Chapter 04

Display and idle clock

The panel always shows one primary scene. When nothing else owns the display, B0RD OS presents an idle clock — a clear face for wall time, with soft motion behind the hands so the sign still feels alive without shouting for attention.

Fig. 3 — Base modes (1 clock / 2 countdown) and temporary notify overlay (3). Shapes + numbers, not hue alone.

Fig. — Idle clock panel scene (diagram; desk-context photo H2 pending — MEDIA_SHOT_LIST.md)

Base preference

Every sign has a base preference: idle clock orlaunch countdown. That preference is what returns when a temporary overlay ends. Fresh devices may arrive in countdown until you choose otherwise; either choice is valid for day-to-day use.

Change the base preference from the on-device interface or from the USB control plane. The change takes effect immediately; you do not need to reboot.

Idle clock behavior

The idle clock expects a trustworthy wall time. When network time has been established (or time has been set from the control plane), hands and readouts follow your timezone offset (net.time.tz_offset_min, minutes east of UTC) and optional label. Until time is known, the face may still appear, but countdown-style “time remaining” strings elsewhere on the product will not be meaningful yet.

The underlay motion is decorative. It is meant to keep the panel from looking frozen — not to compete with the time. If a notification is active, the system temporarily replaces that underlay with a higher-contrast pattern so the alert band stays readable.

Brightness and layers

Master brightness (display.brightness, 0–255) is the overall ceiling. Each compositor layer is a percent of that ceiling: underlay (FX) → base (clock / countdown) → notify. Defaults: underlay 12, base 80, notify 100.

Key	Role	Default
`display.brightness`	Overall intensity ceiling	255
`display.layer.underlay`	Background motion (0–100%)	12
`display.layer.base`	Clock / countdown chrome (0–100%)	80
`display.layer.notify`	Notification overlay (0–100%)	100

Full ranges: Settings reference. Raise overall brightness for sunlit rooms; lower it for nightstands and close desk use.

Accessibility presets

A global accessibility preset (a11y.preset) can favor structure and luminance over subtle color: standard,high contrast, or colorblind safe. High-contrast modes strengthen separators and underlay motion so the panel remains readable when hue alone is unreliable. An optional reduce-motion flag freezes decorative animation. See also Features.

What can interrupt the clock

Launch countdown — when selected as the base mode, the board replaces the clock with mission cards (and may share time back with the clock via playlist timing).
Notifications — short overlays that restore the previous scene when they clear or expire.