Introducing Windsond


Developer Anders Petersson is in the final stages of bringing to market his latest project, Windsond. Windsond is  miniature radiosonde which can give you an immediate view of local weather conditions at different altitudes.

Anders said, “The focus of Windsond is on portability and low operating costs makes it perfect for air sports.

An electronic sond (“radiosonde”) connects to a small helium balloon. While it ascends through different air layers, it transmits telemetry data to a receiver on the ground. The receiver consists of an antenna, USB device and a regular Windows laptop. At a specific altitude the sond detached from the balloon and falls back to the ground where it’s easily recovered for reuse. Special algorithms lets the user direct the sond to a suitable landing site.

A major point is the extremely low balloon payload weight. At only 12 grams (0.42 oz), a mere 30 liters of helium is used. This gives a low cost for helium and balloon, and allows the use of a helium canister as small as they come — 1.5 kg.


  • Measure wind direction, wind speed and temperature
  • Hygrometer to measure air humidity and dew point (additional option)
  • Barometer to improve the altitude accuracy from 100m to 7m (additional option)
  • Simple sond activation by pulling a tag. Sounds indicate when the sond is ready for launch.
  • Sond peak altitude configurable by user, also during flight
  • Maximum altitude 5-8 km (17-26 thousand feet)
  • Radio link with programmable frequency and transmission power.
  • Specially developed error correcting code for more robust radio link.
  • No heavy metal content for small environmental impact
  • Ths sond can detach from a ground anchor by itself, for remotely initiated launch.


Ground station

  • Review weather conditions even as the balloon ascends
  • Weather conditions are reported in graphical and text formats and exported to file in “Winds” format
  • Automatic averaging and interpolation of measurements
  • Follow the balloon live on Google Earth, right from launch to landing
  • Multiple sonds and multiple receivers are supported
  • Change settings with convenient graphical user interface
  • Keep another sond in the car to compare the positions of the balloon and the car
  • Load earlier soundings to revisit the measurements or replay the flight

Sond recovery and reuse

  • Specially developed algorithms lets the user choose landing site with better than 100m accuracy.
  • The coordinates of the actual landing site is known with 20m accuracy.
  • The sond is equipped with loudspeaker and powerful strobe light to make it easy to find. (These are activated when the receiver is close by.)
  • Battery life of 2-5 days allows recovery at a convenient time
  • Battery is rechargable with included charger

The regular price for Windsond is €795 excl VAT. There are discounts are available to some user groups. In particular, I would like to get some HAB enthusiast on-board to help me run some tests, give feedback on user interface and so on.”

For more information contact Anders Petersson at



The lengths I go to, to recover my payload : Fishing

Michael RubinsteinAdrian Dalca, MIT 2012
With great help from Martin McCormick – Flight to test noise reduction algorithms on Go Pro Hero 2 camera.

The story is picked up by Michael Rubinstein: “We launched on Friday, March 30 2012, near Albany NY. In a nutshell, the trajectory of the balloon was significantly different from the prediction (below) and the balloon landed in water, Buzzards bay, right off cape cod. It has made an amazing distance of about 150 miles over 4 states in 3 hours!
You can see the positions transmitted back from the balloon in the Google map below. After Southbridge, keypoint 16, the balloon has passed 60,000 feet at which points it stops transmitting until close to landing.

Remarkably, the capsule started floating in the bay transmitting back its location (you can see the drift motion by zooming into to the landing area). However, we weren’t able to retrieve it the first day and then the signal was lost. On Saturday noon, at the point where we were sure we had lost it, it suddenly started transmitting its location again, which allowed us to head back to the cape, hire a boat, and retrieve it!

We used UCambridge Landing predictor and Balloon trajectory forecasts at the University of Wyoming for predicting the balloon trajectory. In trying to avoid landing in the ocean, we travelled from Cambridge, MA west towards Albany, NY to match a predicted landing near Worcester, MA. We found a nice field near East Greenbush, 6 miles from Albany. We also notified the FAA of our launch and expected trajectory. The final launch was at 5:50 PM.

GPS coordinates were sent by SPOT every 10 minutes until it reached 60,000 feet, at around 6:57 PM, over Southbridge, MA (which indicated the balloon was going faster than predicted). By all accounts, we expected to lose the signal for 30-60 minutes, maybe 90 minutes at the outmost. By 9 PM, we had given up hope of a re-surfaced signal, but a signal appeared at 9:06 PM. Unfortunately, the signal came from Buzzard’s Bay.


At around 4pm on Saturday, we took a boat from the nearby Marion harbor, with the help of Captain John, and managed to recover the capsule close to Bird Island – a small island with a historic lighthouse. The capsule and electronics were soaked in seawater for 19 hours. We cleaned them by fully rinsing them in clean water and rubbing alcohol several times to eliminate the salt deposits, and finally we dried them with hairdryer, fan and rice. All electronics survived and are now fully functional.



Dave Akerman on BBC 2’s ‘Cracking the Code’

On BBC2’s ‘Cracking the Code’ this week, Dave Akerman is featured talking about his Raspberry Pi flights on HAB. This is available to UK viewers only or those who have worked out how to get BBC content from their location. The link is

This is available for 6 days after this post is made.

To find out more about Dave’s work including his most recent TARDIS Raspberry Pi launch go to