This library is about controlling an FM radio chips by using an Arduino, ESP8266 or ESP32 board and some optional components like a LCD display, a rotary encoder, a LCD+Keyboard shield or an Ethernet Shield to build a standalone radio.

In the github.com/mathertel/Radio repository on github.com you find an Arduino library for implementing an FM receiver using one of the supported radio chips for receiving FM broadcast audio signals.

There are various examples included that show using the library using different hardware setups.

The library is working for many boards like Arduino, Arduino Mega, ESP8266, ESP32 and maybe more.

See also the Changelog.

The API documentation for the libraries in DOXYGEN style can be found at http://mathertel.github.io/Radio/html.

A more detailed article is available at www.mathertel.de/Arduino/RadioLibrary.aspx.

Currently the following radio receiver chips are supported:

• The RDA5807M and RDA5807FP with I2S support from RDA Microelectronics
• The SI4703 from Silicon Labs, now Skyworks
• The SI4705 from Silicon Labs, now Skyworks
• The SI4721 and SI4730 chips from Silicon Labs, now Skyworks
• The TEA5767 from NXP

They all are capable for receiving FM radio stations in stereo with European and US settings and can be controlled by using the I2C bus. However there are differences in the sensitivity and quality and well on receiving RDS information from the stations.

For each of these chips a specific library is implemented that knows how to communicate with the chip using the I2C bus and the wire library. These libraries all share a common base, the radio library so that all the common code is only implemented once in there:

All the libraries share the same interface (defined by the radio library) so it is possible to exchange them when not using one of the chip specific functions.

Currently the following radio transmitter chips are supported:

• The SI4721 from Silicon Labs, now Skyworks

Contributions to the library like features, fixes and support of other chips and boards are welcome using Pull Requests.

Please don't ask general programming questions in this project. Radio chip specific questions may be answered by the community (or not) and are closed after some months of inactivity.

Within the Arduino library you can find examples that implement different scenarios to control various radio chips.

The basic examples only startup the chips and set a static station and volume:LCDKeypadRadio

• TestRDA5807M to test the RDA5807M chip.
• TestSI4703 to test the SI4703 chip.
• TestSI47xx to test the SI4705, SI4721 and SI4730 chips.
• TestTEA5767 to test the TEA5767 chip.
• TransmitSI4721 to test transmission mode of SI4721 chip.

The examples can be used with several chips and boards:

• The SerialRadio example doesn't need extra inputs as it uses the Serial in- and output to change the settings and report information. This example can be used with Arduino, ESP8266 and ESP32.

• The LCDRadio example is similar to SerialRadio but also populates some information to an attached LCD. This example can be used with Arduino, ESP8266 and ESP32.

• The ScanRadio is similar to the SerialRadio example and includes some experimental scanning approaches. This example can be used with Arduino, ESP8266 and ESP32.

• The LCDKeypadRadio example uses the popular LCDKeypad shield for Arduino UNO only.

• The WebRadio example is the most advanced radio that runs on an Arduino Mega with an Ethernet Shield and an rotator encoder. You can also control the radio by using a web site that is available on the Arduino.

The only sending example for the SI4721 chip can be found in TransmitSI4721.