Listening in on weather balloons with RTL SDR

sonde

Every day, twice a day, over 800 weather balloons are launched around the world at exactly the same time. The data transmitted from these radiosondes is received by government agencies and shared with climatologists and meteorologist to develop climate models and predect the weather. Near [Carl]‘s native Auckland, a weather balloon is launched twice a day, and since they transmit at 403 MHz, he decided to use a USB TV tuner to receive data directly from an atmospheric probe.

The hardware portion of this project consisted of building a high gain antenna designed for 162 MHz. Even though the radiosonde transmits at 403 MHz, [Carl] was easily able to receive on his out-of-band antenna.

For the software, [Carl] used SDRSharp and SondeMonitor, allowing him to convert the coded transmissions from a weather balloon into pressure, temperature, humidity, and GPS data.

Weather balloon payload that (almost) guides itself back to you

The biggest issue with sending expensive electronics into near space is trying to recover them. [Lhiggs] set out to solve this issue with his Senior project for a Mechanical Engineering degree. He figured that a payload dropped from 100,000 feet should be able to glide its way back to some predefined coordinates. Here you can see one of the tests, where the payload is guiding its descent using a parafoil.

Directional control is possible with a parafoil simply by shifting weight between the two supporting ropes. In this case [Lhiggs] designed the payload to hang from a pair of servo-motor-actuated arms. Since the payload already carries altitude and position hardware (such as a GPS, electronic compass, and altimeter) it’s just a matter of waiting for the target height before separating from the weather balloon, then using the servos to navigate to the landing zone.

Unfortunately the project was never fully completed. But you can see that he got pretty far. There is test footage embedded after the break showing the device being dropped from a plane.

[Read more...]

Checking out Mount Olympus from 38 km

The image above shows Mount Olympus in the center, with a tiny bit of the western suburbs of Thessaloniki, the second largest city in Greece, in the lower right hand corner. These two points are 70 kilometers apart, but we’re not seeing a picture taken from the International Space Station. This is a picture from the SlaRos project, a high altitude balloon launched last summer that ascended to 38 kilometers above Greece.

On SlaRos’ project page (Facebook warning), the team covers the hardware that went in to lofting a camera high above the cruising altitude of commercial airplanes. A GPS module tracked the balloon in real time and relayed this to a GSM module to the mobile command and tracking team.

There are a ton of high altitude pictures of Greece over on the project’s Facebook page as well as a time lapse video of the Grecian wilderness after the SlaRos payload landed. The payload spent a full night in a field before it was recovered, but we’re very glad the team was able to recover these awesome pictures.

Can a Kickstarter project actually build a space elevator?

It’s the stuff that Science Fiction is made of: an elevator that climbs its way into space rather than needing a rocket to get there. Can it be done? No. But this Kickstarter project aims to fund research that will eventually make a space elevator possible. They’re already way over their goal, and plan to use the extra funds to extend the reach of the experiments.

A complete success would be a tether that reaches into space, held taught by a weight which is pulled away from earth by centrifugal force. That’s not really on the radar yet (last we heard humans weren’t capable of producing a substance strong enough to keep the tether from snapping). What is in the works is a weather balloon supporting a ribbon which a robot can climb. The team isn’t new to this, having built and tested several models at University and then in a start-up company that closed its doors a few years ago. Now they’re hoping to get a 3-5 kilometer ribbon in the air and to build a new robot to climb it.

For now we’ll have to be satisfied with the 1000 ft. climb video after the break. But we hope to see an Earth-Moon freight system like the one shown in the diagram above before the end of our lifetimes.

[Read more...]

Only you can kick a child’s balls into space

We had a lot of fun with that title. Of course when you’re talking about launching a thousand ping pong balls into space there’s no end to the puns which can be made. But this is actually a fantastic initiative to get people of all ages excited about science and near-space experiments. [John Powell] offers school children the opportunity to send an experiment into space. He’s Kickstarting the next launch, which is scheduled to take place in September. This way each entrant can fly their project for free, then get the results and a certificate back once the weather-balloon-based hardware is recovered.

There is one size restriction for the program. Each experiment must fit inside of a ping pong ball. But you’ll be surprised what can be accomplished. [John] reports that the most simple, yet interesting project is to place a small marshmallow inside the ball. As it rises through the atmosphere it will grow to fill the entire ball, then be freeze-dried by the the extreme temperatures. Some are not so low-tech. There’s an image of a tiny PCB holding a DS1337 and some sensors. It’s an atmospheric data logger that will provide plenty of information to analyze upon its return.

[via Hacked Gadgets]

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