How to Build a Tiny FM Radio Transmitter With an Arduino for Under

Building your own miniature FM radio transmitter using an Arduino is a fun electronics project that can be completed on the cheap. With just a handful of components, you can broadcast your own music or voice over any standard FM radio within about a 50-foot radius.

What You'll Need

To build a tiny FM transmitter with an Arduino, you'll need the following parts:

That's it for required components! Optional extras could include a small amplifier or outdoor antenna for increased range. But the parts above are all that's needed to get your micro FM transmitter up and running. The total cost is under $5, assuming you already have an Arduino available.

Circuit Design

The circuit for this DIY FM transmitter is very straightforward.

We simply need to:

Here is a circuit diagram showing how everything needs to be connected:

We'll use the Arduino's TX pin (pin 1) to feed audio data to the transmitter module's data pin. The Arduino and transmitter module should share a common ground.

A breadboard makes it easy to plug everything together. Jumper wires connect the modules to the Arduino's TX pin and ground pins.

Code

With the circuit wired up, we need to upload code to the Arduino to generate the FM audio signal.

Here are the key steps in the Arduino sketch:

The full code for the Arduino FM transmitter is available on GitHub. You can tweak the code to modify the broadcast frequency or audio being generated.

Upload the code, and you're ready to broadcast!

Building the Antenna

A wire antenna helps extend the range of the transmission. The antenna should be about 20cm long. Strip both ends of the wire and twist the exposed ends.

Connect one end of the wire to the antenna/ground pins on the transmitter module. The other end can dangle freely. Positioning the antenna vertically will give the best results.

Testing and Using Your DIY Transmitter

Once everything is assembled, give your Arduino FM transmitter a test!

Power on the Arduino, and tune any nearby radio to the frequency specified in your code, such as 107.0 MHz. You should suddenly hear your audio broadcast emitting from the radio's speakers!

The broadcast range is roughly 50 feet for this little DIY transmitter. Outdoors or with an upgraded antenna, you can extend the range. Just stay within legal transmission power limits.

To use your micro FM station long-term, you could:

So there you have it - with about $5 of parts and some simple Arduino code, you can set up your very own miniature FM radio station for endless DIY broadcasting fun!