Firstly, thanks loads to everyone that has backed our project so far. Slowly, bit by bit we're getting closer. We just need a big push this last bit, so spread the word.
Massive thanks to everyone who has volunteered their time on the project so far as well.
The lights for the balloon take a lot of current which travels over 50m of cable and cannot be above 48V for safety, so we went for a multiplexing design. 2 150W DC-DC converters make everything smooth at the balloon end and the control is handled by an arduino with an XBee. There's a block diagram showing the design below.
First we made up a model to check the design will work OK with the XBees and the arduino.
Once that was all working OK, we cut out some PCBs and then populated them.
Then mount it all onto a board with the PSUs and plug it all in!
For a little more detail, more photos and the arduino and Eagle files, go to blog.luneproject.com