What is it?

This FM radio is based on the RDA FM chip RDA5807M. Normally it is sold directly as FM radio module. These modules are pin compatible with the widely spread TEA5767 (Philips) modules. Both chips use I2C communication with the microcontroller, which sets the different internal registers of the chips, and in this way controls the FM radio receiver chip. The advantages of the RDA5807M chip compared with TEA5767 are following:

• It requires less external components
• It has embedded audio power amplifier, which can be loaded with 32 Ohm speakers.
• It has bass boosting function

Its disadvantage is is the narrower power supply range - the maximum supply, which can be used is 3.6 V - when supplied by Arduino will require 3.3 V voltage regulator.

Why did you make it?

I had an old TEA5767 design, which can be found also in Tindie in my store. Now I wanted to try the performance of the RDA chip. In parallel with this I was interested in the creation of stereo active audio mixer, with two channels - one for the signal of the radio, second for the signal of some other audio source. Based on these requirements, the new design was born.

What makes it special?

It combines all advantages of mini Arduino FM evaluation board, in combination of high quality active audio mixing device.