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Version: 6.x

Data Streams

Data Streams is a Grafana-style, fully customizable telemetry dashboard inside UAVcast-Pro. Build multiple named boards, drag and resize widgets, configure each one to bind any MAVLink scalar or injected NAMED_VALUE_FLOAT signal, and watch the values stream live. History persists across page refresh.

Find the page in the sidebar under Data Streams.

What you can visualize​

Anything that flows through MAVLink is a candidate:

  • Standard flight controller telemetry — altitude, battery voltage, airspeed, GPS fix, attitude, link quality, anything published by ArduPilot / PX4.
  • Injected named values — signals you push into the stream with the Injectors feature (radiation, LTE signal, custom sensors).
  • Anything else a connected component emits as NAMED_VALUE_FLOAT / NAMED_VALUE_INT — a Lua script on the autopilot, a payload computer, a third-party radio that publishes its own diagnostics.

Concepts​

Dashboards​

A dashboard is a named board with its own widget layout. You can have as many as you want; the page remembers which one you had open last.

Admins can:

  • Create a new dashboard from the tab switcher
  • Rename, duplicate, delete, import, and export existing dashboards from the kebab menu
  • Toggle Edit mode to drag, resize, configure, and remove widgets
  • Toggle Fullscreen for clean operator view

Non-admin users see dashboards read-only. They can still switch between boards and toggle fullscreen.

Widgets​

Each widget binds to one or more signals and renders them in a particular way. Widget types:

TypeBest for
NumericBig single-value readouts (battery voltage, altitude).
SparklineNumeric + tiny inline trend, no axes.
Line chartFull chart with axes, legend, grid, multiple series.
GaugeRadial dial with threshold arcs (signal strength, fuel level).
BarHorizontal indicator bar with threshold zones.
StatusText widget showing last value + "X seconds ago". Good for slow signals.
Named-value tableLists every active NAMED_VALUE_* signal currently in the stream. Used as a discovery view.

Signal keys​

A signal is identified by a key like mavlink:battery.voltage or RAD1@1:194. The format is name@sysid:compid for injected named values, or mavlink:<path> for standard MAVLink scalars. The widget config dialog provides a searchable list of active keys, but you can also type a key by hand to pre-create a widget for a signal that has not arrived yet.

Creating a dashboard​

  1. Open Data Streams.
  2. If you are an admin and there are no dashboards yet, click Create your first dashboard and give it a name.
  3. To create additional dashboards later, use the + button next to the dashboard tabs, or open the kebab menu and choose New dashboard.

Adding widgets​

  1. Toggle Edit mode on (admin only).
  2. Click Add widget and pick a type.
  3. The new widget is placed in the next free grid slot and opens its config dialog.

Configuring a widget​

The widget config dialog has four tabs:

  • Source — pick one signal (or multiple for line charts). The selector lists every active key from the live stream. Type a key by hand to pre-create a widget for a signal not yet seen.
  • Display — title, color, units, prefix / suffix, decimal places.
  • Range — min, max, auto-fit toggle, plus a list of thresholds (each with a value, color, optional label). Thresholds drive numeric tile colors, gauge arcs, and bar zones.
  • Chart (sparkline / line only) — window seconds (60 / 300 / 900 / 3600 / custom), legend, grid, line width, area fill.

Changes apply immediately. The layout is auto-saved (debounced 800 ms) so you can keep dragging without thinking about a Save button.

Layout​

In Edit mode, every widget can be:

  • Dragged by its title bar.
  • Resized from the bottom-right corner.
  • Configured or Removed from the kebab on the widget header.

Out of edit mode, widgets stay frozen in place. This is the operator-facing layout.

Empty-state hints​

If a widget shows "No samples yet for RAD1@1:194" it means the signal name and sysid:compid combo has not been seen on the stream since the page loaded. Either:

  • The sensor or injector is not running.
  • The name on the injector has a prefix that you have not accounted for.
  • The sysid / compid does not match the source.

The named-value table widget is the easiest way to discover what is actually flowing.

Import / Export​

Each dashboard can be exported as JSON (kebab menu → Export) and imported on another instance (kebab menu → Import). The JSON round-trips through a schema validator, so a malformed import is rejected with a clear error.

This is how you share a known-good operator layout across multiple aircraft, or version-control your dashboards.

Persistence​

Dashboards and their widgets are stored in the local SQLite database (telemetry_dashboard table). They survive UAVcast restarts. Sample history is in-memory only and resets when the page reloads, but the values keep flowing live as long as the source is publishing.

Performance notes​

  • The page keeps ~3600 samples per signal in memory. At 10 Hz that is 6 minutes; at 1 Hz it is an hour.
  • Line charts use a windowed slice of that buffer, so longer windows are not free, but the default 5-minute window is cheap.
  • Many widgets on one dashboard is fine. Many high-rate signals on one widget is what slows things down. If a chart drops frames, lower the publish rate at the source or raise the Rate limit on the injector.