Help, Learning Diseqc control

[pcrider]

diseqc

Its been quite a while since I posted here, but I've always had good luck getting help, so here goes again...

My latest hobby interest has become Diseqc control of satellite devices.

For those not familiar, Diseqc. "digital satellite equipment control". Its purpose is to send a signal along the same coax cable that recieves satellite signals from the dish. Allowing this signal to control devices like dish movers, LNB, or LNBF's, and LNB selector switches, for choosing which LNB is being used.

It can also control a Servo motor type feedhorn/lnb combination. This is my ultimate goal. Since new recievers do not include a linear servo control of any kind that I know of. The new units use only LNBF electronic switching. Very limited in my opinion.

I've read that a pic can be used, or a number of other micro controllers. In that case the signal is tapped from the coax, then "detected", and sent to the microcontrollers ADC for processing into ascii data that can then be used to program mechanical devices attached to the same micro.

I studied motorolla HC11 assmebler for a time, and got so I thought I could write a program in assembler. I never really had a project in mind so I let it slide. That has been years ago though, so I am basicly starting over.

Am I even on the right track?

I haven't programmed a pic before although I have a programmer, and plan to learn it. It would be nice to do the learning on one of the hc11 evaluation boards that I already have, and later port it to the pic, if need be. I have both the hc11evb, and the hc11evbu. With these I would have the advantage of an rs232 interface allowing me to view my progress as I go. (at least some of it) Not to mention a breadboard area to set up a detector circuit, if needed.

So finally it looks like, (hook the reciever to the micro via detector/ADC)-->(learn to program the ADC)--->(translate the results)--->(create a program to make use of the info)<--- thats a biggie!

Step one: hook it up to the micro, which one do you suggest? What circuit?

Step two: Learn to program the ADC, (at least prove step one worked then continue) I'll get back to you on this one.

I'm certain I've talked to much so I'll get off here.
Thanks for any help!
PcRider

PS: I've searched on diseqc at the pic website, as well as the interbet for several weeks now. Much info on what the results should be, not so much on how to do it.
I have most if not all the documents from EUTELSAT concerning Diseqc. I am in the process of reading as many as I can make time for.

 

[AlW]

diseqc schematics

Attached are a couple of files that do DISEQC using a PIC. This was done for a test fixture. Hope they are of use.

 

[AlW]

diseqc control signal

Here's the source code

 

[pcrider]

pic diseqc source code

Attached are a couple of files that do DISEQC using a PIC. This was done for a test fixture. Hope they are of use.

Thank you.
I'll study the schematics, and software closely. I certainly don't understand it all yet, but its a great starting point.

I have much to learn/re-learn.

PcRider

 

[mazzhammer]

Hello, I'm building a little diseqc commander using a PIC16F84 and the schematics taken from this forum.
I've just 2 questions:
1) the signal must be 0 average and oscillate from +2,5 to -2,5?
2) the pic only put out 0 +5 volts, how can I create +2,5 -2,5 travel?

Thank you in advance.
Massimo
Italy.