[amsat-bb] Re: thought for a neat product, anyone seen one?

[Eric Fort]

well put and pretty much what I was looking at.  I also prefer the avr over
the pic so I'd looked at the AVRUSBKEY and  the gumstix line.  both have
definate possibilities.  I think the gumstix would be easier to build upon
as you are basicly carrying a tiny linux computer and everything has already
been implimented in linux but if you are most of the way there with the avr
that seems like something I'd really be interested in.  please let us know
how this progresses.  maybe a bunch of us could adopt a group project.

Eric Fort
AF6EP

On Mon, Nov 24, 2008 at 3:25 PM, Mark Vandewettering <kf6kyi at gmail.com>wrote:

>
> I have the same rig, and much the same idea.  I haven't gotten very far
> along with this idea, but
> here's where my thinking takes me.  I've implemented Miller's "Plan 13"
> algorithm in Python, and
> currently use it to plan all my satellite operations.  On any reasonable
> laptop, it runs many times
> faster than real time, even while running in Python, so it seems like
> overkill to carry a laptop
> with you to do satellite operations.  The laptop is expensive, bulky, and
> hard to use in the field
> while aiming an antenna by hand, has limited battery life, etc.   Clearly,
> a more limited computer
> can do all that we really need.     If you look at G6LVB's latest/greatest
> antenna tracker:
>
> http://www.g6lvb.com/Articles/LVBTracker2/index.htm
>
> you can see that he does all that you want using just a PIC
> microcontroller.   My own personal
> bias is against the PIC though: I prefer the Atmel AVR chips, and in
> particular have been having
> a great deal of fun with the Arduino microcontroller board.  I suspect that
> if I back ported my
> Python code into C and put it on the Arduino, I could still get an update
> rate approaching 1Hz,
> which should be good enough for the purposes we desire.   The Arduino also
> has a nice little
> piggyback ethernet board.   Here's what I imagine the usage is.  While at
> home, you plug this
> thing into your home network.  It then contacts celestrak or whatever, and
> automatically downloads
> the TLE for current amateur satellites.  You can then disconnect the rig
> from your home network, and
> it's ready to carry into the field.  A couple of buttons on the box allow
> you to cycle through
> satellites, giving the elevation and azimuth of the satellite.  The Arduino
> also has a serial port
> which we can hook to the FT-817, and use it to control the 817 with
> doppler.  It would be a pretty
> simple project, requiring three modules (arduino, ethernet shield and
> display) and a few extra
> buttons etc...   Total cost probably around $100 or so.  Could probably run
> off batteries for days.
>
> I probably won't get back to working on this until after the first of the
> year, but if anyone
> is interested, some enthusiasm might further motivate me to get the
> software working.
>
>        Mark
>
>