There is a lot of "FM BUG" out there. to using them a FM radio (or a radio receiver) is needed. In this instructable I'm gonna show you how to build a digital BUG that you can use it with your phone or laptop.
Step 1: What You Need:
1. A bluetooth handsfree.( no need for fancy expensive one. you can use a cheap fake old ! one. look at you old stuff ,must find one!!)
2. phone battery.
--that's all. also some tools like soldering iron may needed.
Step 2: Teardown It!
Open bluetooth handsfree, and detach battery, airphone, charging socket etc. except mic!
Step 3: Connect Battery
Solder 2 wire to handsfree's battery pins and conncet them to phone battery. connect red wire to '+' pin and black wire to '-' pin.
Step 4: Pair With Laptop
search "bluetooth devices" in start menu. click on add new device. hold the key on your bug for 20 sec. pair it with your pc.
search "sound" in start menu, click on recording tab. choose bluetooth headphones. In new window go to "listen" tab and check "listen to this device". click OK.
It's done, and now you should hear audio from your laptop. Enjoy!