I once toyed with an idea of putting a temp/rh/pressure logger on a RC
plane with an autopilot. It would climb on its own, gather data, come
back to the launch site and fly in circles until an operator turns on
a radio and guides it to a landing.

I decided against it because of legal issues. While I do not know all
the relevant laws, I am pretty sure that an amateur-built UAV flying
close to an airway (that's where my club is located) would be frowned
upon.

I am sure that unmanned balloons and rockets are subject to their own
regulations.

On the other hand, building a sensor package to be carried by an
ultralight or a kite would be relatively easy.

Bart


On Sep 14, 6:12*am, Anders Petersson wrote:
Hi
I have developed a system "Windsond" to gather local wind data at different altitudes in an easy way. This is done by launching a 60 liter helium balloon with electronics that transmits back sensor data as it ascends. On the ground, a laptop receives the data and displays diagrams of wind speed, direction and temperature.

The idea is not new, and weather balloons are indeed launched daily all over the world. The novel thing is the light weight and low cost, for a system adapted for altitudes up to 3000m. We use this for hot air balloons where we also recover the electronics again with a success rate around 80%.
More information and pictures hehttp://kiwiembedded.com/windsond/

From discussing with a glider pilot, it seems this could be interesting for your sport as well. But you also want humidity readings, right? I'm interested in your comments and what potential you see. Looking forward to hear from you either here or on email .

Thanks for your time,
/Anders Petersson
*Embedded systems designer