Tired of listening to the chatter of DJs and want to broadcast your own radio station? Do you need a quick and easy solution to stream MP3 or internet radio to your archaic car stereo?
Once again, this Raspberry Pi comes to your rescue with its previously unknown FM broadcasting capability.
Before proceeding, please understand that this is a proof of concept design. If you are not licensed, you must not broadcast on the FM band and you do so at your own risk.
What You’ll Need for Your Pi FM Project
Start by downloading the PiFM image, which you will need to flash onto your SD card. You can use the PirateRadio.py script if you like by installing it into your existing Raspbian installation. but this tutorial focuses on the PiFM image.
You will also need a jumper wire, a soldering iron and solder and a length of 2mm wire cut to 20-30cm. I used an old hanger left over from the HDTV digital antenna project. but you can buy 2 mm wire in rolls in electronic stores; some may even cut it for you. While you’re at it, buy some heat shrink tubing that’s the right size to put on the jumper.
You may also need some Sugru or similar putty. to secure the antenna, or possibly the glue gun. When everything is assembled, it’s time to assemble the project.
Finally, you will need a Linux computer other than your Raspberry Pi.
But first, an important question…
How does a small computer become a radio transmitter?
In order not to interfere with other devices, the Raspberry Pi uses a technique known as spread spectrum. This reduces the impact of the processor on nearby equipment (by spreading EMI over a wider bandwidth to reduce interference), but the side effect of this is a GPIO array that can be used to broadcast on the FM band!
You can use this broadcast power by connecting an antenna to pin 4.
Now, as you know, we are not lawyers. We . So before proceeding, be aware that in the vast majority of countries, broadcasting on the FM band without a license is illegal and can lead to problems with fines and jail time.
Building your own antenna
The most difficult aspect of this project is assembling the antenna, but if you have the right equipment, you should be able to do it in about 10 minutes. With the jumper notched about 10mm of the stripped wire above the connector, continue soldering it with the 2mm wire.