Echo: Open Hardware Music Player

Echo is an open hardware platform for music players. The goal of the project is to produce a high quality music player, based on and designed with free software. It's primarily designed to run Rockbox, a free music player firmware with support for many codecs, and a wide array of features.

The PCB is designed with KiCAD 9.0, and there is an unfinished 3D-printable case designed with build123d.

All designs are available under the CERN-OHL-S v2 license.

The current version of the Echo player is called the Echo R1. In the future, there could be new player models if there are significant changes to the features or form factor, but old models will always be supported.

Echo R1

• Size: 60x100x15mm (approx)
• Weight: TBD

The R1 has a 4-way D-pad and 6 multi-function buttons on the faceplate, which can be used to quickly navigate your music library and control playback. There are dedicated volume and power buttons (not pictured), and a sliding hold switch near the power button, which locks the buttons against accidental presses when the player is in your pocket or bag.

There are two 3.5mm jacks, one for headphones, and one true line-out port. The headphone jack supports recording from an in-line microphone and playback control by an in-line remote. Both jacks can be used simultaneously.

The removable memory card slot allows up to 2 TiB of storage for your music and files. The USB-C port is used for charging and file transfer, and supports high-speed USB 2.0.

The battery socket accepts the widely available BL-5C battery, and the battery can easily be replaced without special tools when it starts to wear out.

Hardware specifications

Component	Description
CPU	STM32H743 @ 480 MHz
Memory	32 MiB SDRAM @ 120 MHz
Audio	TLV320AIC3104, up to 96 KHz, 0.707 V RMS
Display	18-bit, 320x240, 2.3 inch LCD
Storage	Expandable external memory card slot
USB	USB 2.0 @ 480 Mbps (High-speed)
Headphone out	Yes (3.5mm jack)
Line out	Yes (3.5mm jack)
Microphone	Can use wired headphone mic
RTC	Yes, with wake-up alarm function
Battery	Replaceable BL-5C battery (~1000 mAH)

Status

There are two versions of the R1 in the repo, the Rev1 and Rev2.

Rev1 is complete from an electrical standpoint but has a poorly thought out mechanical design. A very early Rockbox port exists but it is far from usable.

Rev2 is unfinished and focused mostly on solving the mechanical issues with Rev1 properly. It is a near total redesign from an electrical perspective, and uses a STM32H7R3 series CPU which was selected mainly to simplify routing.

Known issues (R1-Rev1 only)

• Reference designators in the schematics don't make much sense, there are gaps in the numbering and samed-valued components are not in contiguous ranges.
• Mounting screws are placed haphazardly and only two of them proved to be usable.
• The placement of the LCD and LCD connector is very awkward and makes it hard to diassemble the machine non-destructively.
• The lack of mounting holes also makes it difficult to connect front and back halves of the case securely.

License

Unless otherwise noted, all files in this repository, including this README, are available under the terms of the CERN-OHL-S version 2 license, which should be found in the file COPYING.txt alongside this README; or at https://ohwr.org/cern_ohl_s_v2.txt.

Credits

Copyright (C) 2024-2025 Aidan MacDonald