The Pi balloon: a Swiss mystery

If you’ve been wondering what happened to PIE, the Raspberry Pi camera-equipped balloon Dave Akerman launched on Saturday (with considerable hinderance from me, Eben and JamesH), Dave’s blogged about the launch and its aftermath. Most exciting of all, for us, was the new record Dave bagged with this balloon: it went even higher than his original Pi in the Sky attempt, and, at 40.35km (that’s a kilometer higher than Felix Baumgartner’s jump last year), now holds the record for the highest pictures transmitted in real time from an amateur device.

Eben, holding AVA, got an unfair head start when we launched by being nearly a foot taller than me (holding PIE).

When I was a very little girl, I was given one of those mylar helium-filled balloons, and lost it almost immediately. I was comforted by my Dad, who told me a new story every day about the country he calculated the ballon must be flying over. Five-year-old me never imagined that one day, I’d get to send up a globetrotting balloon and be able to track it for real.

After flying out across East Anglia, over the North Sea, Netherlands and Germany, PIE ran out of batteries somewhere over Switzerland in the early hours of Sunday morning. Dave believes it probably burst when it reached France later that day and warmed up with the heat of the sun, which will have made the balloon expand and rise. It’s unlikely it’ll be recovered, but we’re hoping some kind soul finds it and responds to the message Dave wrote on the payload. We had a fantastic time following PIE’s adventures, and were particularly tickled when someone in Stuttgart tweeted to let us know that they’d spotted it as it floated near the city!

You can thank Clive for this one.

PIE went up with one of our prototype camera boards, which Dave had switched to the auto setting. It performed brilliantly right up until it got into the stratosphere, when it started having trouble with the very pronounced contrast between the darkness of space and the brightness of the sun. This is something we can address in tuning for later flights, but it did produce a rather wonderful artefact which looked for all the world like a giant Raspberry Pi logo in space. (Sheer serendipity: this wasn’t planned.)

I, for one, welcome our new Raspberry Overlords.

PIE wasn’t the only balloon launched from that muddy field on Saturday. Anthony Stirk  launched AVA, which is the balloon Eben is holding in both pictures above. AVA burst over Austria, and the payload was recovered by a group of local high altitude ballooning (HAB) enthusiasts. And you’d have to be very enthusiastic to go and fetch AVA, because it had landed 1600m up, on the peak of a snowy mountain. The Slovakian team who went up to fetch AVA (equipped with ski poles and a radio antenna) sent back some pictures which were nearly as good as PIE’s pictures from space. Click the photo to visit Anthony’s blog, and to read the whole story.

Slovakian superheroes. From left to right : Peter Vittek, AVA , Radim Mutina (OM2AMR), Juraj Marsalik (OM1AMJ), and behind the camera Brano Janicek.

Alex Eames from RasPi.TV edited the long video stream of the couple of hours around the launch down to…just the exciting bit. (There’s no sound; your speakers aren’t broken!) I am running at the end through sheer excitement, not panic.

JamesH also took some higher-resolution video of the launch, which I’ll add here when it’s available.

I’ll leave you with a picture from Andy Potter, whose message momentarily had me believing that PIE had been spotted from the ground in the Swiss Alps. Thanks to everybody, especially Dave and Anthony, for a great weekend’s ballooning!

 


Guest post: more high altitude ballooning from Dave Akerman

Liz: Tomorrow, Eben and I are getting up at sparrowfart to go and stand in a field with Dave Akerman, where we will “help” him launch a balloon equipped with a Pi. This time the balloon, rather than going for an altitude record, is intended to travel a long distance laterally; we’re hoping it’ll make it to Poland in the 24 hours we have before its batteries run out. Here’s a guest post from Dave explaining what it’s all about, and showing you how you can track the balloon yourself, from home. See you tomorrow, Dave!

All being well I will launch the 5th “Pi In The Sky” this Saturday morning from Cambridgeshire. The intention is to get the balloon to float all day rather than burst, and the projected flight path takes it over Holland, Germany and into Poland. The batteries will last for 24 hours by which time it will be out of range of our radio receiver network anyway.

The payload will carry a model A Raspberry Pi, plus an Arduino Mini Pro, a UBlox GPS receiver, and 2 Radiometrix NTX2 transmitters. The latter will be on nearby frequencies primarily to avoid conflict with some other flights this weekend, but also to allow those with SDR (Software Defined Radio) receivers to listen to and decode the signals from both transmitters.

If you have an SDR and want to do this, check my article. If you’ve not tracked amateur high altitude balloons before, check the UKHAS tracking guide.

This will be one of 3 flights from the same location on Saturday:

Launch Announcement

On Saturday the 13th of April there will be three launches from the Cambridge area under meteorological balloons. Two of these (PIE5 and AVA) are configured to ascend to a certain altitude (>100,000 feet) and then float rather than burst. The expected path takes the balloons out of UK air space and continue onwards over Europe. The final flight (XABEN) will be a slow ascent and then a burst to land in Holland.

All balloons will be transmitting RTTY telemetry on the 70cms band.

The first balloon is flying a Raspberry Pi which will be transmitting live SSDV images back to the ground by a pair of transmitters to double the bandwidth. The data is RTTY 300 baud 8N2. The frequencies will be at 434.070 and 434.074Mhz. The balloon call sign is $$PIE.

The second balloon is flying a 70cms tracker on 434.450Mhz 50 baud 7N2, additionally once it enters air space where the airborne use of APRS is permitted a second APRS transmitter will enable with the call sign M0UPU-11.

The third balloon is callsign uXABEN, 434.350MHz, 470Hz shift, 7N1.

Live images from PIE will be displayed here

All balloons can be followed here

Anyone with suitable receiving equipment is welcome to assist tracking. We always welcome people joining the distributed network of listeners, instructions on how to receive these balloons is here.

Live chat and up to date frequencies and assistance will be on the #highaltitude chat room on irc.freenode.net. You can connect here

Live video from the launch site will be streamed here.


BBC: Cracking the Code

Last week’s Cracking the Code had a segment featuring a very familiar little computer, and a guy with a weather balloon whom you might just recognise. Isn’t it interesting how much more technical detail this kids’ show goes into compared to some of the adult tech news coverage we see on TV? Thanks to everyone involved – especially Dave!

[Update: looks like this video isn't available for viewers outside the UK - sorry if you're affected!]


Pi in the sky

I think more of you have emailed me about this than about anything else that anybody has ever done with a Raspberry Pi.

Near space Pi 1

Near Space Pi 2

Near Space Pi 3

What you’ve just looked at are, we think, the highest ever photographs transmitted live from an amateur device in the UK world. Dave Akerman hooked a Raspberry Pi with a webcam and GPS up to a hydrogen balloon, which got nearly 40km up (39,994m, to be precise) before bursting. This means that Dave’s is the first Raspberry Pi to visit near space (it returned unharmed, and Dave was able to recover it), and also means that Eben does not have to eat that hat he mentioned.

"And if you introduce a lighted spill to the neck of the test tube..."

Payload ready to go

If you want to learn more, visit Dave’s blog, where he has documented the flight minutely, to find out how he did it. He’s also put up a couple of Flickr sets: one full of images sent from the Raspberry Pi on its journey, and one of photos from the ground. Here at the Foundation, we’ve been reading his page on the project over and over, jaws on the floor. Well done Dave. We’re sending you a big virtual round of applause.