Making the "FM Bug" circuit board
Secret agents in movies often listen in on conversations with hidden microphones. You can make your own "spy bug" that will transmit audio through a FM transmitter. The procedure requires a few parts from an electronic supply store and a fair amount of experience in using a soldering iron on small electronic parts. You will be able to pick up what is being said from your spy bug using a regular FM radio from quite a distance away.
Instructions
1. Put some newspaper down on a table. Use the utility knife to cut out all of the holes of the perf board. Sand down the side of the board where you cut the holes with sandpaper.
2. Put the perf board down on the newspaper. Insert the two contacts of the 1M resistor into the holes. Turn over the board. Apply solder to each of the two contacts. Crimp the solder with the needle nosed pliers. Turn over the board.
3. Insert the contacts of the 47K resistor into the holes. Turn the board over and solder the two contacts. Crimp the solder with the needle nosed pliers. Turn the board back right side up.
4. Insert the two contact pins of the 22K resistor into the perf board. Turn over the board. Solder the two contacts to the board. Cut off the contact pins with the needle nosed pliers. Turn over the board.
5. Insert the two pins of the 10K resistor into the perf board. Turn over the board. Solder the two contacts to it. Crimp the contacts with the needle nosed pliers. Turn over the board.
6. Insert the two pins of the 470R resistor into the perf board. Turn over the board and solder the two pins to it. Crimp the contacts with the needle nosed pliers. Turn over the board.
7. Insert the two pins of the 1n ceramic capacitor into the perf board. Turn over the board and solder the two pins to it. Cut off the contact pins with the needle nosed pliers. Turn over the board.
8. Insert the two pins of the 5pc ceramic capacitor into the perf board. Turn over the board and solder the two pins to it. Cut off the contact pins with the needle nosed pliers. Turn over the board.
9. Insert the two pins of the 22n ceramic capacitor into the perf board. Turn over the board and solder the two pins to it. Cut off the contact pins with the needle nosed pliers. Turn over the board.
10. Bend over the two pins of the 100n monoblock. Insert the two pins of the monoblock into the perf board. Turn over the perf board and solder the two pins to it. Cut off the contact pins with the needle nosed pliers. Turn over the perf board.
11. Put the perf board down on the newspaper. Push the two contacts of the electroset microphone into two holes on the side of the perf board. Apply solder to each of the two contacts. Solder the two contacts of the 5-turn coil to the two contacts of the electroset microphone.
12. Cut three 4-inch pieces of electric wire with the wire cutters. Strip the insulation off both ends of the wires with the wire strippers. Solder one end of one wire to the positive contact on the monoblock on the perf board. Solder the other end to the positive contact on the 9 volt snap.
13. Solder one end of another wire to the negative contact on the monoblock on the perf board. Solder the other end to the negative contact on the 9 volt snap. Solder one end of the third wire to one of the contacts of the 5-turn coil on the perf board. Leave the other end of the wire free to act as the antenna.
14. Cover the perf board with a piece of black electricians tape. Cut a small piece of foam core with the utility knife. Wrap the foam core around the perf board. Apply heat with a heat gun to melt the foam core onto the perf board.
15. Insert a 9 volt battery into the 9 volt battery snap. Your spy bug FM transmitter will now send audio to an FM radio for you to listen to once you tune the radio to the channel where the audio is playing.
Tags: perf board, Turn over, over board, Turn over board, needle nosed, needle nosed pliers