---
title: Harmony
kind: side-project
role: Solo build
years: 2025 – present
status: in-progress
summary: >-
  An offline iPod-style MP3 player built on ESP32 + MicroPython.
  Hardware-agnostic Python core with a PC simulator for testing.
tags:
  - embedded
  - esp32
  - micropython
  - hardware
  - hobby
order: 5
---

There are no good simple MP3 players you can buy anymore. The iPod is
discontinued, the modern alternatives are either iOS apps or weird overpriced
audiophile bricks, and nothing is just a small thing with a wheel and a
screen that plays the music on the SD card.

So I'm building one. ESP32 microcontroller, MicroPython, a screen, a rotary
encoder, an SD card slot, headphone out. The Python core is hardware-agnostic
and runs in a PC simulator for testing — the physical device is just one of
the targets. Mark 2 is the current attempt; Mark 1 taught me what I needed
to know to start over.

It is the most fun I have had with a computer in years.