Creating a wireless speaker requires a few pieces of hardware. First, you need something that can connect to Wi-Fi. Then, you need a digital-to-analog converter (DAC) capable of faithfully reproducing music-grade audio, and you need an amplifier to drive the speakers. Coming soon, with the help of the ESP32 Audio Development board from Sonocotta, you can build your own wireless speaker system.
Andriy Malyshenko has a background in IT with a passion for embedded electronics and is the person behind Sonocotta. Malyshenko started with a project to retro-cycle a vintage analog AM radio. Retro-cycling is when you repurpose a vintage device with modern technology. In this case, the project evolved into a general-purpose audio development board that you can use in your Wi-Fi-related audio projects.
Two development boards are coming: full size and a mini version. Both boards feature an ESP32 module running at 240 MHz with 16 MB of flash and 8 MB of PSRAM. Two Maxim MAX98537 ICs provide stereo audio. These chips are a digital pulse-code modulation (PCM) based class-D amplifier that can deliver 3 watts into a 4 ohm load. This chip supports a wide variety of audio input formats, including I2S, which this development board uses. Additionally, there is a charging circuit for an optional LiPo battery.
The full-size module adds a 2.8" 320x240 TFT touchscreen. One potential use would be configuring settings or selecting music. Another input is an IR receiver for remote control, and another is headers for joystick (or rotary encoder inputs.). The board also has an SD card socket and a JTAG header. Sonocotta says this version of the ESP32 audio development board fits inside of a Raspberry Pi 4 case.
Malyshenko has a practical example for the mini audio development board. The build shows the dev board running inside a laser-cut box. Add a battery, and you have a portable wireless speaker!
Schematics for the boards are available in this GitHub repository. Or, if you are interested in the ready-made modules, sign-up for the Crowd Supply campaign. The pre-launch form will help Sonocotta gauge interest and estimate costs for a manufacturing run.