ComTek Atomic Clock — Windows

Important

v1.1.6 — BETA · Second public release (2026-05-03). Adds the Captain John's Marina (CaptJohn) theme (7th analog face) plus a hand-length pass that improves readability on every other analog face. Also: each Setup.exe wipes persisted settings at install (testing-clarity tradeoff during iteration; will be narrowed before the next public-distribution release). Bug reports: https://github.com/doxender/WindowsComTekAtomicClock/issues. The bundled Windows Service adjusts your system clock against NIST or NTP.br stratum-1 servers, so don't rely on this for timekeeping that matters in a regulated context until the patch cycle settles. Code-signing is still on the post-1.0 list — Windows SmartScreen will warn on first launch.

A Windows desktop atomic clock that synchronizes the system clock to NIST (Boulder, CO) or NTP.br (São Paulo, BR) stratum-1 servers, with 13 themable clock faces and a Chrome-style tabbed time-zone view.

Download v1.1.6

Asset	Size	Use
ComTekAtomicClock-v1.1.6-Setup.exe	97 MB	Recommended. Inno Setup installer — license screen, install-dir picker, Start Menu shortcut, Add/Remove Programs entry.
ComTekAtomicClock-v1.1.6-win-x64-self-contained.zip	135 MB	Portable — same payload, unzipped. For installs outside Program Files.

Both are self-contained (the .NET 8 runtime is bundled — no separate runtime install). All releases: https://github.com/doxender/WindowsComTekAtomicClock/releases.

Upgrading from v1.0.0

The installer auto-uninstalls a prior v1.0.0 install (matching AppId) and resets persisted settings to defaults. Your tabs and theme picks will reset; system-clock sync state lives in the Windows Service and isn't touched.

SmartScreen warning

The exes are not Authenticode-signed yet. Windows SmartScreen will warn ("Windows protected your PC" / "unknown publisher") on first launch. Click More info → Run anyway. Code-signing is the highest-priority post-1.0 item.

Features

• Stratum-1 atomic time sync — NIST Boulder pool (default, 10 named servers across Gaithersburg, MD + Fort Collins, CO, plus the time.nist.gov anycast) and NIC.br / NTP.br pool (5 GPS-disciplined servers in São Paulo, BR). Switch the source via Settings.
• 13 themable clock faces — 7 analog (Atomic Lab, Boulder Slate, Aero Glass, Cathode, Concourse, Daylight, Captain John's Marina — v1.1+) + 4 digital (Flip Clock, Marquee, Slab, Binary Digital) + 2 encoders (Binary, Hex). Atomic Lab is the default. Picker reachable from the ? overlay (in-tab) or ⋯ menu (floating window) → Themes….
• Captain John's Marina (CaptJohn) — v1.1+ — parchment + brass face with the Rio Dulce marina's "Busted Flush" logo at 40% opacity. The bottom-left ☠ Jolly Roger button opens a popup with three controls: Hora Chapín (lazy bar-clock mode — minute hand jitters ±3 min, syncs to real time on every :00 / :30; real hands at 10% opacity behind it); Almuerzo (12:00 demo — sets clock to 11:55 and plays the noon flash event over the next 10 minutes); Fini (5:00 PM demo — same shape, 16:55 → 17:05). The flash event also fires automatically at real noon and real 5 PM regardless of mode.
• Chrome-style tabbed time-zone view — native WPF TabControl; right-click a tab → Settings; + New tab / + New window toolbar buttons; per-tab IANA time zone (~140 zones).
• Free-floating clock windows — spawn via + New window or per-tab "Open in new window". Each hosts one clock; single ⋯ overlay button hosts Settings / Themes / Bring back into tabs / Help / About.
• Per-face source label — single warm-amber BOULDER or BRASIL header on every theme reflects the active time source at a glance.
• Background Windows Service that syncs the system clock via SNTP. Runs only while the UI is open (alpha simplification — start= demand). User-selectable cadence: 6 / 12 / 24 hours (default 12).
• Live last-sync display in the status bar (Last sync: 12s ago (corrected −8.7 ms)). Refreshed every second; IPC fetch every 5 s.
• Persistent state — per-user UI state (tabs / themes / time zones / windows) in %APPDATA%\ComTekAtomicClock\settings.json; per-machine sync config in %ProgramData%\ComTekAtomicClock\service.json. Atomic write, corrupt-file recovery, forward-compat via [JsonExtensionData].

Deferred to post-1.0

See TODO.md for the full ~38-item open list. Headline items:

• Timer + Countdown modes (active queue)
• Magnetic-snap floating windows (Phase 2)
• System tray icon + minimize-to-tray
• Five-slot color overrides (Ring / Face / Hands / Numbers / Digital)
• Time-format selector UI (Auto / 12h / 24h)
• Authenticode code-signing (kills the SmartScreen warning)
• MSIX packaging + GitHub Pages publish pipeline
• ARM64 build target

Architecture

Four-project .NET 8 solution. Buildable from CLI alone (dotnet build); Visual Studio 2022/2026 recommended for debugging + the XAML designer but not required.

Project	Type	Target	Runs as	Purpose
ComTekAtomicClock.UI	WPF App	net8.0-windows	Current user (asInvoker)	FluentWindow + Mica, tabbed UI, clock faces, dialogs, free-floating windows
ComTekAtomicClock.Service	Worker Service	net8.0-windows	LocalSystem	SNTP query to the active stratum-1 pool, calls SetSystemTime, schedules periodic sync, hosts the named-pipe IPC server
ComTekAtomicClock.Shared	Class Library	net8.0	n/a (referenced)	Settings models, TimeSource enum, IPC contracts, NTP packet types
ComTekAtomicClock.ServiceInstaller	Console (admin)	net8.0-windows	LocalSystem (one-shot via UAC)	sc.exe create / sdset / delete to register the Windows Service; sets %ProgramData% ACLs

UI ↔ Service IPC over a named pipe (ComTekAtomicClock.UiToService) using length-prefixed JSON envelopes. Schema-versioned, ACL-restricted to interactive users + LocalSystem. Contract in ComTekAtomicClock.Shared.Ipc.

The Service is the only component with rights to change the system clock; the ServiceInstaller is the only component requiring admin elevation, and only when the user clicks "Install / start the time-sync service" on the first-run banner.

For the full authoritative spec see SPEC.md (~1,650 lines, code-as-ground-truth).

Build from source

Prerequisites

• Windows 10 (1809+) or Windows 11
• .NET 8 SDK
• Git
• (Optional) Visual Studio 2026 or 2022 — Community is fine. Install the .NET desktop development workload.
• (Optional, for building the installer) Inno Setup — winget install JRSoftware.InnoSetup.

Build

From this directory (windows/):

# Restore + build all four projects
dotnet build -c Debug

# Run the UI in the foreground (during development)
dotnet run --project src/ComTekAtomicClock.UI

# Run the Service interactively in dev (does NOT require admin while
# running as a console app; only requires admin when registered with SCM)
dotnet run --project src/ComTekAtomicClock.Service

Production install of the Windows Service (development workflow)

The UI's first-run banner launches ComTekAtomicClock.ServiceInstaller via UAC. To install manually after a Release publish:

# After:  dotnet publish -c Release -r win-x64 --self-contained true
ComTekAtomicClock.ServiceInstaller.exe install --service-exe "<full path>\ComTekAtomicClock.Service.exe"

(The legacy sc.exe create … start= auto shape is wrong for this build — v1.0 uses start= demand with the UI managing the service lifecycle.)

Building the release package

See SPEC.md §20 for the full pipeline. The version comes from tools/installer.iss (MyAppVersion); update both the .csproj <Version> and the .iss MyAppVersion for a release. Short version, with $ver as the version string:

$ver = "1.1.6"   # match the csproj <Version> / installer.iss MyAppVersion

# 1. Self-contained publish of all three projects (~315 MB output)
dotnet publish src\ComTekAtomicClock.UI\ComTekAtomicClock.UI.csproj `
    -c Release -r win-x64 --self-contained true -o release\v$ver\UI
dotnet publish src\ComTekAtomicClock.Service\ComTekAtomicClock.Service.csproj `
    -c Release -r win-x64 --self-contained true -o release\v$ver\Service
dotnet publish src\ComTekAtomicClock.ServiceInstaller\ComTekAtomicClock.ServiceInstaller.csproj `
    -c Release -r win-x64 --self-contained true -o release\v$ver\Installer

# 2. Copy supporting docs into the staging dir
Copy-Item LICENSE,README.md,CHANGELOG.md,SPEC.md release\v$ver\

# 3. Compile the Inno Setup installer
& "$env:LOCALAPPDATA\Programs\Inno Setup 6\ISCC.exe" tools\installer.iss
# Output: release\ComTekAtomicClock-v$ver-Setup.exe (~97 MB)

Heads-up — the installer wipes user settings (v1.1.6+). Every Setup.exe resets %APPDATA%\ComTekAtomicClock\settings.json and %ProgramData%\ComTekAtomicClock\service.json at install time, so each install starts from the code's baked-in defaults. Intentional during the alpha/beta iteration cycle (testing clarity); will be narrowed before public-distribution releases. See CHANGELOG.md [1.1.6].

NIST + NTP.br usage notes

• Boulder source — anycast time.nist.gov (load-balances across the whole NIST pool); 10 named stratum-1 servers across Gaithersburg, MD (time-{a..e}-g.nist.gov) and Fort Collins, CO (time-{a..e}-wwv.nist.gov). NIST asks for ≤ 1 query / 4 s per server.
• Brazil source — a.ntp.br anycast + b/c/d/gps.ntp.br named servers. NIC.br asks for ≤ 1 query / 1 s per server.
• The service's per-server poll-interval floor is 4 s, satisfying both. Default sync cadence is 12 hours, well within both operators' guidance.
• All servers are publicly available; no API key required. NIST list: https://tf.nist.gov/tf-cgi/servers.cgi. NTP.br: https://ntp.br/guia-mais-rapida.php.

Repository layout

ComTekAtomicClock/
└── windows/                              <-- this repo
    ├── ComTekAtomicClock.slnx            (.NET 9+ XML solution format)
    ├── README.md                         (you are here)
    ├── SPEC.md                           (authoritative spec — code-as-ground-truth)
    ├── CHANGELOG.md                      (per-version problem/solution log)
    ├── CONTEXT.md                        (running decisions / constraints / gotchas)
    ├── TODO.md                           (consolidated open backlog)
    ├── requirements.txt                  (legacy spec — kept for history; superseded by SPEC.md)
    ├── LICENSE                           (MIT)
    ├── design/                           (visual design artifacts: 12 .svg theme previews + a CaptJohn .png mockup + index.html gallery + Cinzel-Variable.ttf for the CaptJohn numerals)
    ├── docs/
    │   └── code-vs-spec-audit.md         (drift audit between requirements.txt and code)
    ├── tools/
    │   ├── build-icon.ps1                (regenerate Assets/AppIcon.ico from PNG master)
    │   └── installer.iss                 (Inno Setup script for the Setup.exe)
    └── src/                              (C# source)
        ├── ComTekAtomicClock.UI/         (WPF app)
        ├── ComTekAtomicClock.Service/    (Worker Service)
        ├── ComTekAtomicClock.Shared/     (class library)
        └── ComTekAtomicClock.ServiceInstaller/   (privileged helper)

The parent ComTekAtomicClock/ folder is reserved as an umbrella for future per-platform repos (e.g. mac/, linux/).

Repository remote

origin  https://github.com/doxender/WindowsComTekAtomicClock.git

Reporting issues

https://github.com/doxender/WindowsComTekAtomicClock/issues — please include:

• Version (visible upper-left on every clock face: e.g. v1.1.6)
• Windows version (winver)
• Steps to reproduce
• Expected vs. actual behavior
• Any output from %ProgramData%\ComTekAtomicClock\ log if a sync issue, or the clock-face screenshot if a UI issue

License

MIT © 2026 Daniel V. Oxender.