Complete instructions for this episode of Weekend Projects can be found at
http://makeprojects.com/Project/Covert+Listening+Book/2150/1
Connect an amplified listener with an in-car FM transmitter, and you’ve got a wireless bug. Place the circuit in a hollowed-out book with the microphone concealed by the dust cover, and you’ve got a super-sneaky covert listening device! Tune in via a FM radio receiver set to the correct frequency, and you’ll be able to hear through walls.
