DIY Mini Web Radio

If you have a computer or smartphone, then you already have access to virtually every audio file ever recorded in human history. But lots of people don’t have smartphones or maybe they want a way to listen to streaming Internet radio on an affordable, dedicated device for some other reason. Those people should check out this tutorial to learn how to build a small and adorable Mini Web Radio.

After setup, AllanG’s Mini Web Radio can only do one thing: play the configured Internet audio source. To change the audio source, a user must pull up the self-hosted web interface on a separate computer or smartphone and then enter the new URL. Users only have control over the volume and the ability to turn the device on or off. Audio pumps out through a headphone jack and a small LED indicates when the power is on. The Mini Web Radio can receive power from a USB cable or a rechargeable battery.

The Mini Web Radio only requires a few components: an ESP32 development board like the Wemos Lolin32 Lite, a MAX98357A amplifier chip, a potentiometer with switch, an 18650 lithium-ion battery and holder, and a handful of resistors and other miscellaneous parts. The ESP32 has a built-in Wi-Fi adapter, which lets it connect to the Internet and download an audio stream. It sends the digital audio data to the MAX98357A chip via I2S. That chip both converts a digital audio signal to analog and amplifies it with a 3W Class D amplifier. The 18650 battery connects to the Lolin32’s onboard charging port.

The enclosure for the Mini Web Radio is printable on just about any 3D printer. It is a minimalist design and very pleasing to look at. It requires screws to mount the ESP32 board, but the cover snaps on to reduce the fastener count.