[amsat-bb] Re: PIC rotator control

Tue Oct 13 10:08:29 PDT 2009

Nice idea Gregg.  We do a few near space balloons each year and I have been
bugging some other folks ( because I don't write code ) to consider 2
projects:

1 - rotator control in a moving vehicle to keep a small yagi such as an
Arrow pointed at the APRS signal.

2 - antenna parking based on data from a home WX station such as those
commonly beaconing on APRS systems. 

I will copy the 3 of you, Marc, Andrew and Gregg off list with more details.

> -----Original Message-----
> From: Gregg Wonderly [mailto:w5ggw at cox.net] 
> Sent: October 13, 2009 11:33 AM
> To: Alan VE4YZ
> Cc: 'Marc Vermeersch'; 'Andrew Rich'; amsat-bb at amsat.org
> Subject: Re: [amsat-bb] Re: PIC rotator control
> 
> I'd like to suggest that such systems should have a compass 
> input from a GPS too so that as I'm driving mobile, I can 
> have such a rotator strapped in the back of my truck, and be 
> able to have it track the pass so I can hear it, and grab the 
> mic and talk if I need to.  I'd also use this for mobile ATV 
> work to keep a beam pointed at our ATV repeater.
> 
> Gregg Wonderly
> W5GGW
> 
> Alan VE4YZ wrote:
> > Marc, Andrew and the group... 
> > 
> > It has always struck me as being odd that we use a PC to 
> run a PC(PIC 
> > based tracker box), to run a rotator control box, to run a 
> rotator.  
> > Sure it works but the absurdity of this really hits home when you 
> > disassemble your shack to take it all out for Field Day or 
> an EmComm 
> > exercise.  I don't!  I leave the PC and LVBtracker at home 
> and take my 
> > good old 1990's preprogrammed PIC based TrakBox that does 
> the radio and rotators.
> > 
> >  http://www.tapr.org/kits_trakbox.html
> > 
> >  http://picasaweb.google.com/ve4yz.alan/TrakboxRebuild2004#
> > 
> > As I read you comments you are both querying the rotator 
> controller, 
> > not the rotators, to find out where the AL and EL are.
> > 
> > With the power of today's inexpensive netbooks or the OLPC is there 
> > not a solution where the "embedded system is the netbook"?  
> Then, all 
> > that would be required between the PC and the rotator is a 
> black box 
> > with relays to power the rotators and a small A/D interface to take 
> > the data from the pots and pass it onto the PC?  A black box easily 
> > assembled by most hams.  If open source, then others can do 
> whatever 
> > is necessary create mods for various rotator systems such as pulse 
> > counting for stepper motors instead of A/D etc
> > 
> > My 2 cents.... Alan
> > 
> > 
> > 
> >> -----Original Message-----
> >> From: amsat-bb-bounces at amsat.org
> >> [mailto:amsat-bb-bounces at amsat.org] On Behalf Of Marc Vermeersch
> >> Sent: October 13, 2009 6:45 AM
> >> To: 'Andrew Rich'; amsat-bb at amsat.org
> >> Subject: [amsat-bb] Re: PIC rotator control
> >>
> >> Hi Andrew,
> >>
> >> I have a PIC based solution currently in the prototype stage. 
> >> It uses a
> >> PIC18F4455 and drives a Yeasu AZ/EL rotor without the 
> Yeasy control 
> >> box.
> >>
> >> The PC sends information to the PIC 
> (RequestedAZ,RequestedEL) and the 
> >> PIC sends back status information to the PC 
> >> (RequestedAZ,RequestedEL,CurrentAZ,CurrentEL,Status).
> >>
> >> Everything is done by the PIC:
> >> - Control of the rotor motors based on either 
> move-every-n-seconds or 
> >> move-when-error-angle-is-greater-than-n
> >> - Measurement of the actual AZ/EL with 10-bit resolution
> >> - Parking when no signal has been coming from the PC in x seconds 
> >> -or- an explicit park command is received
> >> - Stall protection
> >> - Some horizon protection: EL cannot go below x when AZ is 
> y to avoid 
> >> pointing into my neighbors' bedroom.
> >> - Over the top rotor control (under development)
> >> - ...
> >>
> >> I'm using a PIC18F4455 and it is very well capable of 
> doing all that 
> >> and more. I have chosen this path for several reasons:
> >> - Eventually I want to run a tracking algorithm in the PIC too
> >> - To make the control loop shorter
> >> - To avoid dependence on the PC part specifically on 
> safety related 
> >> aspects like stall control and horizon protection.
> >> - To explore the capabilities of the PIC18
> >> - (Because it's my job to do embedded HW/SW)
> >>
> >> BR,
> >> --
> >> /\/\arc
> >>
> >>> -----Original Message-----
> >>> From: amsat-bb-bounces at amsat.org
> >> [mailto:amsat-bb-bounces at amsat.org]
> >>> On Behalf Of Andrew Rich
> >>> Sent: dinsdag 13 oktober 2009 12:22
> >>> To: amsat-bb at amsat.org
> >>> Subject: [amsat-bb] PIC rotator control
> >>>
> >>> Hello
> >>>
> >>> I am re-visting a rotator controller.
> >>>
> >>> I am curious, should I push the processing of the "compare
> >> and make a
> >>> decision" onto the PIC, or pull that function back into the PC ?
> >>>
> >>> PC is LINUX
> >>>
> >>> I/O is serial
> >>>
> >>> PIC is 16F877
> >>>
> >>> Andrew VK4TEC
> >>>
> >>> _______________________________________________
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> >>> author.
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> >> _______________________________________________
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> >> author.
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> >>
> > 
> > _______________________________________________
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> 