wxdash

Real-time weather dashboard for Raspberry Pi kiosk display.

Displays live conditions from a Davis Instruments WeatherLink Live over HTTP and UDP, with optional air quality data from a PurpleAir sensor. Designed to run fullscreen, unattended, and always-on.

Features

• Real-time data from WeatherLink Live (HTTP polling + UDP broadcast)
• Arc gauges for temperature, humidity, pressure, wind speed, UV index, solar radiation, rain rate, dew point, and feels-like
• Wind rose histogram showing directional frequency over a rolling window
• AQI multi-ring gauge from a local PurpleAir sensor
• Sparkline trend graphs for all sensors
• Full-screen kiosk mode (--kiosk flag)
• Responsive layout (720p to 4K)

Requirements

• Qt 6 (Core, Network, Quick, Qml, Svg, Test)
• CMake 3.22 or later
• Ninja (recommended)
• C++17 compiler
• Davis Instruments WeatherLink Live reachable on local network
• PurpleAir sensor on local network (optional, for AQI gauge)

Building

Standard desktop build:

cmake -B build -G Ninja -DCMAKE_BUILD_TYPE=Release
cmake --build build
./build/src/wxdash           # windowed mode
./build/src/wxdash --kiosk   # fullscreen mode

Raspberry Pi Deployment

This section documents how to deploy wxdash as a kiosk on a Raspberry Pi 4 or 5.

Prerequisites

• Raspberry Pi 4 or 5 running Pi OS Bookworm (64-bit recommended)
• Qt 6 development packages:

sudo apt install qt6-base-dev qt6-declarative-dev qt6-svg-dev qt6-shadertools-dev \
    libqt6quick6 libqt6qml6 libxkbcommon-dev cmake ninja-build

• Mesa V3D driver — this is the default on Pi OS Bookworm; no additional configuration is needed.
• GPU memory: the default 76 MB is sufficient for Mesa. Increase to 128 MB only if you see rendering issues by adding gpu_mem=128 to /boot/firmware/config.txt and rebooting.

Build and Install

Clone and build on the Pi (or cross-compile and copy):

git clone <repo-url> wxdash
cd wxdash
cmake -B build -G Ninja -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=/usr/local
cmake --build build

Pi Zero 2 W note: The Pi Zero 2 W only has 512 MB of RAM, which is not enough to compile Qt 6 C++ without swap. Add a swap file and limit build parallelism:

sudo fallocate -l 1G /swapfile
sudo chmod 600 /swapfile
sudo mkswap /swapfile
sudo swapon /swapfile
cmake --build build -j1

To make the swap permanent, add this line to /etc/fstab:

/swapfile none swap sw 0 0

The build will be slow (~30-60 min) but should complete without the OOM killer rebooting the Pi.

Install the kiosk component (binary, QML module, systemd service, EGLFS config, desktop entry, icon):

sudo cmake --install build --component kiosk

Alternatively, use the convenience target that also enables the systemd service:

sudo cmake --build build --target install-kiosk

User Permissions

The systemd service runs as the user who configured the build (the value of SERVICE_USER, which defaults to $USER at cmake configure time). That user must be in the render, video, and input groups for DRM and input device access:

sudo usermod -aG render,video,input $USER

Log out and back in (or reboot) for the group changes to take effect.

To override the service user explicitly, pass -DSERVICE_USER=<username> when running CMake:

cmake -B build -G Ninja -DCMAKE_BUILD_TYPE=Release \
    -DCMAKE_INSTALL_PREFIX=/usr/local \
    -DSERVICE_USER=myuser

EGLFS Configuration

The installed EGLFS config at /usr/local/share/wxdash/eglfs.json targets /dev/dri/card1, which is correct for Pi 4 and Pi 5 with the Mesa V3D driver.

If the display is blank after starting the service:

1. List DRM device nodes: ls /dev/dri/
2. On some Pi OS versions the render node may be card0 instead of card1.
3. Confirm the V3D node: sudo drminfo /dev/dri/card1 should report the V3D driver.
4. If needed, edit /usr/local/share/wxdash/eglfs.json and change the device field to the correct node, then restart the service.

systemd Service

# Reload unit files after install (if not using install-kiosk target)
sudo systemctl daemon-reload

# Enable auto-start at boot and start now
sudo systemctl enable wxdash.service
sudo systemctl start wxdash.service

# Check current status
systemctl status wxdash.service

# Follow live logs
journalctl -u wxdash.service -f

# Stop and disable
sudo systemctl stop wxdash.service
sudo systemctl disable wxdash.service

The service is configured with Restart=always so wxdash will restart automatically after a crash.

Network and Hostname Resolution

The application connects to weatherlinklive.local.cisien.com — this is a DNS name, not a plain mDNS .local address.

Verify resolution on the Pi:

nslookup weatherlinklive.local.cisien.com

If the name does not resolve, add a static entry to /etc/hosts:

<IP_ADDRESS> weatherlinklive.local.cisien.com

The PurpleAir sensor is accessed at http://10.1.255.41/json. Verify the Pi can reach that address:

curl -s http://10.1.255.41/json | head -c 200

Troubleshooting

Symptom	Likely cause	Fix
Black screen at boot	Wrong DRM device node in eglfs.json	Check journalctl -u wxdash -b for EGLFS errors; update device in eglfs.json
Permission denied on /dev/dri	User not in render/video groups	Run groups $USER; add missing groups with usermod -aG
QML module not found	QML_IMPORT_PATH not set or wrong path	Verify QML_IMPORT_PATH in service matches install prefix; check ls /usr/local/qml/wxdash/
No weather data	Hostname resolution or network failure	Run nslookup weatherlinklive.local.cisien.com and curl http://10.1.255.41/json from the Pi
High CPU / thermal throttle	Debug build in use	Rebuild with -DCMAKE_BUILD_TYPE=Release

License

MIT License — see LICENSE file for details.