.arduino.cc/index.php?board=8.0

I want a loudness of a screaming human

That part might be tricky with battery power.

[zondan]

Thanks for your answers!

Would this do the job?
https://www.adafruit.com/products/2133

thanks, nearly exact, what I was looking for. I will look for a supplier for Germany. (a bit cheaper or open source and it would be perfect)

Wouldn't it be easier and cheaper to use a cheap Chinese MP3 player with a small amplifier and control the buttons from a small µP circuit?
McBryce.

Yes that was my first idea, but i hoped for something  more elegant.

You can get mp3 modules which do all the storage/decoding. One of those with Arduino will do what you need. Putting it together with batteries, etc. will need a bit of electronics know-how.

http://forum.arduino.cc/index.php?board=8.0

Thank you, I will read this!

I want a loudness of a screaming human

That part might be tricky with battery power.

I know. So I had the idea with the (oh, I forgot to write it) megaphone. I found a small one with 5W an 105db (ok not really human screaming, but safety first), maybe i can adapt this to work on a headphonejack.

I also found a projekt with an atmega and a VS1011b http://www.mictronics.de/projects/mp3stick-mp3-player/

I will read all of this and the look for the best way for me.