Has anyone made bartels or Ek's box or similar

[bojan]

Originally Posted by mswhin63

Interesting site direct encoders interfaced to the PC, although it may require software development to make it compatible.

Could end cheaper as well.

This encoder still needs USB interface box (which is the purpose of Ek box btw), and then there may be the problem of compatibility with CdC and/or ASCOM driver.
These Renishow encoders are magnetic (there is radially oriented magnet on the shaft and magneto-resistive sensor with ADC to convert rotational position into digital format) with 8 to 10 bit resolution per rev, quite enough.
However, I do not think it will be cheaper solution at the end... those encoders may also inherently suffer from periodic error due to positioning of magnet .. which of course can be corrected in software.. but at the end the whole thing may be too complicated to implement.
I will stick to optical encoders and Ek (or equivalent) box :-)

[kinetic (Steve)]

Bob, Bojan, Simon,

sorry for the OT post, but which software do you guys use to
make your small PCB projects with?

I have always used Freeware/shareware apps like PIA and ExpressPCB.

My homemade PCB for ScopeDrive is a version I designed circa 2002
and I need to add in some features.
When I loaded up the old *.pcb file into the apps it wouldn't recognise
them. Not sure why, it might be because the app is now working
on WinXP and not on the original HD it came from which was Win95.
I may as well start from scratch with my 2002 version layout but
in a newer XP friendly PCB designer.
Any suggestions?

cheers,

Steve

[bobson (Bob)]

Steve,

You will have to wait for Simon to tell you, he made it for me.


bob

[DavidU (Dave)]

I use Protel for PCB's

[bojan]

Protel, all versions, from Easytraxt to Altium :-)

If you need anything, PM me and I will do it for you.

[kinetic (Steve)]

Thanks Bojan,

pm

Steve

[MrB (Simon)]

Yep, what Dave and Bojan said, Protel.
Nothing else comes close, and it's Australian.
Protel released Autotrax as freeware some time ago, though a DOS program, works fine in windows.
Due to it's popularity there's plenty of stuff out there for it. Most board manufacturers will still accept it's file format.
I have used most of the Windows versions of Protel(except Altium) and I always go back to the old DOS Autotrax(nice quick keyboard shortcuts) for boards only or Protel for Windows(for Win3.11, not freeware) if I need schematics too.

[bobson (Bob)]

I've been revisiting the ideas and pictures of Bojan's and Stive's design.
I noticed your Bartalised system drive is metal on metal on both axes?
I mean the motor shaft and the Alt and Az metal surfaces.
Something like Crayford focuser, am I right?

If so, how do you make enough tension/friction between two surfaces, enough not to slip?

cheers

bob

[bojan]

I do not have noticeable problem with slippage. The weight of the tube itself and the pressure of idler on the vertical drive - two strong springs takes care of this - are enough to prevent any such problems.
Also, the use of lubricant on those surfaces is not advised. I think that deliberate contamination with fine but hard sand (like the one used for mirror grinding or sand paper) reduces the possibility of slippage to the minimum (BTW, the so called grit wheel is/was widely used in some designs of printers and pen plotters.. with absolutely no slippage between paper and driving mechanism)
As I started to use the system, I developed couple of procedures I exercise routinely as a precaution because I have noticed that if I slew to and from couple of times between two objects far away from each other the scope does not end exactly in the same position(s) - somebody (Rod, I think) called this micro-slippage .
However, this is is not the major problem as I do slewing only to find the hard-to-find targets and I always start from nearby known object, where I reset the scope position (that means, if my scope is pointing to a bright star for example, I find it in the database and tell the program "you are here now"). Then I GoTo to the object of interest, if I do not know how to find it by other means (star-hopping)
If I move the scope manually for example to the opposite direction in the sky to watch something else, encoders are taking care that the new position is updated with sufficient accuracy for visual observation. Currently, I have them friction-coupled as well, but I am thinking of using timing belt (no slippage here)
I do not use my bartels system for deep sky AP (only for planetary and Moon... for DS I use EQ6), because I (still) do not have field rotator (supported by the software). But I am sure it can be used successfully, with guiding of course. One day.... maybe.

[bobson (Bob)]

Thanks Bojan,

I've been reading a lot lately about different systems but mostly about Bartels. I even joined their yahoo group to see whats available there, info, pics and so on. But I still can not find any website that explains step by step how to make this system to work with the dob.

For instance, I am building EK's box as you know, and its very easy to follow instructions on his website and make it from the scratch. And its all sorted nicely there.

Bartels website I am not sure what is what. Can it be built without buying it from him? What do you have to buy from him if you have to buy it?

Maybe its the design of the page or I can not figure out whats what and what do I need if I want to make my Dob find things and GoTo with Bartels.

Its a bit strange that no one yet posted some instructions here in IIS like the one for EK box.

Thanks

bob

[Rod]

Hi Bob,

Follow this link:

http://www.bbastrodesigns.com/StepperDoc.html

It will take you directly to Mel's manual. Scroll to the end of it and Chuck Shaw gives you a description of how he set up his system. I think his description is the most detailed I have seen.

I used this site a lot when I set up mine:

http://ngc1514.com/Computer/index.html

You can buy the board from Mel or follow his instructions and make your own. My local club made a set of PCBs based on the design here:

http://www.geocities.com/CapeCanaveral/9601/pcb.htm

A friend soldered it up for me so I did it with all local parts.

Mel's site takes a little getting used to. Many links to it take you half way down a page so if you scroll up you sometimes find what you need. If you put questions on the yahoo list he is very helpful.

There used to be a lot more sites around on the Bartels stepper system but I think many have moved to the servo system now- out of my price range.

You can still find the old sites using the wayback machine:

http://www.archive.org/web/web.php

Paste any dead links you find into the wayback machine and you will often find them archived here.

Hope that helps.

Rod.

[bojan]

Hi Bob,
Rob answered all your questions, so I have nothing to add :-)
Please ask anything you want to know and I will try to help as much as I can, and I am sure rob will do the same.
Good luck ! :-)

[bobson (Bob)]

Thanks Rod and Bojan,

I must be blind since I couldn't see the link for the steppers
I thought while I am waiting for some parts for my EK's box to see what Bartels box involves to make and then got confused with his website.

I like this website:

http://ngc1514.com/Computer/index.html

Very good info and pics.

Thanks again

bob

[mswhin63 (Malcolm)]

Hey you all,

I have had some good times with basic AP, So to get some improvement I am gonna make the EK. Found a PCB board that is similar, seems as though it is based on a standard serial interface.

Board diagram - http://www.olimex.com/dev/images/PIC/PIC-P18-sch.gif

Board can be purchaced from Dontronics - http://www.dontronics-shop.com/pic-p...ype-board.html

All the pin connections goto the prototype holes so slight changes can be done by removing some components.

I have only had a quick look but seems to be an easier way to do things.

[bojan]

Looks OK. The only possible issue is loading of the Ek HEX code..
Let us know how it went.

[mswhin63 (Malcolm)]

Thats alright, I also purchaced a programmer that can be used to load the PIC. Even if the programmer doesn't work I have a seperate programmer from my old days of PIC.

[bobson (Bob)]

Malcolm,

What do you plan to use for encoders?

bob

[mswhin63 (Malcolm)]

I am not sure as yet, am considering a 10,000 step system and mount it centrally or purchace a low cost 500 step encoder and mount them on the outside of the DOB base to give 50:1 gear ratio would give me more than 25,000.

Still reading the info on the encoders and EK first before considering my options.

[bojan]

Originally Posted by mswhin63

I am not sure as yet, am considering a 10,000 step system and mount it centrally or purchace a low cost 500 step encoder and mount them on the outside of the DOB base to give 50:1 gear ratio would give me more than 25,000.

Still reading the info on the encoders and EK first before considering my options.

Just make sure the EK firmware does not overflow with such a large number of steps.

Perhaps you should write your own firmware with larger registers..

[mswhin63 (Malcolm)]

As I haven't read a lot as yet, what is the optimal number of steps?

I will have a look later at modifying. ATM I am interested in getting it running. Gear hasn't arrive as yet.