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This library is about controlling an FM radio chips by using an Arduino 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 mathertel/Radio repository on 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 and maybe more.

See also the Changelog.


The API documentation for the libraries in DOXYGEN style can be found at

A more detailed article is available at

Currently the following radio receiver chips are supported:

  • The RDA5807M from RDA Microelectronics
  • The SI4703 from Silicon Labs
  • The SI4705 from Silicon Labs
  • The SI4721 from Silicon Labs
  • 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


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.
  • TestSI4705 to test the SI4705 chip.
  • TestSI4721 to test the SI4721 chip.
  • TestTEA5767 to test the TEA5767 chip.

The examples can be used with several chips:

  • The SerialRadio example needs only an arduino and uses the Serial in- and output to change the settings and report information.
  • The ScanRadio is similar to the SerialRadio example but includes some experimental scanning approaches.
  • The LCDRadio example is similar to SerialRadio but also populates some information to an attached LCD.
  • The LCDKeypadRadio example uses the popular LCDKeypad shield.
  • 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.

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