DomesdayDuplicator

Domesday Duplicator (DdD)

The Domesday Duplicator is a LaserDisc capture focused, USB 3.0 based DAQ capable of 40 million samples per second acquisition of analogue RF data at 10-bits resolution.

Please see the Project Documentation for details of the project and for access to the project documentation. For contributing guidelines, see CONTRIBUTING.md.

The capture application

Capture is via an easy to use GUI capture application, with real-time signal analysis — waveform, spectrum analyser and spectrogram, amplitude history and live capture statistics — so you can see the RF while it is being sampled rather than after the fact.

The application also drives a Pioneer LaserDisc player over serial, runs whole-disc automatic captures, and updates the Duplicator's own firmware and gateware over USB. The Capture Application documentation covers every panel.

Installing — no compilation required

There is absolutely no need to compile anything. All end-user installs must be performed using the provided binary packages and firmware images. Building from source is a development activity only, and nothing you need as a user requires it.

The capture application

Download from the releases page and follow the installation page for your platform:

Every release also carries SHA256SUMS and a PROVENANCE.txt recording the commit each asset was built from. Verify your download against SHA256SUMS.

Firmware and gateware

You do not build these either. Firmware releases publish a single signed update bundle, domesday-duplicator-update-<version>.dddfw, and the capture application installs it for you: Tools → Firmware → Update firmware…. The application verifies the bundle's signature and every payload digest before it writes anything, and reports the version it reads back off the live device afterwards. See Updating your Domesday Duplicator.

A board that has never been programmed is handled the same way, with no jumper and no shell — see Bringing up a new or legacy board. Firmware releases also publish the raw images (firmware.img, the provisioning .jic and the factory .svf) for bench recovery, but the bundle is the supported route.

Every released artefact is built by CI from the tagged commit; nothing is built on a maintainer's machine or attached by hand (release pipeline).

Cloning the repository

Everything is in this one repository. There are no git submodules, so a plain clone gives you the complete project:

git clone https://github.com/Domesday86/DomesdayDuplicator.git

Repository layout

Developing the project

Do NOT install from source unless you intend to develop the software — see Installing above for user installations.

Nix on Linux is the only supported environment

The only supported development and build environment is Nix on Linux. There is exactly one flake.nix, at the repository root, and exactly one flake.lock; every toolchain the project needs is pinned by it, and CI builds through the same flake, so a build that fails under Nix is a real failure rather than an environment quirk.

Pull requests that introduce another development or build environment will not be accepted. That includes alternative build systems, per-distribution dependency lists, and packaging intended to make a component build without Nix. If you develop on macOS or Windows, use a Linux virtual machine — that is the supported route, and it is the only one.

Building

Run any of these from anywhere in the working tree; Nix walks up to find the flake at the root, so .#ddd-gui resolves identically from ddd-gui/ and from the repository root.

nix develop                          # every component's tools in one shell
nix flake check                      # build everything and run the whole T1–T4 test suite

The capture application installs three binaries: ddd-gui, plus ddd-update and ddd-jtag, which drive the same engine from a shell.

Components deliberately carry no flake of their own: an earlier layout gave each one a thin flake for the cd ddd-gui && nix develop shorthand, and every one of those resolved nixos-unstable into a lock file of its own — so entering the tree through a component quietly got a different nixpkgs from the root pin. The reasoning is in the header comment of flake.nix.

Two caveats on the FPGA row. Quartus Prime Lite is unfree, x86_64-linux only and cannot be served from a binary cache, so nix build .#bitstream means a multi-gigabyte first download and is excluded from nix flake check — the per-commit tier must never require an unfree download of anyone. It is built by CI, in a workflow of its own that runs on gateware changes and from release tags, so every released bitstream is CI-built from the tagged commit. nix develop .#fpga — without -quartus — gives the free tools instead: Verilog lint, simulation and a language server, with no Quartus at all, and that covers most gateware work.

Build directories are build/ under each component and are gitignored. Never build in-tree: in the gateware's project directories in particular, Quartus rewrites the tracked .qsf on every compile.

On NixOS, device permissions come from the flake's module — set hardware.domesdayDuplicator.enable = true;, which covers the Duplicator, the FX3 and the on-board USB-Blaster together. Elsewhere, see Linux device access.

AGENTS.md records the project conventions and TESTING.md the test tiers, including the hardware-in-the-loop capture-integrity procedure that is the most important test in the project.

The Decode Family

The samples the DdD captures can be used with the whole family of decoders that make the FM RF archival workflow ready to use today.

The original design was for the wide bandwidth of LaserDisc RF — making it suitable for all of the more bandwidth restricted mediums too (that have a single stream of RF).

Please see the documentation for more details

3D Printed Case

The Domesday Duplicator also has 3D models and ready to use STL files for producing 3D printed cases, to protect from dust or line with copper tape for affordable EMI shielding for example.

Authors

Domesday Duplicator is designed and maintained by Simon Inns.

Licences

• Software Licence — GPLv3
• Hardware Licence — Creative Commons BY-SA 4.0 (full text in hardware/pcb/LICENSE.txt)