A pocket FLAC player that runs a Spotify-style UI on a $20 ESP32-S3

Plug in headphones and the music follows them. Unplug and it pauses, like a phone. The whole thing runs on a Freenove ESP32-S3 display board with a 2.8-inch touchscreen.

Build sheet

Board: Freenove ESP32-S3 Display FNK0104B
Display: 2.8in ILI9341 touchscreen
Audio: Built-in speaker, PCM5102 DAC
Language: C++ (Arduino)

Can I build this?Intermediate · AI 4/5 · $30–50

Difficulty: Intermediate
AI-buildability: 4/5
Time: A weekend
Cost: $30–50

Parts

Freenove ESP32-S3 Display FNK0104B PCM5102 DAC microSD card

Tools

Computer with Arduino IDEUSB-C cablesoldering iron

Starter prompt

Based on "A pocket FLAC player that runs a Spotify-style UI on a $20 ESP32-S3" on Afterware: https://afterware.xyz/p/a-pocket-flac-player-that-runs-a-spotify-style-ui-on-a-20-esp32-s3

Write Arduino firmware for an ESP32-S3 board with a 2.8in ILI9341 touchscreen and a microSD card. Scan the card for FLAC files, read their tags, and show an album list with a now-playing screen. Play audio through an I2S DAC such as a PCM5102, and pause playback when headphones are unplugged. Use LVGL 9 for the UI.

Estimates based on the original write-up. How AI-buildability is scored. Building with an AI assistant? Connect it to Afterware (free MCP server).

Story

onda plays FLAC files straight off a microSD card, through the board's speaker or through a PCM5102 DAC into headphones. The touch UI is modeled on Spotify and built with LVGL 9.5. Swipe up from the bottom edge for a control center with volume, brightness, battery and Wi-Fi. A tap can never push headphone volume above 75%.

The firmware is an Arduino sketch for the Freenove FNK0104B board. Turn on Wi-Fi and a web page lets you upload music, edit tags inside the FLAC files, fix covers and pull missing album data from MusicBrainz. Plugging the USB-C cable into a computer exposes the card as a flash drive, so you never pull it out to load music.

It's worth stealing for the small touches: a BOOT button that turns the screen off while the music keeps playing, and a resume feature that restarts the same song at the same position after power-off or a crash.

Resources · 4

Repository Hardware wiki Build wiki Web interface wiki

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