Here's an experience prototype of the Rumble platform, a project I'm developing for Hiroshi Ishii's "Tangible Interfaces" class at the Media Lab.

Basically, I take regular audio out of a Bluetooth headset, amplify it, and run it to a linear driver (component's name is "NXT exciter"). The bluetooth receiver and driver can be integrated into clothing, personal accessories, etc - for this demo, I'll be putting it into a bracelet.

When you're standing over a particular point of interest or opportunity, my Android app will play an audio file that tells you a little more about your location. For this demo, I'm having it tell you whenever you're standing directly on top of the Red Line on Boston's MBTA subway system.

The audio causes the NXT exciter to buzz or "rumble" a little, so it serves as a gentle, polite notification. However, you can get more detail if you press the bracelet to your forehead - doing this causes you to hear the audio file directly inside your head, through the magic of bone conduction.

Where, you ask, is basically the only place you can get NXT exciters? Heh heh heh. Here: tinyurl.com/yfsmmft

The very simple amp circuit is gratefully taken from here: reprise.com/host/circuits/lm386.asp