Flight Software

I've been busy with the software to control handle the telemetry for RAMFly... 
Sadly (and as is often the case) I've spent a while battling with the development tools. 

Ramfly's current processor...

The main controller hardware is an Arduino (currently an Arduino Duemilenova - see right) but soon to be replaced with a Mini Pro.  The standard Arduino development environment is good, as far as it goes, but makes it a bit difficult to get 'proper' software engineering going for folk like me who appreciate a fully featured IDE to help manage things. Creating and managing multiple source files / libraries etc is just not its thing. The standard tool does a good job of managing the build/upload process, but the editor is (IMNSHO) clunky and confusing.
At work, I live in Netbeans,  so I took it upon myself to investigate whether it could be used to develop Arduino code. Google revealed a few articles and the Arduino website has a page on the subject but it's a bit dated and relates primarily to building a Mac environment... 

I discovered a netbeans plugin that's quite new but helps a lot. It works alongside the C++ Netbeans module. The installation instructions on the plugin homepage are excellent and the author, Jaques, is very helpful. The plugin wraps the compile/upload process very well (you just need to manually add "upload" as a makefile target for Netbeans). However, that left me looking for a terminal/serial monitor. There are plenty of serial 'console' apps that can do the job, but ideally I wanted something integrated...  Searching took me to the rs232 plugin at java.net .  This project looks like it has grander plans, but for now I just grabbed v0.2 of the above plugin, installed it into netbeans and it works really well. So now I have my familiar Netbeans environment, auto formatting, code completion, 'on the fly' syntax checking, automatic code builds and uploads and a serial console. Pretty cool.
But, and there's always a 'but', it seems to get things wrong sometimes. Incorrectly flagged syntax errors, and a makefile corruption that occurs randomly. I can't (yet) find what's corrupted, so I end up having to create a new project, import the source files and then rebuild. I don't think the plugin is involved but the Makefile provided maybe.
Still to do: The Makefile still rebuilds the entire library on every build (as does the standard Arduino tool). It doesn't take long but that's not the point ...

Receiving aerial

Had a go at making a YAGI:

its 3' long & the soldering on the element will need doing properly
The bars are not glued in yet either, but it does have a female BNC connector on the end

Auto pictures from camera

The Canon powershot A490 turned up & I managed to get the hack kit onto the SD card.

There is a standard script for automatically taking photos after a set time period, so I tried it looking out of the back window:

(must be pretty near the top of the 'most boring video' stakes!)
There were just under 500 pictures taken over 4 hours, at 1 shot / 30 sec, before the batteries ran out.  This was all with the screen on (I've not managed to get the script to turn it off yet) so should last for a 5 hour balloon flight.

Cameras

Asked around to see if anyone had a camera they didnt want any more.

Someone found this for us:

Its a 2Mp camera from a good while ago, with only a few drawbacks...

it doesnt seem to work & it weighs about 650g.  Might take it apart and see if there is anything useful we can harvest from it.

Looking at another balloon website, it was talking about the Canon A490 :

Only weighs 170g

& I see that it is one of the Canon cameras that you can hack with the Canon Hack Development Kit
http://chdk.wikia.com/wiki/CHDK
Seems you can program things like time lapse or 1 photo every 30 sec, just by adding a script to the cameras SD card

So I ordered one from ebay :)

Collecting temperature & pressure

Got a small board measuring pressure and temperature:

the PCBs are (L to R)
temp/press/altitude monitor
GPS
microSD card board
compass unit (not much good)

Arduino sketch for the temp/pressure chip works fine, sketch for GPS works fine, but I'm struggling to merge them so that it can log both

Then, might be worth logging everything to SD card as well as sending the data to be transmitted

Insulation

Found this polystyrene box at work

It's probably a bit big for what we need, but it's nice and thick.

Unfortunately, I weighed it & it's a fraction under 300g - I think we are going to have to be careful of our all up weight!

RAMFly can sing ....

Well actually, more like tweet (like a bird, not like a teenager...) 

I spent way too long again last night, but eventually I got a basic radio telemetry setup working. I can now transmit information a massive 1.5m across my desk. That's without antenna and other required things which should boost the range to many Km.

Ramfly transmitting dummy data across my bench - click to expand

Here you can see my receiver collecting strings from the RFM22B. The second line has a receive fault (but the spelling mistake is all mine ... :) This was at 50 bps, 100+ proves very unreliable. However, remember there are no antenna though. The blue/yellow band at the bottom of the image is called the 'waterfall' and allows you to visualise non visual energy. Yellow/Red indicates energy and the darker parts silence. You can see here a 1200Hz sound and 1675 Hz sound. These are the sounds produced by the SDR radio in response to frequency shifts and corresponding Upper Side Band (USB) frequency compared with the reference frequency. The better the transmission the brighter/narrower the yellow/red bands will be. Although you can't see very well, there are two vertical red lines (directly beneath the red scale markers). These have to be very precisely aligned with the yellow/red waterfall marks to indicate the two frequencies produced by the payload. The horizontal blue band is the gap between two transmissions.

Wanna hear ramfly sing? 

The good chaps on freenode #highaltitude were very helpful. I was labouring under a misapprehension about how to set up dl-fldigi for a couple of hours - very frustrating