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  #1  
Old 20-05-2012, 02:23 AM
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dtrewren (Dave)
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SharpSky ASCOM compliant digital focuser project

Hello fellow imagers,

I thought I would share my focuser project with fellow imagers from 'down under'. I have had quite a bit of interest in the the project from Australia and have already send a few kits south of the equator.

The project is an ASCOM compliant digital focuser and comprises of the following key components :

- ASCOM compliant software driver tested with many popular client packages such as MaximDL, ImagesPlus, APT .....

- Control box based around a powerful PIC micro controller and custom PCB

- Stepper motor with reduction gearbox

- Aluminium beam coupler to couple motor & scope focuser

- Manual motor control with user variable rate

- Temperature compensation

The best way to see what the project is all about is to check out the website : www.dt-space.co.uk/SharpSky_Kit

Hope you like the project, will be very interested to hear what you think

Cheers & clear skies,

Dave (Bristol UK)
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  #2  
Old 20-05-2012, 09:35 AM
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wasyoungonce (Brendan)
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Hi folks.

I've been following this stepper motor system development for some time now, even built the original unit based on an ebay development card.

Dave add temperature compensation to this and refined the firmware/software.

I liked the unit so much (as did others) Dave had dedicated PCBs made and put it out in kit form which I snapped up for myself and another IIS user. Dave did a fine job with the PCB kit, just neat...the little things, like:
Routing the PCB Temp probe tracks to the a dedicated sensor jack and also thru the motor DB9 connector (so you can put the temp sensor near the focuser);
Routed the PCB motor DB9 connector so it was the same as Moonlite/Robofocus pin to pin compatiable and also routed these tracks to a header (if you want a different connector).

I don't often get excited about things and it would have to be special for me to do so...as big Kev used to say (for those old enough) "I'm excited"!

I'm running the SharpSky with a new Moonlite clutched motor system...works a treat. Good thing about the ML...you can change your geared stepper for ~$90USD for more/less step positional accuracy.

The best thing about this stepper controller...works with all ASCOM compliant focus software!

Future developments...well that's up to Dave to tell suffice to say.....there is more in the skunk works.
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  #3  
Old 21-05-2012, 02:34 AM
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dtrewren (Dave)
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Hi Brendan,

Many thanks for the very positive feedback very much appreciated. I have really enjoyed this project and that fact that lots of others have built focusers and are using them in the field makes it all the more satisfying.

For me buying new gear is always really nice but building something to do the job always makes me smile whenever I use it

Any imagers from 'down under' that are interested or have questions please drop me a message.

Cheers & clear skies,

Dave
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  #4  
Old 21-05-2012, 11:35 AM
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wasyoungonce (Brendan)
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Here are some pics of David's SharpSky controller up and running a ML stepper.

One of the neat thing about this system is not only the automatic but the manual control. It serves three proposes:
Manual in/out stepping by rotating;
Change number of manual in/out steps each knob movement makes, by depressing knob and rotating then re-depressing knob; and
Firmware update..depress knob when applying power.
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Click for full-size image (properties-tab.jpg)
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Click for full-size image (sharp-sky-client-manager.jpg)
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  #5  
Old 21-05-2012, 12:01 PM
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allan gould
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I had a look at this site and was extremely impressed - it really looks excellent.
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  #6  
Old 21-05-2012, 12:11 PM
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wasyoungonce (Brendan)
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I got 2 controller kits from Dave, one for David and myself...but alas I butchered my case trying to drill large holes for the temp and manual control connectors. I didn't as yet have a step drill, I now do!

Thanks to the design, cheap replacements available for $6 from element14. Crisis over.
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  #7  
Old 21-05-2012, 12:36 PM
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mswhin63 (Malcolm)
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Hi Brendan,

How do you go with products like APT or other software in driving the focuser. I use APT and it has focus controlling function in it and interested in operating it as one package. I also use EQMOD.
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  #8  
Old 21-05-2012, 12:53 PM
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wasyoungonce (Brendan)
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Just tried APT ver 1.71 (it's a little old) but focuser ran fine, no problems connecting and stepping. I have been mucking around for ages getting ML stepper, building etc ...just got it all running, no scope time yet...apart from bench runs.

I read EQASCOM pad works fine...somewhere in the UKAIO projects forum.

edit:
yep foundthe post, Dave the developer tried it all out with EQASCOM pad ok.

Just tried APT ver 1.93...runs sharpsky focuser sweet.

Last edited by wasyoungonce; 21-05-2012 at 01:24 PM.
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  #9  
Old 21-05-2012, 03:32 PM
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mswhin63 (Malcolm)
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Cool thanks Brendon, looks like a great project. Moving house at the moment so not enough resources to purchase anything as yet but will do. Couldn't be bothered building my own system for now.
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  #10  
Old 22-05-2012, 05:54 AM
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dtrewren (Dave)
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Hi Brendan et al,

Excellent, like the images - really cool to see the kit up and running, looks like you have done a fine job. All we all need now is some fine weather to get outside and do some imaging. Saying that the UK short nights are now here so the mount has been brought inside for a tune and some tlc.

If anyone has any questions or suggestions regarding the SharpSky focuser please drop me a message. Suggestions are always welcome so things can be improved.

Cheers & clear skies,

Dave
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  #11  
Old 22-05-2012, 01:49 PM
Poita (Peter)
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Nice, I haven't had time to build mine yet!
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  #12  
Old 26-05-2012, 09:56 AM
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wasyoungonce (Brendan)
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Quote:
Originally Posted by mswhin63 View Post
Hi Brendan,
How do you go with products like APT or other software in driving the focuser. .......
Malcom, and all...Dave has released a new driver for SharpSky focuser, which fixes a direction of movement issue with some programs like APT.

With the new driver, SharpSky direction can be reversed in the properties dialogue. Some programs, like APT, the direction of movement "in/out" was not the same direction SharpSky focuser would move. In focus control programs like FOCUSMAX this was not an issue as they have reverse direction movement control.

I tried APT with ShaprSky...worked fine..but I didn't notice the direction of travel...this attends to this issue.

New driver available here.
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  #13  
Old 29-05-2012, 01:27 AM
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dtrewren (Dave)
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Hello fellow imagers,

I have had a request or two for some close up images of the SharpSky board to give a better idea of what is involved when building a kit. As can be seen the board is relatively simple, no surface mounted parts or anything like that. The larger IC is the PIC microprocessor and the smaller IC is the Darlington motor driver.

Hope that helps

Cheers & clear skies,

Dave
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  #14  
Old 29-05-2012, 09:00 PM
garymck (Gary)
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Hi all,

just received my kit from Dave. I expected to get a box full of components, and to have to sort them out. Instead I got a box full of components, each in a seperate little plastic bag, with a printed identifying label on it and neatly packed. This alone will probably save me a heap of time in the build. Dave has also been outstanding in email support. Looking forward to getting it working. Took 7 days to get here in Melbourne.

cheers
Gary
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  #15  
Old 30-05-2012, 08:39 AM
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wasyoungonce (Brendan)
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Hi Gary...what ever you do ....use a step drill for the mini DIN holes....

I butchered my case trying to drill & file these. Anyway, element14 has same cases cheaply...I obtained a new one but with a flange lid as this suits me better for mounting.

Good things come from bad.....errrr that's what I tell myself!

Brendan
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  #16  
Old 30-05-2012, 06:02 PM
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dtrewren (Dave)
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I totally second that suggestion !

For drilling holes into plastic (like ABS) or other soft materials the step drill is invaluable.

For anyone not familiar with the tool here is a photo :

Clear skies,

Dave
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Old 31-05-2012, 01:01 AM
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I agree, I use stepped drills lots of time and well worth it. I also got my last lot from bunnings as well, although I still have my original one form nearly 10 years ago and is still going strong.
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  #18  
Old 31-05-2012, 02:28 PM
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wasyoungonce (Brendan)
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Finally finished my new case. This one has a flange lid which will make it easier to mount. Next to it is a std non-flange case.
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  #19  
Old 31-05-2012, 05:31 PM
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Dave,

If I'm reading your site correctly it looks like the kit contains the stepper motor and coupling but not the mounting bracket. Is it possible to post some images of the stepper motor, coupling and how it attaches to existing focusers?

Peter
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Old 31-05-2012, 06:01 PM
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dtrewren (Dave)
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Hi Peter,

Yes you are correct. The only component not included is the mounting bracket . I couldn't really get into fabricating brackets as obviously there are many scopes fitted with many different models of focuser so trying to create a range of mounting brackets would have been tricky to say the least. I have fitted the SharpSky focuser to both my Skywatcher ED80, ED120 and my custom widefield rig.

The 'original' web-site based around using a prototype board rather than a PCB
http://www.dt-space.co.uk/SharpSky/

has several videos showing the motor, bracket and fitting onto a SW ED80. The nice thing about using the flexible aluminium coupler is that it soaks up any small errors in the bracket fabrication. The motor has to be lined up reasonably well but if there is a small misalignment the coupler prevents the motor from damaging itself or the focuser mechanics.

If you want more detail please let me know

clear skies,

Dave
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