Creating FM Radio Station using Raspberry Pi

This tutorial is for creating your own FM Radio station using FM Transmitter code and a copper wire.

Equipments Required

• Raspberry Pi 2/3/4
• Micro SD Card (minimum 16 GB)
• Standard Power supply
• A copper wire (1 metre long)
• Internet connectivity (Wifi/ Ethernet cable)

Before starting the tutorial, you'll need to understand Copper wire will be hooked up in GPIO pin no 4.

Below diagram will help you identifying the pin.

or you can read about it thoroughly with this link.

The wire will act as an antenna. But please note that the sound quality and frequency range will not be best. It'll work in small range like a small office or home

Starting up

1. Update your Raspberry Pi
   
   sudo apt-get update
   
   sudo apt-get upgrade
2. Installing package for setting up the Radio Station
   
   sudo apt-get install -y sox make gcc g++ git alsa-utils libmp3lame-dev
3. Now, once this package is installed, we can clone FM Transmitter library. This uses the general clock output to produce frequency modulated radio communication. It reads mono and stereo files, data from stdin.
   To clone this, use following commands
   
   cd ~
   
   git clone https://github.com/somu1795/fm_transmitter.git
4. Now moving to the directory and running make command
   
   cd ~/fm_transmitter
   
   make
5. Now running this
   
   sox /home/pi/fm_transmitter/star-wars.wav -r 22050 -c 1 -b 16 -t wav - | sudo ./fm_transmitter -f 100.3 -
   
   Defining the above arguments
   -c : Defining number of channels
   -b : Bit rate of output
   
   You can change this frequency according to your requirement.

Adding Support for MP3 files

1. Clone x264 support. This will be required to compile FFmpeg (command line tool will converts audio and video formats)
   
   cd /usr/src
   
   sudo git clone git://git.videolan.org/x264
   
   cd x264
   
   sudo ./configure --host=arm-unknown-linux-gnueabi --enable-static --disable-opencl
   
   sudo make
   
   sudo make install
2. Once the above commands are run, we will run following commands for compiling FFmpeg
   
   cd /usr/src
   
   sudo git clone git://source.ffmpeg.org/ffmpeg.git ffmpeg
   
   cd ffmpeg
3. Version specific commands ( Please see which version of Pi you have and install the command as per your requirement )
   
   Raspberry Pi 3 and later
   
   sudo ./configure --arch=armv7-a --target-os=linux --enable-gpl --enable-libx264 --enable-nonfree --extra-cflags='-march=armv7-a -mfpu=neon-vfpv4 -mfloat-abi=hard'
   
   Raspberry Pi 2 and before
   
   sudo ./configure --arch=armel --target-os=linux --enable-gpl --enable-libx264 --enable-nonfree
4. Now running below commands
   
   sudo make -j4
   
   sudo make install
5. As FFmpeg is now compiled and setup we can now run MP3 files.
   
   cd ~/fm_transmitter
   
   sudo python ./PiStation.py -f 100.3 bahubali.mp3

Please note there are rules and regulations for broadcasting FM Frequencies. Please check the laws of your country before transmitting the signal to any frequency.