Design for a Positioner with DiSEqC Decoder

H

harm lok

Member
Messages
26
My Satellite Setup
echostar / pace / aston
My Location
The netherlands
Does anyone have information or a diy design for a positioner with diseqc decoder. I think i will manage to build the motor controller en puls counter and also a stand alone system with a little controller. But i would like to have information about the decoding and detail information / tabel about the disecq codes. I have measured already the 8 bit paterns into a timed/pulsed 22 Khz. I think i can usethe filter from an old disecq switch. Maybe there are other suggestions for my goal : Build a posioner with a east/west degrees display. Maybe it is possible to make a adaptation to the vbox-2.
Thanks al lot already for all your help and suggestions.
 
Trust

Trust

Specialist Contributor
Messages
925
My Satellite Setup
1.8 m CM at SMR 1224 + Elev. with 7 lnb changer Ku (lin - circ) - Ka (lin - circ) C (lin - circ)
My Location
Nijmegen Netherlands
Does anyone have information or a diy design for a positioner with diseqc decoder. I think i will manage to build the motor controller en puls counter and also a stand alone system with a little controller. But i would like to have information about the decoding and detail information / tabel about the disecq codes. I have measured already the 8 bit paterns into a timed/pulsed 22 Khz. I think i can usethe filter from an old disecq switch. Maybe there are other suggestions for my goal : Build a posioner with a east/west degrees display. Maybe it is possible to make a adaptation to the vbox-2.
Thanks al lot already for all your help and suggestions.
Han , here you'll find the diseqC specs https://de.eutelsat.com/en/support/technical-support/diseqc.html
I rebuild several V- boxes with a Moteck SG2100 circuitboard to run dat V-box with a 36v= H2H rotor at Usals .
But very hard to make a actuator with polarmount running with Usals .
For that its nessesary to provide 38 pulses / 1º AZ movement . as you maybe noticed with a actuator the amount of pulses is different between the east and west section .
To get a correct E/W position in the display you need a rotary encoder at the polar axis of the polarmount .
Or with the pulses of a actuator , with a special algoritme according to that actuator and polarmount .
Member A33 (Sat4All) and I already started sometime ago with testing such algoritme , but did not finished it .
I also rebuild a V- Box with the elctronics of a Premium X diseqC rotor that was provided with a Led display on the rotor showing the same AZ position as the markings on the motor housing .
But also that display wont show the correct position when using a actuator .

Premium X mod.jpg
 
Channel Hopper

Channel Hopper

Suffering fools, so you don't have to.
Staff member
Messages
29,708
My Satellite Setup
A little less analogue, and a lot more crap.
My Location
UK
Does anyone have information or a diy design for a positioner with diseqc decoder. I think i will manage to build the motor controller en puls counter and also a stand alone system with a little controller. But i would like to have information about the decoding and detail information / tabel about the disecq codes. I have measured already the 8 bit paterns into a timed/pulsed 22 Khz. I think i can usethe filter from an old disecq switch. Maybe there are other suggestions for my goal : Build a posioner with a east/west degrees display. Maybe it is possible to make a adaptation to the vbox-2.
Thanks al lot already for all your help and suggestions.

Now, if only you could stick a larger actuator on the end

IMG_4398.JPG
 
H

harm lok

Member
Messages
26
My Satellite Setup
echostar / pace / aston
My Location
The netherlands
Han , here you'll find the diseqC specs https://de.eutelsat.com/en/support/technical-support/diseqc.html
I rebuild several V- boxes with a Moteck SG2100 circuitboard to run dat V-box with a 36v= H2H rotor at Usals .
But very hard to make a actuator with polarmount running with Usals .
For that its nessesary to provide 38 pulses / 1º AZ movement . as you maybe noticed with a actuator the amount of pulses is different between the east and west section .
To get a correct E/W position in the display you need a rotary encoder at the polar axis of the polarmount .
Or with the pulses of a actuator , with a special algoritme according to that actuator and polarmount .
Member A33 (Sat4All) and I already started sometime ago with testing such algoritme , but did not finished it .
I also rebuild a V- Box with the elctronics of a Premium X diseqC rotor that was provided with a Led display on the rotor showing the same AZ position as the markings on the motor housing .
But also that display wont show the correct position when using a actuator .
Again a lot off thanks for the suggestions and help. I have calculated the relation between the degree position and the extension of the actuator.
If someone has a schematic off by Moteck V-BOX II then i would modify this to make the pulses accessable for a little microcontroller with a dish degrees display. Maybe i can put it together in one box.
The algorithm is not that complex. But you can see it is far from lineair. Also the ( in my case with actuator mounted at left side ) the east side has a higher resolution then the west. Part off the original channelmaster design for good reslolution at east / west regions.
I have uploaded the diagram and the calculation. I have made a adjustable table for every individual situation . If someone wanted that file please send me a personal mail .It is not possible to upload the excel file to this forum.
After measuring the actuator length at the limits and also at 0 degrees it is a pièce of cake.
diagramdegreesactuator.jpg


Extention versus Dish angle.jpg
 
A

a33

Specialised Contributor
Messages
640
My Satellite Setup
XSAT410
Rebox RE-9000
My Location
NL
Nice going! And all in one equation! (I hadn't arrived there yet.)
Background in maths, perhaps?

I'm just missing the B-BB distance at the actuator Bolt, but that would not be difficult to incorporate I guess (using Pythagoras again).
See my drawing at this post: USALS for BUDs:
That would give a more precise relation to actuator counts, I guess.

(The H-distance in my drawing is always/normally zero, I discovered since, in my ignorance of actuator setups...)

Carry on!

Greetz,
A33

Edit: I'll just have to look into your angle delta: where is zero?
In relation to the "offset bolt" not always being exactly at the north/south line, and how to use that in your equation.
I did the calculation of all distances in a spreadsheet; not in one formula....
 
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A

a33

Specialised Contributor
Messages
640
My Satellite Setup
XSAT410
Rebox RE-9000
My Location
NL
Does anyone have information or a diy design for a positioner with diseqc decoder.
There are diy diseqc decoders.
There is/are diy positioners, IIRC.
I'd have to look for them.

NB. There are two separate kinds of diseqc USALS/GotoX commands, I discovered.

What would be your goal?
Receive (modified) USALS/GotoX command (not more than ± 60 degrees) and convert to actuator pulse count (using mount/actuator inputs)?
Or input all raw input data (LAT, LONG, satellite-longitude(s), and mount/actuator-inputs as per your drawing) in some kind of computer, and convert to actuator pulse count?

BTW I have not checked yet that my 'modified USALS calculation' (adding forward axis tilt to site latitude angle, see USALS Notebook ) is 100% accurate. It will at least be close, but I haven't checked if it is indeed 100% accurate...

greetz,
A33
 
Trust

Trust

Specialist Contributor
Messages
925
My Satellite Setup
1.8 m CM at SMR 1224 + Elev. with 7 lnb changer Ku (lin - circ) - Ka (lin - circ) C (lin - circ)
My Location
Nijmegen Netherlands
Did'nt have or find V-box schematics
At AVR Projects - Juraś-Projects you find also diseqc info .
Juras made also a schematic drawing from the Moteck SG2100 diseqc rotor in which I made some own extras .
Would be interresting to have a dish degrees display for that to .


schema Moteck Juras.jpg
 
H

harm lok

Member
Messages
26
My Satellite Setup
echostar / pace / aston
My Location
The netherlands
Did'nt have or find V-box schematics
At AVR Projects - Juraś-Projects you find also diseqc info .
Juras made also a schematic drawing from the Moteck SG2100 diseqc rotor in which I made some own extras .
Would be interresting to have a dish degrees display for that to .
Thanks for this , it is very straightforward.
My idea is to design a small processor (cortex 0) board with a little hardware and display that operates as an extension to the v-box to show the degrees display . Only sharing the pulses connected from the actuator to the V-Box. ( because at this moment it is my only actuator) Later on it would be nice to figure out the Diseqc databooks from eutelsat and add an power supply and a diseqc decoder to the proccesor board to build a complete diseqc controlled actuator . Maxim has a nice diseqc decoder circuit application and chip.

Maxim application Maybe i have to search and switch to another part of the forum ?
 
A

a33

Specialised Contributor
Messages
640
My Satellite Setup
XSAT410
Rebox RE-9000
My Location
NL
Just some links, when you are interested

diseqc decoder:
Is this one already linked somewhere? N0QBH Free to Air Satellite PIC Projects

positioner:
I believe on a german forum there is also another one (by an italian?); didn't look for that yet.

2 kinds of GotoX commands:

V-Box2 schematics: google posi14.pdf site:satelliteguys.us

I'm sure there is more, but this is what I could find the last hour. :confused

Greetz,
A33

As for topic and subforum:
I think you can ask moderators to split your post 41 in two halves, and split off the second half plus the rest of this topic to a new thread.
And suggest a new title for that.


Edited by @Lazarus to add: Done!
 
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Channel Hopper

Channel Hopper

Suffering fools, so you don't have to.
Staff member
Messages
29,708
My Satellite Setup
A little less analogue, and a lot more crap.
My Location
UK
Again a lot off thanks for the suggestions and help. I have calculated the relation between the degree position and the extension of the actuator.
If someone has a schematic off by Moteck V-BOX II then i would modify this to make the pulses accessable for a little microcontroller with a dish degrees display. Maybe i can put it together in one box.
The algorithm is not that complex. But you can see it is far from lineair. Also the ( in my case with actuator mounted at left side ) the east side has a higher resolution then the west. Part off the original channelmaster design for good reslolution at east / west regions.
I have uploaded the diagram and the calculation. I have made a adjustable table for every individual situation . If someone wanted that file please send me a personal mail .It is not possible to upload the excel file to this forum.
After measuring the actuator length at the limits and also at 0 degrees it is a pièce of cake.
View attachment 130589


View attachment 130591
In practice your actuator is going to have difficulty reaching the west extreme as per the radial diagram, unless the arm is infintely thin (and return the dish with polarmount bearing next to it), but well done for putting it onto paper.
 
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H

harm lok

Member
Messages
26
My Satellite Setup
echostar / pace / aston
My Location
The netherlands
Thanks for the many reactions and useful links.

After my calculation for angles versus pulses i have realized a parallel interface for the V-box sensor input.
Fist i tried to connect a opto-coupler but when i draw some milli amps from the V-box sensor connection the V-Box is showing an Err2 mission.
Unfortunately i have lost the satellite position settings stored into the V-Box because i have to reset the V-Box to get to work again.
After that i have choose a method that did not put any current from the V-Box.
V_Box_connection.jpg

I have placed a bridge receiver over the sensor pulse signal with a resistor 1:5 divider to bring down the pulse voltage.
This circuit does the job. It operates perfect without taken any effect on the normal V-Box operation.
I have connected the pulse to a cortex0 processor programmable from a free editor/assembler.
My next job is to program that will convert the pulses into the calculated degree , so i get a degree's display instead of pulse.
I have already added a F-ram for my future plan to make a complete disecq positoner.

scope_2.jpg

This is a screen save of the pulse from the rectified (V-Box in Action ) pulses and the pulse ready to be counted en converted.
If you have additional suggestions or remarks , please respond.
Will be continued ..
 
H

harm lok

Member
Messages
26
My Satellite Setup
echostar / pace / aston
My Location
The netherlands
Today i have setup the hardware on a breadboard , If there are other members who wanted to develop with the same hardware
you are of course encouraged to participate in construction your own display .

I use this free programming / debugging development for my nxp cortex 0 processor (lpc812)

NXP development suite (free) for cortex processors programming in C++

But you can also use the free Mbed environment for use with any compatible cortex board.

The board I have used is a older one but you can use this one , it is also Mbed compatible so you can use both platforms.

I have also added a payable lcd display to the processor from newhaven NHD-0216CW-AB3 LCD connected with a I2C connection. When you initialize the I2c port on universal i/o pins you have to pull the i2c bus to VCC with 2k2 (5V) or 1k5 (3V3) resistors.

Next step is the programming the algorithm in C++ and testing to get the prototype of the vbox degrees display running.
After that i will try the find some time to design a pcb to fit this display in a standard housing for this project.

8DAB6A8B-DAC8-4AA3-8E5B-2797D64CFA7A.jpeg
 
A

a33

Specialised Contributor
Messages
640
My Satellite Setup
XSAT410
Rebox RE-9000
My Location
NL
Well, these electronics are way above my head, but it would be nice to finally see a positioner that uses USALS for an actuator!

Will you be incorporating the B-BB (as in my drawing) as an extra variable? I guess it will win a little bit of accuracy.

The lash of an mount+actuator was a problem in the previous tests by trust and me; but hopefully that will not cause problems.
Otherwise, one would have to find some kind of programming that a satellite position would always have to be reached from a certain direction (maybe different directions, left or right from zero)? Or incorporating a lash from x.xx degrees? (Thinking about positioning bigger/heavier dishes.)
But maybe that is not the goal you have in mind..... For a smaller dish <1.5 meter maybe less relevant.

Greetz,
A33
 
H

harm lok

Member
Messages
26
My Satellite Setup
echostar / pace / aston
My Location
The netherlands
Will you be incorporating the B-BB (as in my drawing) as an extra variable? I guess it will win a little bit of accurac
rob.jpg
I have used your sketch to point to the additional offset. It is not the best accurate drawing but it is only for explanation.
The offset b is not to be ignored. The angle of the yellow triangle is greatly affected because the short rectangle side
becomes smaller. As a result, this offset also influences the position and thus the angle of rotation.i will include the offset
in the calculation
 
A

a33

Specialised Contributor
Messages
640
My Satellite Setup
XSAT410
Rebox RE-9000
My Location
NL
I'm not sure if we are talking about the same thing?

You write about offset a and offset b.
I was taking only one offset measure there: the hypothenusa from those two. That is, in my drawing, A-BB (Axis to BottomBolt).
In the mount design you can place the bottom bolt anywhere you like. That is even practical, when you want to reach extreme sats east, or west, and arrive at boundaries of the rotation range of the mount+actuator.
So the bottom bolt doesn't need to be opposite of the true south/north, and there is no reason to measure offset a and offset b separately.

With my B-BB I was referring to only the actuator clamp.
When the actuator is extended, distances T-B and T-BB will be almost identical.
When it is retracted, TB will be clearly a bit shorter than T-BB (T-BB being the hypothenusa).
When every pulse counts, in dish rotation accuracy, and you can just program it in, it would be foolish to neglect it, I would think.

Greetz,
A33
 
Channel Hopper

Channel Hopper

Suffering fools, so you don't have to.
Staff member
Messages
29,708
My Satellite Setup
A little less analogue, and a lot more crap.
My Location
UK
H

harm lok

Member
Messages
26
My Satellite Setup
echostar / pace / aston
My Location
The netherlands
kind of programming that a satellite position would always have to be reached from a certain direction (maybe different directions, left or right from zero)? Or incorporating a lash from x.xx degrees? (Thinking about positioning bigger/heavier dishes.)
But maybe that is not the goal you have in mind..... For a smaller dish <1.5 meter maybe less relevant.

Greetz,
A33
Position in any way is not a problem. I will store the count / angle in F-ram.
But we have to think about a the calibration when the disk is moved by wind.
A kind off automatic re-synchronization.
My idea is to store the limits counts / angles and based on the last position turn to the nearby limit position to re-calibrate.

Another idea is to combine the positioner with a signal strenght measurement.
But i have a little knowledge about hf-designs. We need a kind of conversion from signal strenght to a 0-5V voltage to input to the processors ad converter.
It would be nice to have a automatic sat-focus option.
Maybe some member has the diagram of this circuit in the lt8700.

It is always good to have a wish list for hobby projects . .
 
A

a33

Specialised Contributor
Messages
640
My Satellite Setup
XSAT410
Rebox RE-9000
My Location
NL
It would be nice to have a automatic sat-focus option.
If I recall right, my old (DVB-S) XSAT 410 receivers had such an autofocus function on board.
I myself never used it, because with my small dish at the time I didn't need it. And it led to slower satellite switching, IIRC, because of the autofocus procedure of the motor.
I haven't stored much about that in my brain, though.

Greetz,
A33
 
Llew

Llew

cerca trova...
Staff member
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14,933
My Satellite Setup
Triple Dragon, Dreambox 8000, Echostar AD3000ip, TBS6522,6925,6983 PCie cards.
Gibertini 1.25m motorised dish driven by the AD3000, with either Inverto BU Quad or Norsat / XMW Ka LNBs . SMW 1.05m + 3 other dishes. Speccy: Promax HD Ranger+
My Location
The Flatlands of East Anglia
There's a basic description of dish autofocussing in an old TV magazine as used in a Pace MSS501- scroll down to October 1996. It's covered in the Dish Drive Techniques article. Continues in the following month.


AFAIK, AutoPeak for focussing the dish was a proprietary system used in the Echostar 8700s, possibly earlier ones too. There doesn't seem to be anything shown as such in my SR8700 schematic diagram.
 
H

harm lok

Member
Messages
26
My Satellite Setup
echostar / pace / aston
My Location
The netherlands
There's a basic description of dish autofocussing in an old TV magazine as used in a Pace MSS501- scroll down to October 1996. It's covered in the Dish Drive Techniques article. Continues in the following month.


AFAIK, AutoPeak for focussing the dish was a propriety system used in the Echostar 8700s, possibly earlier ones too. There doesn't seem to be anything shown as such in my SR8700 schematic diagram.
Hello Llew ,
thanks for your suggestion.
In your remark you mentioned a SR8700 diagram ,I have a defective SR8700.
Is it possible to send me a copy of your diagram ?
If you use or used the SR8700 i think youre familar with the satfocus function. I have experienced it is very usefull when receiving weak signals.
 
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