Front panel: OLED, buttons and touch display

A ground station can carry three optional front-panel parts. Each one works on its own, and the node runs normally without any of them.

Part	What it does	Service
I2C OLED (128x64 or 128x32)	A four-line status frame. View only.	`ados-oled-i2c`
Four buttons	Navigate the touch LCD.	`ados-pic` (the PIC arbiter reads and decodes the presses and passes them to the LCD renderer)
SPI touch LCD (480x320)	The full on-device interface: dashboard, detail pages, settings, mesh role, pairing.	`ados-oled` (runs the native `ados-display` renderer)

The OLED and the LCD (or an HDMI monitor) can be fitted at the same time.

Ground station LCD dashboard at 480x320 with four tiles, a top bar with hostname and role, and a five-icon tab bar — The LCD dashboard: Radio link, Drone, Mesh and Uplink / Cloud tiles, with the tab bar at the bottom.

OLED status display

The I2C OLED shows one status frame, refreshed every 2 seconds from the agent’s ground-station status:

The hostname.
The LAN IP address.
The link: link: idle before a drone is heard, then link <state> <rssi>dBm.
The status: PAIRING <n>s while a mesh accept window is open, otherwise role: <role>, then uplink up or ready.

I2C OLED showing four lines: hostname, LAN IP, link connected with RSSI in dBm, and role direct — The I2C OLED status frame on a direct-role ground station with a linked drone.

The OLED has no menu and does not read the buttons.

Wiring and detection

Wire SDA, SCL, VCC (3.3 V) and GND to the board’s I2C bus 1. On a Raspberry Pi the installer enables I2C; reboot once after the install so the bus appears. The service starts only when /dev/i2c-1 exists, then probes address 0x3C and then 0x3D. With no panel answering, it exits cleanly.

Settings

Set these in /etc/ados/env and run sudo systemctl restart ados-oled-i2c:

Variable	Effect
`ADOS_OLED_ADDR`	Use exactly this I2C address (for example `0x3D`) instead of probing.
`ADOS_OLED_BUS`	I2C bus number. Default `1`.
`ADOS_OLED_CONTROLLER`	`sh1106` for an SH1106 panel. Default SSD1306.
`ADOS_OLED_HEIGHT`	`32` for a 128x32 panel. Default 64.

Brightness is ground_station.ui.oled.brightness (0 to 255, default 204), applied as the panel contrast whenever it changes. Set it with PUT /api/v1/ground-station/ui/oled.

Buttons

Four momentary buttons drive the touch LCD. A press is short or long: a long press is held at least 2 seconds and fires on release; holding 6 seconds or more cancels the press.

Button	BCM GPIO	Header pin	Short press	Long press
B1	GPIO 5	Pin 29	Next tab	Toggle backlight
B2	GPIO 6	Pin 31	Uplink detail	Pair drone page (with QR)
B3	GPIO 13	Pin 33	Confirm	Pair drone page
B4	GPIO 19	Pin 35	Back	More menu

These are the fallback pins. A board profile can declare its own pins in a buttons block (up, down, select, back), which the installer writes into the board record at /run/ados/board.json; the four pins map in that order to B1 to B4. The Raspberry Pi 3 and 4B profiles use the pins above.

Remap the buttons

Remaps are stored in ground_station.ui.buttons.mapping and written from Mission Control (node panel, Buttons) or with PUT /api/v1/ground-station/ui/buttons. The keys are B1_short, B1_long through B4_long. The panel acts on these eight actions:

Action	What it does
`cycle_screen`	Next tab
`back`	Close a detail page, or return to the dashboard
`menu`	Open the More menu (or Settings)
`confirm`	Confirm the focused control
`toggle_backlight`	Toggle the LCD backlight
`show_network`	Open the Uplink detail page
`show_qr`	Open the Pair drone page
`pair_drone`	Open the Pair drone page

Any other action name does nothing.

Touch display (SPI LCD)

The LCD is drawn by the native ados-display renderer under the ados-oled unit.

Auto-provisioning

Detect

The board’s hardware profile lists its supported displays. With --display auto (the ground-station default) the installer picks the panel the board declares; --display <id> selects one explicitly and --display none opts out.

Provision

The installer enables the display overlay and the kernel modules, and records the framebuffer, rotation and panel in /etc/ados/display.conf.

Bind

After the reboot the renderer finds the framebuffer and the touch input attaches. If the panel never binds, the installer’s probe restores the previous boot configuration. If the touch controller is missing when the renderer starts, or drops out later, the renderer keeps looking for it every 500 ms, so a late-loading driver or a re-seated panel gets touch back without a restart.

Pages

A bottom tab bar holds five tabs: Dashboard, Video, Settings, Link stats and Channel hops. The top bar shows the hostname, the role, CPU, RAM and temperature, and the clock. The dashboard has four tiles. Tap one to open its detail page:

Radio link: signal, rate and FEC counters. Shows Hardware while no radio adapter is found.
Drone: the paired drone. Shows Pair drone while no drone has been heard.
Mesh: role, peers and gateway. Shows Setup wizard while setup is not finished or the role is unset, and MESH N/A on a direct node that cannot join a mesh.
Uplink / Cloud: the active uplink and cloud reachability.

Other detail pages: Pair drone (paired drone, key fingerprint, two-tap Unpair), Access point (name, passphrase and join QR code), Diagnostics, About and Calibration. The More menu holds the overflow entries, and an installed extension can add its own page.

Ground station LCD Link stats tab with signal, bitrate and FEC counters — The Link stats tab: radio signal with its RSSI trend, bitrate, packet and FEC counters, and the decoder and system bands.

Mesh detail page

Tap the Mesh tile to open the mesh detail page. It shows the active role, then one of three bodies: a notice on a direct node, a “mesh down” notice while the mesh forms, or the list of peers. The footer shows the selected gateway and a partition badge.

To change the role, tap Switch role. A picker opens with DIRECT, RELAY and RECEIVER. A role change re-forms the link, so it takes two taps: the first arms the choice (“Tap again: RELAY”), the second writes it through PUT /api/v1/ground-station/role. Mesh pairing itself runs from Mission Control or REST; see Build a mesh.

Ground station LCD Mesh page with the role picker open and the relay row reading Tap again: RELAY — The role picker with RELAY armed, waiting for the confirming tap.

Touch gestures

Gesture	Threshold	Use
Tap	Under 400 ms, under 12 px of movement	Open a tile or press a control
Long press	400 ms or more, under 12 px	Press-and-hold controls
Swipe	Under 250 ms, 24 px or more	Move between pages
Drag	Any other motion	Scroll a list

Calibration

Touch calibration is a nine-point (3x3) capture. It runs from the setup wizard’s Local display step, from Mission Control (node panel, Display), or from the Calibration page on the panel. Results persist across reboots.

Supported boards

Board	Panel	Controller	Touch	Resolution
Raspberry Pi 4B	Waveshare 3.5” RPi LCD (A)	ILI9486	ADS7846	480x320
Raspberry Pi 3	Waveshare 3.5” RPi LCD (A)	ILI9486	ADS7846	480x320
Radxa Cubie A7Z	Waveshare 3.5” RPi LCD (A)	ILI9486	ADS7846	480x320
Radxa ROCK 5C Lite	Waveshare 3.5” RPi LCD (A)	ILI9486	ADS7846	480x320

The Raspberry Pi 4B and the ROCK 5C Lite also support an alternative wiring: an 800x480 HDMI panel with an XPT2046 resistive touch layer on SPI. A rig uses one wiring or the other. The touch layer is calibrated with the same nine-point capture. A new board adds a displays block to its hardware profile; see HAL and tiers.

Mission Control mirror

The Display tab of the ground station’s node panel in Mission Control mirrors the panel: type, controller, resolution, rotation, last-touch age, the current page and the calibration state, with a live page preview. You can switch pages and start calibration from there. The Buttons tab holds the button mapping and Bluetooth gamepad pairing. See Ground station node panel.

Graceful degradation

Every part of the front panel is optional. With no OLED, its service exits cleanly. With no LCD, the renderer does not start. The dashboard, the cockpit and Mission Control still expose every setting.

Get started

Connect your devices

At the ground station

Mesh and distributed receive

Network and fleet

Diagnose

Front panel: OLED, buttons and touch display