Help
Most problems are one of these.
Stars, but no planes
Almost always the location: it's still looking at San Francisco. On the phone page, set Location. Then read the line at the top of the phone page: it says what it's doing and why, if something's wrong. Far from an airport? Calibration → Radius, make it bigger.
The projector says “no signal”
Use the HDMI socket right next to the power socket, push the plug in firmly, and turn the projector on before the Pi.
My phone can't open skylight.local
Make sure the phone is on your home Wi-Fi, not mobile data or a guest network. Some Android phones can't find that name: on the Pi, open the Terminal, type hostname -I, and use the number it prints, like http://192.168.1.42:3000/control.
The ceiling goes dark after ten minutes
The Pi's screen-saver came back. On the Pi's desktop: menu → Preferences → Control Centre (called Raspberry Pi Configuration on older systems) → Display → Screen Blanking: off.
I need the Terminal but Skylight fills the screen
Plug the keyboard in and press Alt+F4. Skylight closes and the desktop is behind it. To bring Skylight back, unplug the Pi's power and plug it in again.
It says HTTP 403 or 401 at the top of the phone page
The free internet feed has closed to the public. Buy the radio (Part 1), or on the phone page under Source paste a different feed from this list.
It says “rate limited” at the top of the phone page
The free feed is busy. Skylight waits and recovers on its own. Nothing to do.
I plugged in a radio but it's not using it
Try another USB socket, then type the line from Part 3 again (press Alt+F4 first to get to the desktop).
Still stuck?
Paste this into ChatGPT or Claude and describe what you see, or open an issue on the GitHub Issues tab. Include the line at the top of the phone page.
I'm building Skylight, a projector that shows the real planes and stars above my house on my ceiling. Please read https://skylightceiling.com/llms.txt first, then walk me through it one step at a time. I'm not technical. Start by asking me what I already have. If you can't open links, say so and I'll paste the file.Questions people ask
Do I need to be technical?
No. You'll click through an installer, plug in cables, paste one line, and tap a web page on your phone.
Does it need the internet? A subscription?
Never a subscription. With the radio, planes work without internet; being online adds where each flight is headed and the satellites. Without the radio, it needs the internet.
Do I have to live near an airport?
No. Planes fly over almost everywhere, and the stars, moon and Space Station keep the ceiling alive on quiet nights. Closer to a flight path is more fun.
How dark does the room need to be?
Dark. It's a night-time thing. Lights off, even a modest projector makes the planes and stars glow.
Can I use a Pi or a projector I already own?
Yes. A Raspberry Pi 4 or 5 works. Any 1080p projector works if you can point it straight up.
Is it safe to leave on all night?
Yes. The Pi and radio are built to run all the time. Keep the projector's vents clear.
What about privacy?
Skylight only listens to the planes; it never transmits. It runs on your own Pi. It shares your approximate location with the free plane feed, and with the map service when you type an address. Once a day it also sends an anonymous count-me ping (a random id, the version, radio or not, which Pi), never your location. Switch that off on the phone page under System.
Does it update itself?
Yes. Early each morning it checks for a new release, installs it, and restarts. If an update fails it goes back to the previous version. To stop that, type sudo systemctl disable --now skylight-update.timer in the Terminal.
How can I help?
If you have the radio, share what it hears with adsb.fi: that's where the free feed comes from. And post a photo of your ceiling on the GitHub Issues tab; I'd love to see it.