decoding Funcube data for school project

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decoding Funcube data for school project

Postby PE1JTG » Sun Oct 19, 2014 9:07 pm

Hello,

I am new to this forum and just starting with Funcube.

I am a teacher application programming in, mainly, C# and Arduino. On our school (ICT, technical, age between 17 and 21) we want to start a Funcube project. The goal is to make the rotation of Funcube visible. The first part will be to create a rotating object on screen. When this succeeds we want to take it a step further by putting a model of Funcube in a transparent globe and move it around by controlling stepper motors. For this we need to decode the raw Funcube data. I have taken a look at the data and it seems to be encrypted. Another option was to use the .csv WOD, however this seems to be incomplete since the Z+ and Z- solar panel data are missing (or are they..).

Is there someone who can tell me how the raw Funcube data is encrypted?
PE1JTG
 
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Re: decoding Funcube data for school project

Postby g4dpz » Mon Oct 20, 2014 7:16 pm

Hi,

To be strict about the data format, it is encoded, not encrypted as it is transmitted using Amateur Radio frequencies and has to be open for decoding.

The document which describes the format is given here:

http://funcubetest2.files.wordpress.com ... aft_13.doc

and the formulae for translation here:

http://funcubetest2.files.wordpress.com ... ons_b1.xls

The source code for decoding the data in Java is here:

https://github.com/FUNcube/fcdw_data

The main starting point for decoding the hex frames is here:

https://github.com/FUNcube/fcdw_data/bl ... essor.java

Look for the processHexFrame() method.

Quite happy to continue the conversation here or take it offline: dave at g4dpz dot me dot uk

Best wishes

Dave Johnson, G4DPZ
FUNcube Data Warehouse Developer
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Re: decoding Funcube data for school project

Postby PE1JTG » Mon Oct 20, 2014 8:14 pm

Hello Dave,

Thanks for the quick response and info, I'll take a look at it.

The reason I asked if it was encoded was that a text file I received from a friend of mine showed some 'strange' characters. Not your average alphabet and numbers.. hearts, smileys, etc.
PE1JTG
 
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Re: decoding Funcube data for school project

Postby g4dpz » Tue Oct 21, 2014 7:39 pm

Hi,

If it was a funcubebin file it's meant to be read by the FUNcube dashboard software.

I think one of the other developers has a utility program to transform it into hex.

I'll ask.

- Dave
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Re: decoding Funcube data for school project

Postby PE1JTG » Tue Nov 25, 2014 7:28 pm

Hi,

We worked it out. Well, we.. A colleague of mine came with the idea that it could be ASCII we saw in the funcube file.. Dave actually said it : '..transforming into hex.'. I'm almost to ashamed to admit it.. Never even occurred to me.. Possibly I was mislead by the 'normal' characters in the file. Whatever, perhaps the working day pressure, but it works. The students have investigated the file and are now developing software for it.

Controlling stepper motors with Arduino is also quite easy. So, to controlling a transparent globe will be in reach now as well.
PE1JTG
 
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Re: decoding Funcube data for school project

Postby g4dpz » Tue Nov 25, 2014 9:24 pm

Hi,

That's great news, don't worry, I'm made a few mistakes in parsing the data out of the file too.

The biggest problem we've had recently was with FC2 generating some anomalous data in the preamble in the
packet making it look like FC1. Fortunately, it's only happened once.

There was an article in The Amsat-NA Journal last year for testing Fox using a multi axis mechanism, I'll try to find it.

- Dave
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Re: decoding Funcube data for school project

Postby PE1JTG » Wed Dec 03, 2014 7:04 pm

Well, hm, almost there.. The data in the funcube apparently is not ASCII, but code page 850 or something... I thought I got it, but showing it in C# application does not show the right character found in the 850 table. This is basically where the problem is. The data is encoded in a format I've not out yet. To be continued.
PE1JTG
 
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Re: decoding Funcube data for school project

Postby PE1JTG » Wed Dec 03, 2014 7:12 pm

And 5 minutes later.. there you have it, the solution! I needed to read the line as a code page 850 line, which I didn't do. Perhaps this might be a good idea to share.. ??
PE1JTG
 
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