[amsat-bb] Re: PIC rotator control
ve4yz at mts.net
Tue Oct 13 08:35:14 PDT 2009
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.
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
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
> 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)
> > -----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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