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POINT A CHEAP RADIO AT THE SKY AND YOUR CEILING BECOMES AN X-RAY THROUGH THE ROOF

A cheap RTL-SDR radio dongle and a Raspberry Pi turn your ceiling into a live map of every aircraft passing above you.

by Cameron Paczek

FULL CAD BOM FIRMWARE DOCS

DisplaysAutomation

Built withRaspberry Pi

difficulty
●●○○○
time
an evening
license
MIT
repo
repo ACTIVE3,315 stars

WHAT YOU’LL NEED

1
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COMPAREE VERDICT

Skylight is a rare build that looks ambitious but is actually straightforward: plug in an RTL-SDR dongle, run the Node app on a Raspberry Pi, point a projector at the ceiling. Aircraft broadcast their position, altitude, and identity on ADS-B, and a cheap RTL-SDR radio can receive it. Skylight decodes that and overlays it on a sky map showing the sun, moon, stars, planets and ISS in real time. The antenna is less of a problem than you would think — the developer says the dipole that ships with the RTL-SDR is plenty, because the planes you care about are nearly overhead. The projection setup is forgiving: the developer recommends a basic native-1080p LED projector for a dark room and says expensive laser units are overkill. If you live under a flight path this is an evening well spent. If you rarely see aircraft, the sky layer (stars, planets, satellites) still keeps the ceiling alive, but the planes are the show. The software is mature, the parts are off-the-shelf, everything is tuned live from a phone control panel, and the MIT licence lets you modify and share freely.

GOOD TO KNOW

  • —The repository includes TypeScript source, a Pi setup guide, Docker files and a clear parts list in the README.
  • —No 3D printing or PCB required — this is an assembly job.
  • —The software pulls flight data from an RTL-SDR receiver and renders a live projection layer.
  • —Instructions cover the Pi setup, software install, location and rotation settings, and troubleshooting.
  • —MIT licensed with no commercial restrictions.
  • —The README explicitly states a cheap 1080p LED projector is sufficient and a laser projector is unnecessary.

Parts to buy

4 items

From our check of the build. Exact quantities and part numbers are in the creator’s BOM.

  • Raspberry Pi 4 or 5 (64-bit OS)Find
  • RTL-SDR dongle (RTL-SDR Blog V3/V4/V5, RTL2832U)Find
  • Native-1080p projectorFind
  • Dipole that comes with the dongleFind

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Can I build this?

Printnothing required
BuyRaspberry Pi 4 or 5 (64-bit OS), RTL-SDR dongle (RTL-SDR Blog V3/V4/V5, RTL2832U), native-1080p projector, the dipole that comes with the dongle
ToolsSSH access to the Pi, text editor for config, ceiling mount or tripod for projector
SkillsBasic Linux command line, Pi setup, editing a config file. No soldering or flight-tracking expertise needed.
TimeTwo to three hours: one for software setup, one for antenna placement and signal check, one for projector alignment.
Cost$$ — dominated by the projector if you do not already own one; the README suggests a native-1080p LED projector at around 150 dollars instead of a laser unit.
SafetyLow risk. Secure the upward-pointing projector on its stand with tape and a safety tether, as the README advises. The RTL-SDR is receive-only. If you mount an antenna outdoors, follow local grounding rules.

Build at your own risk. Projects involve tools, electronics and sometimes mains voltage — follow the creator’s safety notes.

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Gallery

Start here

Navigation into the creator’s own docs — we don’t rewrite the guide, we route you to the source.

  1. 1.Clone the repository and read the README from top to bottom — it is the only documentation. (The README includes the full parts list, software dependencies, and config instructions.)
  2. 2.Install the RTL-SDR drivers and dump1090 on your Pi to confirm the dongle receives ADS-B.(dump1090 is the standard ADS-B decoder. If you see no aircraft in its output, your antenna placement is the problem.)
  3. 3.Install the app with the Pi setup guide, project the kiosk display onto your ceiling, and set location, rotation and brightness from the phone control panel.(Alignment is manual: set rotation and mirroring from the phone control panel and tune them against a real aircraft pass.)

Resources

Documentation, files and community threads for this build — we link straight to the original sources and never rehost the creator’s files.

KNOWN ISSUES

  • The developer says the dipole that ships with the RTL-SDR is plenty for planes overhead, but placement still matters — if dump1090 shows few aircraft, move the antenna closer to a window before buying anything.
  • ADS-B range is line-of-sight. If you live in a valley, surrounded by tall buildings, or far from flight paths, you will see very few aircraft even with a good antenna.
  • The projection needs a dark room to be legible. Daylight or ceiling lights wash it out completely.
  • There is no automatic north alignment. Measure which way your ceiling faces and set the rotation from the phone control panel; the on-screen compass helps you check it.
  • Projectors vary in throw distance and keystone. If your room is small or the ceiling low, check your projector can focus at that range before buying.
  • A Raspberry Pi 3B or Zero 2 W is display-only: the README says to cap the frame rate and use the web API instead of running dump1090 on it. A Pi 4 handles display plus local radio; the Pi 5 is only needed for the optional sky-camera tracker.

Do I need permission or a licence to receive ADS-B?

ADS-B is an unencrypted broadcast that aircraft transmit openly, and receiving it with an RTL-SDR is a common hobby; Skylight only listens and never transmits. Rules on radio reception differ by country, so check yours if you are unsure.

Will this work if I am not near an airport?

Yes, set your location in the control panel and it works anywhere. By default it shows aircraft within 3 miles, which the README calls what you could realistically see; if you are far from an airport, widen the Radius slider. Planets, stars and satellites keep the display alive even with no traffic.

Can I use a cheap projector or do I need a laser one?

A cheap one is fine if you watch in a dim or dark room. The README says a laser projector is only worth it for a lit room and recommends a native-1080p LED projector; low brightness is fine, even better. Check it is truly native 1920x1080, has a quiet fan, and shows HDMI on power-on.

Does this need internet or does it work offline?

The ADS-B reception from your own RTL-SDR is local. Sun, moon, stars and planets are computed on the device, but satellite and ISS positions use TLE data fetched from Celestrak and flight destinations come from the online adsbdb service, so those parts need internet.

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Discussion1

FROM THE COMPAREE TEAM

Over 3,300 stars since June 2026, and the README says a cheap LED projector in a dark room is enough — no laser unit needed. What room in your house would you point this at?

CompareeTEAM2mo agoedited

Practical notes from our verification: the README embeds a demo video of the projection and links the project site skylightceiling.com, where the creator announces a ready-made kit via crowdfunding. The software is a small Node server with a 2D canvas renderer, plus Raspberry Pi setup scripts that boot straight into a full-screen kiosk, and a phone control panel where every setting, including rotation, is live-tunable. On the radio side the README is relaxed: the dipole that comes with the RTL-SDR Blog V4 is called plenty, because the planes are nearly overhead, and you can even try the whole thing with no radio using a free web API. The projector advice is equally practical — an expensive laser unit is only worth it for a lit room; in a dim or dark room a cheap native-1080p LED projector works, as long as it is truly native 1920x1080, has a quiet fan, and shows HDMI on power-on. A Pi 4 handles the display and local radio; the Pi 5 recommendation is for the optional sky-camera tracker. Correction (4 October 2026): we re-checked this page line by line against the project's own repository, documentation and videos, and fixed errors in earlier versions.

Cameron Paczek

Cameron Paczek released Skylight in June 2026 to project the planes flying overhead onto a ceiling, with a reference build centred on San Francisco International. He is now preparing a ready-made kit, announced on skylightceiling.com.

GitHub

Star the project on GitHub

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