ESP32-S3 internet radio: code and schematic

ESP32-S3 Internet Radio: Circuit, Code, and Web Interface

ESP32-S3 N16R8 with UDA1334 DAC lets you build a minimal internet radio in an evening. The project uses I2S for audio output, SSD1306 OLED display for status, and a web interface for station management. It supports switching preset streams and entering custom URLs.

Components and Wiring

Required components:

• ESP32-S3 N16R8
• UDA1334 DAC for MP3 decoding
• Amplifier with speakers (soundbar)
• Dupont wires

Optional: 0.96" I2C SSD1306 OLED.

Wiring UDA1334 to ESP32-S3:

| ESP32-S3 | UDA1334 |

|----------|---------|

| GPIO41 | BCLK |

| GPIO42 | WSEL |

| GPIO45 | DIN |

| GND | GND |

| 3V3 | 3V3 |

Wiring OLED SSD1306:

| ESP32-S3 | SSD1306 |

|----------|---------|

| GPIO21 | SDA |

| GPIO20 | SCL |

| GND | GND |

| 3V3 | 3V3 |

Power: USB splitter from a 100W power supply. ESP32 and amplifier are powered in parallel.

Main Project Code

Full code in a single .ino file. Libraries: WiFi, HTTPClient, Audio, Adafruit_GFX, Adafruit_SSD1306.

#include <WiFi.h>
#include <HTTPClient.h>
#include <WebServer.h>
#include "driver/i2s.h"
#include "Audio.h"
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

// WiFi settings
const char* ssid = "ssid";
const char* password = "password";

// I2S pins
#define I2S_BCLK 41
#define I2S_LRC 42
#define I2S_DOUT 45

// I2C for OLED
#define I2C_SDA 21
#define I2C_SCL 20
#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
#define OLED_RESET -1
#define SCREEN_ADDRESS 0x3C

Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

struct RadioStation {
  const char* name;
  const char* url;
};

const RadioStation radioStations[] = {
  {"RSJ", "http://stream.srg-ssr.ch/m/rsj/mp3_128"},
  {"Revma", "https://stream.revma.ihrhls.com/zc238"},
  {"Jazz Stream", "http://jazz.streamr.ru/jazz-128.mp3"},
  {"Paris Jazz", "http://parisjazz.ice.infomaniak.ch/parisjazz-high.mp3"},
  {"Smooth Jazz", "http://smoothjazz.cdnstream1.com/2619_128.mp3"},
  {"Jazz WR06", "http://jazz-wr06.ice.infomaniak.ch/jazz-wr06-128.mp3"},
  {"Jazz WR07", "http://jazz-wr07.ice.infomaniak.ch/jazz-wr07-128.mp3"},
  {"Jazz WR10", "http://jazz-wr10.ice.infomaniak.ch/jazz-wr10-128.mp3"}
};

const int radioStationsCount = sizeof(radioStations) / sizeof(RadioStation);

int currentStationIndex = 0;
Audio audio;
int currentVolume = 18;

I2S is initialized for UDA1334. The display shows WiFi status, station name with scrolling text, and a volume indicator.

Web Management Interface

Server on port 80 serves an HTML page with:

• List of preset stations (click to switch)
• Volume slider (0-21)
• Fields for custom station (name + URL)
• Status of current station and IP address

Key endpoints:

• /change?station=N — switch station
• /volume?value=N — set volume
• /custom?name=NAME&url=URL — custom station

HTML is generated dynamically with CSS styles and JavaScript for AJAX requests.

OLED Display Output

Display updates every 100ms:

• Top line: ONLINE/OFFLINE
• Scrolling station name (scrolls if overflow)
• Volume as number and bar

void updateDisplay() {
  display.clearDisplay();
  // WiFi status
  bool wifiConnected = (WiFi.status() == WL_CONNECTED);
  display.setTextSize(1);
  display.setCursor(0, 0);
  display.println(wifiConnected ? "ONLINE" : "OFFLINE");
  // ... remaining logic
  display.display();
}

Key Points

• Minimalism: One .ino file, ready-to-use Audio and Adafruit libraries
• I2S + UDA1334: Full MP3 decoder without overhead
• Web Control: Management without extra hardware, IP displayed on screen
• Custom Streams: Arbitrary URLs via form
• Stability: Runs on 100W USB power without resets

Enhancement Recommendations

• Optimize power: separate regulators for ESP32 (3.3V/1A) and amplifier
• Add GPIO buttons for local control
• Implement state saving in NVS (last station, volume)
• Support FLAC/OPUS via Audio library update
• Enclosure with soundbar mounting

Project is suitable for prototyping. Scaling requires code refactoring and PCB design.

— Editorial Team