This ESP32-Based Internet Radio Is as Simple as They Come
Vedran’s Internet radio and Bluetooth speaker comes in a small form factor with a minimalistic user interface.
We all have different requirements for our home audio systems. If you’re an audiophile, you probably won’t be happy with anything less than lossless audio files, a high quality DAC, an amplifier that costs more than a used Honda Civic, and speakers made by a German company with an unpronounceable name. Most people, however, are happy with static-free output and easy access to streaming internet audio and a Bluetooth connection. If you fit into the latter group, Vedran’s ESP32-based Internet radio and Bluetooth speaker is as simple as they come.
This self-contained audio system has just two functions: to stream internet radio streams and to play music from your smartphone over a Bluetooth connection. Essentially, it’s a Bluetooth speaker with the addition of “smart” streaming that can be done without requiring a connection to your smartphone or anything else. Both of those functions are handled by a single ESP32 board. You will need the upgraded WROOM ESP32, which has more flash memory (16MB) to handle the large size of the binary that contains the code for internet radio and Bluetooth. If you only want to use one of those two functions, you can stick to a normal ESP32 with 4MB of flash memory.
The ESP32 sends digital audio data to a DAC (Digital-to-Analog Converter) over I2C. The DAC is capable of outputting 24bit audio, while the ESP32’s built in DACs can only handle 8bit audio. The DAC, in turn, outputs to a HXJ8002 amplifier. That is only capable of a single 3W channel, so you may need to upgrade to something like a 20W Class D amplifier if you want stereo output or more volume. Power is provided by a lithium-ion battery through a TC4056 USB charger circuit. One 3.3V buck converter is used for the ESP32 and the DAC, while a second 5V buck converter is used for the amplifier. A rotary encoder is used for control, and everything is housed within a 3D-printed enclosure that is wrapped in red fabric with an attractive texture. The total build cost for this project should be under $50, which is a great value for a stereo with the features this integrates.