This module could modulate your voice on the FM radio wave.
And anyone with a radio device could receive it. Very easy to build a tiny radio station. A library for Arduino to work with this module is in download.
I2C interface 5V TTL compatible
Arduino plug and play
VCC Input: 3.0V ~ 3.6V
Arduino FM Module
Then connect the antenna. Any metal line about 75cm can serves as an antenna.
Download the libary and upload the example sketch to Arduino. Then open Serial monitor:
Tune your radio device and set it at FM 90MHz. Enjoy!