What is it?

Today, thanks to the continuously growing system integration level of the chips, the making of high quality electronic devices, becomes easy as children play. Another factor helping this is the wide spread of different open source microcontroller development platforms, with plenty of created by electronic enthusiasts libraries, available for free download in Internet. Years ago, to make a nice FM receiver, a lot of experience was required. Such circuit needed few resonant circuits, for which tuning a special equipment was required. Now, when the implementation of complicated digital on chip filters is standard routine, the FM radio circuits become more and more simple - only one chip and few supporting devices perform the whole task.

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. A radio project based on TEA5767 chip can be found here. 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 FM radio design, also sold in Tindie, but I wanted to create more flexible and modern Arduino controlled FM radio, which can be used also as evaluation board for Arduino based projects.

What makes it special?

It is very tiny board whit high quality sound produced. It can be used for DIY projects, for learning purposes. Under desire I could supply the board as DIY hobby kit - can be used for learning how to solder different electrical parts, how to program sketches for Arduino, Pinguino and other microcontroller platforms.