New cool phone gadget has been sighted

This is an ear plug with build-in microphone. It detects sound waves comeing from inside instead of coming through the mouth. Pretty cool.

think-a-move.com/products.html

Guess it makes sense, I seem to remember from school that you can make a microphone into a speaker and vice versa by reversing the current…is this related?

I think those guys have multiple microphones in the ear plug as well as a speaker. The new thing is the way it detects sound. Plus if you use the same speaker as a microphone, it would be hard to do 2-way talking. While you are talking, the other party really needs to shut.

Sorry I meant that perhaps they were using the ear drum as a reverse speaker, i.e. microphone.

I think those guys have multiple microphones in the ear plug as well as a speaker. The new thing is the way it detects sound. Plus if you use the same speaker as a microphone, it would be hard to do 2-way talking. While you are talking, the other party really needs to shut.[/quote]

No idea how this product actually works, but the idea brought up by the two of you (though you both aren’t convinced) actually should work. The microphone and the speaker can be one electromechanical unit (probably a piezo). You do not need separate items. And you can use it in both directions simultaneously. The speaker knows exactly what current it is supposed to output. Any difference to the current actually delivered is due to impinging sound and mechanical resistance. To get that difference, a signal processor can just subtract out the signal it knows it is supposed to be outputting; this assumes linearity of the entire system.