[amsat-bb] Re: PIC rotator control

Andrew Rich vk4tec at tech-software.net
Tue Oct 13 04:50:14 PDT 2009


Do you convert

"067" from ascii to binary and then compare that to an A/D value ?

I have worked out how to do binary to ascii

Sometime I wonder if just programming in perl on the LINUX side might be 
just as easy

I think potentiometers are used on most rotators ?

Unless stepper motors have entered the scene ?


----- Original Message ----- 
From: "Marc Vermeersch" <amvm at skynet.be>
To: "'Andrew Rich'" <vk4tec at tech-software.net>; <amsat-bb at amsat.org>
Sent: Tuesday, October 13, 2009 9:44 PM
Subject: RE: [amsat-bb] 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
>> _______________________________________________
>> Sent via AMSAT-BB at amsat.org. Opinions expressed are those of the
>> author.
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