SEND A RASPBERRY PI TO THE STRATOSPHERE ON A WEATHER BALLOON
Send a Raspberry Pi to 30 km with a weather balloon, radio live photos back, and drive to the landing spot.
by Dave Akerman
ScienceOpen-hardware
Built withRaspberry Pi
- difficulty
- ●●●●○
- time
- a weekend-plus
- license
- GPL-2.0
- repo
- repo ACTIVE91 stars
●●●●○ · a weekend-plus · GPL-2.0 · 91 stars · repo ACTIVE
WHAT YOU’LL NEED
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COMPAREE VERDICT
Pi in the Sky is the tracker that turned Raspberry Pi high-altitude ballooning into a repeatable hobby. It radios GPS position and live images via LoRa or RTTY on 434 MHz while the balloon climbs to the stratosphere, bursts, and parachutes down, and it can sound a buzzer and flash a strobe below a set altitude to help you find it. The software is mature, GPL-licensed and documented by Dave Akerman, who uses it on his own flights; the tracker boards (PITS Zero, PITS+) are bought ready-made, and the README limits software support to board owners. What will waste your weekend is not the Pi - it is the regulatory side. Most countries require you to notify or get clearance from aviation authorities before launch, and outside Europe you must check whether the radio band needs a licence. There is no single BOM: you buy a weather balloon, lifting gas, parachute, tracker board, camera and batteries separately, and if the forecast shifts, the launch scrubs. The project is for someone who has already built a few Pi things and is comfortable with SD card images and SSH. If you have, and you have checked the local rules, this is the most credible open-source path to edge-of-space photography without a rocket.
IN THE REPO
GOOD TO KNOW
- —The tracker software is in the repo under GPL-2.0; the PITS radio/GPS boards themselves are bought ready-made (PITS Zero, PITS+), not built from published files.
- —There is no BOM — the docs list compatible hardware but you source your own balloon, helium, parachute, camera, and radio parts.
- —Most countries require clearance or notification to launch an unmanned balloon; the repo does not help with paperwork.
- —The code supports multiple Pi models and has live SSDV image transmission over 434 MHz LoRa or RTTY.
- —Recovery depends on a working GPS fix and your ability to track and drive to the landing zone.
- —The 434 MHz transmitter is licence-free in Europe according to the project; check local radio rules elsewhere.
Parts to buy
7 itemsFrom our check of the build. Exact quantities and part numbers are in the creator’s BOM.
Can I build this?
Build at your own risk. Projects involve tools, electronics and sometimes mains voltage — follow the creator’s safety notes.
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Start here
Navigation into the creator’s own docs — we don’t rewrite the guide, we route you to the source.
- 1.Check local regulations for unmanned balloon launches and confirm you need no clearance, or file for it if required.(This step blocks everything else and is the most common project-killer.)
- 2.Read the Pi in the Sky documentation to choose your tracker hardware (LoRa or RTTY, which Pi model). (The README names the supported boards (PITS Zero with Pi Zero, PITS+ with A+/B+ models) and links the installation guide on pi-in-the-sky.com.)
- 3.Source your balloon, parachute, helium, and enclosure from a high-altitude ballooning supplier.(The repo does not provide a BOM; you are assembling the list from the docs and other flight reports.)
- 4.Flash the SD card image, configure your callsign and frequencies, and bench-test GPS lock and radio transmission indoors. (Do not skip the bench test — a bad GPS or radio config will end your flight before it starts.)
KNOWN ISSUES
- Launching without regulatory clearance is the mistake that happens before you even inflate the balloon — check your country's rules first.
- Lifting gas quality matters: balloon-filling helium sold for parties can be diluted, which cuts lift. Use a lift calculator and buy the gas from a supplier that states its purity.
- If you lose GPS lock after launch, you lose the payload — test the GPS module outdoors with a clear sky view before flight day.
- The landing zone is wherever the wind takes it; if you cannot drive there (private land, water, mountains), you do not get it back.
- Radio rules differ by region: the project says its 434 MHz transmitter is licence-free in Europe, but elsewhere you must check whether that band and power are allowed from the air or need an amateur licence.
- The balloon will burst and the descent is fast; if your parachute does not deploy or tangles, the payload hits the ground hard.
Do I need a ham radio licence?
Not in Europe: the project says its 434 MHz UHF transmitter is licence-free there. In other regions, check your local regulations before you launch.
How high will it go?
It depends on balloon size, payload weight and gas fill; the repo does not cover flight planning, so use a balloon burst and lift calculator before launch.
What if I lose the GPS signal?
You lose live tracking. The last position you received narrows the search, and PITS can switch on a piezo buzzer and LED strobe below a set altitude to help you find a landed payload - fit them. Test GPS lock outdoors before flight day.
Can I launch anywhere?
No. Most countries require notification or clearance, especially near airports or controlled airspace. The repo does not cover the legal side — you have to research it yourself.
Community builds
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Discussion1
FROM THE COMPAREE TEAM
Dave Akerman's tracker software is GPL-licensed and has flown on his own high-altitude flights. What would stop you from launching one — the paperwork, the helium, or just finding a clear weekend?
Dave Akerman
Dave Akerman is a UK high-altitude ballooning enthusiast who writes about his flights at daveakerman.com. Pi in the Sky is the tracker board and software that grew out of that work, with the software released under GPL-2.0.
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- Information is provided without warranty and may become outdated as projects evolve. Prices are indicative bands only — always check the creator’s parts list for current costs.
- Building and operating any project is at your own responsibility. Protective equipment, safe workshop practice and compliance with local regulations are the builder’s responsibility.
CompareeTEAM2mo agoedited
Practical notes from our verification: the repository is the tracker software for the Pi in the Sky boards (PITS Zero with a Pi Zero, PITS+ with A+/B+ models), which are sold at ava.upuaut.net, and the README says software support is provided only to people who bought one of those boards. The repo was last updated in June 2024, so treat it as mature rather than actively developed. The software handles RTTY and LoRa telemetry, including SSDV images, and supports extras such as a piezo buzzer and LED strobe to help find the tracker after landing. The balloon, parachute and helium you source yourself. The single biggest surprise is that regulatory clearance is entirely on you — the README does not cover any country's rules or forms. If you have never launched a weather balloon before, expect to spend as much time on the paperwork and supplier research as on the Pi itself. 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.