I want to buy FM transmitter such as this one. Is it possible to communicate with the transmitter from Android device using Android API? change freq. etc.
If not - Is there any FM hardware that can communicate with android API? Thanks.
The Android device can communicate with the FM transmitter via the USB. See USB Host Documentation.
Another alternative is to connect the FM transmitter to a micro-controller, or a ready kit like Arduino, which is also connected to a Wi-Fi or Bluetooth module, then communication would be occurred through that channel.