So, I was looking at sparkfun.com, which sells electronics for projects and such, and got an idea that I could make an accessory using something like this sew-on buzzer, but I don't know if it's even possible with Android. Bluetooth modules are pretty expensive, compared to something like a basic wireless transeiver or RF receiver. And if it can just pick up a signal, I'm sure it would be much easier than figuring out how to get it to pair.
I haven't done any Android programming yet (or prototyping for that matter), but I am familiar with Java, and I've wanted to get started in it for a while, but I don't know what the physical capabilities are (in my case, with a Droid Incredible). Is it possible to have an app transmit any kind of arbitrary signal, or only connecting to bluetooth devices and wireless networks?
And finally, sorry if this isn't the place to ask, I just wasn't sure and this seemed like the closest forum to ask what I wanted.