Few months ago, i have been looking for a robust easy FM broadcast solution, basically, i want simple solution, not the classic complex plan like > Stereo encoder = PLL = VCO = PA … < after some investigations i have found the NS73M FM Transmitter module from Niigata Seimitsu Co is a hight quality transmitter IC, can be controlled by a controller (via SPI/I2C), the features are:

87.5 – 108 Mhz Coverage
Stereo Modulation
Very Small package
I2C or SPI control
No tuning
Low Cost
…

The source of the project come from here and here

I have made 3 boards for this projects:
ArduiFM_Unit, its the main board with the NS73 and controller (Atmega328P)
BackConnector, the back board with input-sound, jack/RCA, and RS232 connector (future option for RDS)
Control_Cmd, is the front board with the button, up/down/backlight/set

The one of disadvantage have found is not RDS possibility because the sound is already modulated and mixed into the NS73, you cannot add signal.

right now, you can see the main µC board, LCD, audio connector, IHM board mounted, a DB9 connector is installed for a RDS future option. Now, the project need a power amplifier … stay tuned.