Making Sound For The Blind

I wasn't sure where to put this but I figured since it wasn't really a FIRST thing, I'd post it in chit-chat. None the less...

A blind friend of mine is interested in spinning poi (fire spinning) but is having issues with doing tricks with poi that have streamers attached to them because they become tangled when spun and if we don't use the tennis balls, it is hard for him to pin point where they are in space. Thus, here is my question to anyone with any knowledge of electronics...

Does anyone know where someone could find a small device that could be programmed to make a sound (other then beeping) loud enough to be heard through a tennis ball but small enough to fit into the tennis ball itself? They have devices for the blind that make a contunious beeping sound that they use for baseballs and such so the blind know where they are but the sound is irritating as anything and we'd like to be able to immitate the sound of fire to get him used to hearing it for when we give him a pair of real poi that are lit.

If you're not sure what poi are or what I am talking about you can check out www.homeofpoi.com. What we are trying to make are practice poi, as any FYI.

Any and all ideas are welcome. Thank you!