How to Make an FM Transmitter

If you're interested in radios, you can build an FM radio transmitter. A transmitter is exactly what it sounds like: a device that broadcasts radio signals, usually accompanied by an antenna. If you want to build a transmitter in your home, you don't need much high-tech equipment. And even if you aren't the most tech-savvy person, building your own FM transmitter is relatively straightforward.

Things You'll Need
1.2 sheets of one-sided copper board
2.Scissors
3.Hobby glue

Instructions
1.Cut out a rectangular piece of your copper board (about 3 X 5 inches), and then cut out five small squares from another piece of copper board (about 1/2 inch on each side of the square).

2.Glue the squares to the board, copper side up, with your hobby glue. These will act as the ground. Make sure there is at least 1/2 inch of space between the squares.

3.Solder the red wire on your 9-volt battery connector to one of the squares, and solder the black wire on your connector to the board itself.

4.Cut the end off of a standard audio cable, making sure that you still have the end with the audio input jack. Cut the cable so that it's about 4 to 6 inches in length.

5.Strip about 1/2 inch off of the audio cable (the end where you cut it) to expose the red and white wires. Solder the red wire to one of the squares and the white wire to the board itself.

6.Solder one end of your 470-ohm resistor to the pad with the 9-volt battery wire, and solder the other end to an empty square.

7.Solder one end of your 27,000-ohm resistor to the pad with the 470-ohm resistor, and solder the other end to the board.

8.Solder one end of your 10,000-ohm resistor to a free square and the other end to the board.

9.Wrap your length of wire tightly around the tip of your pen or pencil to form a coil. Solder one end of the coil to the square with the 9-volt battery wire and the other end to the remaining square.

10.Plug in your 9-volt battery, and insert the audio jack into the port on any audio player.

Tips & Warnings
All of the components needed to make this transmitter are available from your local electronics store.

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