Look at newer project, called FmStick. Its digital USB-FM Transmitter
This is application to control si471x FM transmitter IC
Hardware options:
- i2c interface (through i2c-tiny-usb).
- Up to 1W power output.
- Analog or SPDIF audio input.
Software options:
- sending RDS time every 5 seconds
- telnet interface to update RDS and transmitter parameters
- auto-detect chip firmware (supported RDS or not).
Block diagram:
Schematic diagram:
Board:
Archives:
Source code avaliable here: si471x.tar.gz
Schematics (by Eagle) and libraries: SI4711-pcb-sch_tar.gz