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HDMI Kiosk Mode

Plug a monitor and a gamepad into the ground station SBC. The agent launches Chromium in kiosk mode, rendering the Mission Control HUD route at full screen. You get video, telemetry overlays, and stick control without a laptop, phone, or internet connection.
Ground station HDMI output showing fullscreen video with HUD overlay

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What you need

  • Micro-HDMI to HDMI cable (Pi 4B uses micro-HDMI)
  • Any HDMI monitor or display (7” field monitors work well)
  • USB or Bluetooth gamepad (Logitech F310, Xbox, PS4, PS5, 8BitDo)
The ground station must have Mission Control installed locally. The install script handles this.

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How it works

When the ground station detects a display output at /dev/dri/card0, it starts three services:
  1. ados-mc-local serves a pre-built Mission Control at http://localhost:4000
  2. ados-kiosk launches Chromium inside the cage Wayland compositor, pointing at http://localhost:4000/hud
  3. Chromium renders the HUD route in fullscreen kiosk mode, with no address bar, no tabs, no browser chrome
The entire display chain runs locally on the SBC. No network traffic, no external server. Video from WFB-ng flows through MediaMTX on localhost. Telemetry comes from the local MAVLink WebSocket.

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The HUD layout

The /hud route is a stripped-down flight view designed for fullscreen use:
  • Full-frame video background (WebRTC from the local MediaMTX)
  • Top bar: link RSSI, flight mode, battery percentage, altitude, speed, GPS satellite count
  • Bottom bar: crosshair, artificial horizon, heading tape
  • Corner alerts: failsafe indicators, home distance, connection health
  • No menus, no maps, no multi-drone fleet views
This is the pilot-in-command view. For mission planning, configuration, and fleet management, use a laptop connected over WiFi or USB.

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Performance on Pi 4B

ScenarioCPU usageRAM usage
HUD idle (no video)12%280 MB
WebRTC 720p at 30 fps38%440 MB
WebRTC 1080p at 30 fps62%520 MB
WebRTC 1080p at 60 fps88%620 MB
For the Pi 4B, 720p at 30 fps is the sweet spot for kiosk mode. It leaves enough CPU headroom for the WFB-ng receiver, MediaMTX, and the agent services. Use 1080p only if you have a 4 GB Pi.

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Gamepad input

The Web Gamepad API in Chromium handles controller mapping. USB gamepads work immediately. Bluetooth gamepads need to be paired first. To pair a Bluetooth gamepad:
  1. Put the controller in pairing mode
  2. Use the OLED menu: navigate to Network > Bluetooth > Scan
  3. Select the controller from the list
  4. Press B3 (Select) to confirm
Or pair through the setup webapp Display page from your phone. Once paired, the gamepad sends stick inputs at 50 Hz through the existing MANUAL_CONTROL MAVLink message path. The same code that handles gamepad input in the browser on your laptop handles it here.

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Pilot-in-command (PIC)

When the kiosk starts and a gamepad is connected, the kiosk automatically claims PIC. If a laptop or phone also connects, they are observers until PIC is explicitly transferred. PIC transfer is done through:
  • The Mission Control Hardware tab on a connected laptop (click “Take Control”)
  • The OLED menu (B3 long-press to release PIC)
If the kiosk client disconnects (monitor unplugged, gamepad dies), PIC auto-transfers to the next connected client with an active gamepad. If no client has a gamepad, the agent sends failsafe intent to the flight controller (hover or RTL, depending on FC configuration).

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Display settings

You can configure HDMI output from three places:
  • OLED menu: Display > HDMI Resolution
  • Setup webapp: Display page
  • Mission Control Hardware tab: Physical UI sub-view
Available settings:
  • Resolution (auto-detect, 720p, 1080p)
  • Refresh rate (30 Hz, 60 Hz)
  • OLED brightness and auto-dim

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Booting into kiosk

The kiosk service uses cage as a minimal Wayland compositor. cage is designed for single-application kiosk use. It starts only when:
  1. A display output is detected (/dev/dri/card0 exists)
  2. The ground-station profile is active
  3. The local Mission Control build is available
If any of these conditions are not met, the kiosk service does not start. The OLED and WiFi AP still work normally.

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Graceful degradation

EventBehavior
Monitor unplugged mid-flightKiosk keeps running on virtual framebuffer. On re-plug, display returns in ~2 seconds
Gamepad disconnectedPIC transfers to next client, or failsafe triggers
Mission Control build missingChromium shows blank page, OLED shows error, agent runs normally
No display output at bootKiosk service skips, no errors

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