Sounds like you're describing The Thing[1]. It might work -- but then how could you tell cellphones apart? [1]: https://en.wikipedia.org/wiki/Thing_%28listeni

Sounds like you're describing The Thing[1]. It might work -- but then how could you tell cellphones apart? [1]: https://en.wikipedia.org/wiki/Thing_%28listening_device%29 https://en.wikipedia.org/wiki/Thing_%28listening_device%29