(extract from a mail on caracas ML)

Jose, do you think it would be possible to buy an helium tank ?
you usually rent those filled of helium, when empty take back the tank. you can rent them at balloon shops or at any weather observation lab. I have the necessary helium/air tap/mixer, so the bare tank will do. helium is not explosive, tanks do not need any special precautions.

if you have an address where i could rent one, i'll get in touch with them to rent it.

Valentin do you have a baloon ?
yes, 8 of 1.5 cubic meter balloons and one weather balloon (15 cubic meters) the small balloons can lift 100 grams, the big one can lift over 1kg.

What is the wifi AP based on ? An openbrick or something like that ?
wrt54g/openwrt/tinyhttpd (very scarse space to put html)

How long does it survive with embedded batteries ?
12v solar panel, no battery (reboots at night), the wrt54g is very good at accepting poorly regulated dc from 5v to 20v. a universal battery for laptop can also be used (valance and alike), providing one week of juice when there is not enough sun (as in helsinki).

Do you have one or do we need to get one ?
got all the hardware needed in a 2kg case.

What distance can it cover ?
the weather balloon is supposed to last one month or so at about 1km high.
travel distance should be a few hundred kilometers.

Have any url about the helsinki performance ?

• http://volt.lautre.net/sail/S4G1/

it was a one week cruise on a small sailing boat with a crew made of geeks.
the tagline of the project is : "you can't reboot a boat"

there is a video we made on board;

• http://volt.lautre.net/sail/S4G1/video.htm