RN-52 Bluetooth Hookup Guide
Joel_E_B 
Streaming Tunes
Enough talk. Let's stream some tunes! The RN-52 comes ready to begin streaming tunes from most any Bluetooth audio-capable device. However, to add external control functions such as play, skip, and volume, you'll need to make a few small adjustments.
Hardware
Using the same setup from the Hardware Setup section, let's add a few more pieces. By connecting a few buttons and some speakers, the RN-52 becomes a full-on music station and remote. The image below shows all the connections and the functions of each button.
The functions for each GPIO can be found in the datasheet.
Configuration
By default, the RN-52 does not have the AVRCP enabled. This is part of the extended features. When you type D to see the basic settings, you'll notice a line that says ExtFeatures=XX, where XX is some hex value. As of this writing, the default firmware comes with the AVRCP buttons disabled. Future versions of the firmware may differ. Looking in the Command Specifications document, we find this table:
Notice that bit 0 is the bit we need to enable to activate the AVRCP button functionality. Send the command S%,07(/r) to enable this bit while leaving the other two bits enabled. Then follow it up with a reboot -- R,1(/r). You should now have AVRCP enabled. Type D to double check the settings.
That's really the only setting that needs changed for this example.
Connect and Play
You are now ready to connect to your Bluetooth device and start streaming some music. Directions on how to pair and connect to the RN-52 can also be found in section 1.4 of the user guide.
*Note: The quality of the audio will depend on which speakers you've attached. Testing the RN-52 with two 8Ω stereo speakers worked great. However, without external amplification, the volume needs to be cranked up to achieve normal indoor volume. If you're not satisfied with the volume, an external amp can be connected to the speaker pins. We recommend using the Audio Amplifier Kit.