SharpSky ASCOM compliant digital focuser project

[Garbz (Chris)]

Again I'm not sure about the the PIC architecture, but I know typical AVRs have a bootloader reserved memory which is customisable in size using fusebits. If the program memory starts at the wrong location or is the wrong size compared to the bootloader then it will fail. It's easier on the AVR since the bootloader is at the end of the memory not at the start but it could very well be that the code is jumping to the wrong starting memory address.

In any case nearly every bootloader I've worked with can be configured in various ways and you'll find one specific way that is needed to work.

[jwoody (Jeremy)]

Hello everyone
Is it possible to use my sharpsky kit control box on a moonlite high resolution motor? Or is the pin out of the 9 pin plug different.

Thank you
Jeremy

[wasyoungonce (Brendan)]

Jeremy

Sharpsky pin configuration is exactly the same as Moonlite and robofocus systems. This I know I worked with Dave (the designer) testing this.

I use a sharpsky with a ML hi-res clutched stepper...works a treat.

Brendan

[jwoody (Jeremy)]

Thank you Brendan, I suspected it did (the pro version does ) but wasn't sure about the kit version.
Cheers for that
Jeremy

[dtrewren (Dave)]

Hello Jeremy,

Brendan is 100% correct.

SharpSky is pin compatible with MoonLite focus motors.

I decided early on in the design to make the D-type connection pin compatible. You may need to adjust the period per step setting in ASCOM setup window. I would start at a value of 8ms/step and then adjust to taste. If the value is too low the motor may skip steps and if the value is too large the motor will simply be slow. You may also need to tweak the backlash value to suit the MoonLite motor.

Brendan do you have some suitable values for Jeremy ?

Let us/me know how you get on.

Cheers,

Dave

[Shiraz (Ray)]

I just switched over to a Moonlite - currently using 40ms steps and 10 for backlash and it works fine if any help. On an f4 scope, I am using 9x6-step increments with the SGpro focusing software.

must say Dave that you did an excellent job designing this gear - mine has worked flawlessly since I got it and being able to use the controller with a Moonlite mechanism is icing on the cake. thank you.

[wasyoungonce (Brendan)]

I found at the initial period per step, 35ms, that the ML motor is-stepped. I had to adjust this to 50~60ms, for period per step.

Backlash...sorry not at lappy atm but ~10 steps is about right...although, this is a guess I suppose I should actually use a dial test meter and measure this.....Meh...no!

Edit:
Should also say that +5V is routed out unused pins on the DB9 connector so you can hook up a temp sensor near the motor, if you want. Of course the temp signal is also routed thu the DB9 as well. But these are unused pins on the ML system so this will not interfere.

[dtrewren (Dave)]

Evening guys,

Thanks for the positive feedback Ray, always nice to hear guys are enjoying the design and it is working well

As an aside if anyone would like to perform a SharpSky self build I am still more than happy to supply pre-programmed PIC microcontrollers. The beauty of microcontroller design is that the hardware is generally quite straightforward to build (see the schematic) - the days of complex discrete digital are long gone.

Cheers for the info Brendan ! The temperature sensor used for the SharpSky kit version is the DS18B20 single wire Dallas interface sensor. so if you are using a MoonLite motor a temperature sensor can be added in if you wish (quote Brendan). Power, ground & data is all you need - the SharpSky firmware will detect the temp sensor automatically and inform the client.

Cheers,

Dave

[Shiraz (Ray)]

Originally Posted by wasyoungonce

I found at the initial period per step, 35ms, that the ML motor is-stepped. I had to adjust this to 50~60ms, for period per step.

Backlash...sorry not at lappy atm but ~10 steps is about right...although, this is a guess I suppose I should actually use a dial test meter and measure this.....Meh...no!

Edit:
Should also say that +5V is routed out unused pins on the DB9 connector so you can hook up a temp sensor near the motor, if you want. Of course the temp signal is also routed thu the DB9 as well. But these are unused pins on the ML system so this will not interfere.

thanks for the info Brendan - have upped the pulses to 50ms.

if of any interest, the step size on this Moonlite Newtonian focuser is 4.1 microns, which is perfect for the 40 micron focal zone in my f4 scope. At 6 steps per focus unit (ie 25 microns), the SGpro software generates very nice v curves and focuses as well as I can.

[wasyoungonce (Brendan)]

Hi Ray, yep that's pretty good, but might be a little short on steps in CFZ when using filters. We know that shorter FL scopes require more steps in the CFZ simply because they have tighter CFZ's.

If this becomes an issue, the ML stepper is as Hurst motor. The std Hurst fitted to ML's is the LSG35012F76P , 3600 steps per rev. You can increase to steps in the CFZ by replacing the motor with either of these Hurst units:
A Hurst LSG35012E84P, 5400 steps per rev.
A Hurst LSG35012E90P , 7200 steps per rev.
A Hurst LSG35012E98P, 1440 steps per rev.

You would have to do the math on step size and steps per CFZ but suffice to say, if you have 40 in the CFZ using the std motor then you would double this with the 7200 step motor.

Of course, too small a step and it will become slow and probably unmanageable.

[jwoody (Jeremy)]

Sorry for the tardy reply but thank you all for the info, the moonlite works a treat with the Sharpsky kit.

A little off topic but.....could you make a DIY rotator using sharpsky kit? Perhaps some sort of belt drive system. Just thinking out loud incase you are wondering what the noise is.

[dtrewren (Dave)]

Evening Jeremy,

Excellent, very pleased you got everything working with the MoonLite - a very nice piece of kit beautifully made.

You could use SharpSky as a DIY rotator after all it is essentially a computer controller motor. The hardware could stay basically as it is. However, at the moment the driver exposes itself as an ASCOM focuser not a rotator so the driver would need re-work to expose itself as a rotator. Currently, the SharpSky focuser driver is only designed to operate as a single instance and having two focuser drivers operating simultaneously would cause some software confusion. So the options are to make a simple mod to the driver to allow two driver instances to operate together or re-work the driver more extensively to expose itself as a proper rotator instance.

Hope that makes sense ?

Cheers,

Dave

SharpSky Innovations

[jwoody (Jeremy)]

Hello Dave, thanks for the information.
I suspected that having two controllers would cause problems but thought there might be a simple way around it.
I shall do some more research......
Cheers
Jeremy

[Shiraz (Ray)]

Really grateful for any help. Had the kit SSF running fine under Win8.1 and then accepted the Win10 upgrade. Still went perfectly. However, Win10 fell over for other reasons and had to be "reset" which reloads the OS and turfs out all the apps (keeps data files though). Am in the process now of rebuilding the automated astro stuff and have everything running fine, except for the SSF. I have Ascom driver 3.15, client 1.17 and have loaded everything with admin priv. A DLL appears in the right place and the client says it is connected to the focuser, but the focuser just does not move - works alright with the rotary encoder though. Nothing doing with SGPro either. One thing I did notice was that the max step length is now 30ms -my vague recollection is that the original system allowed longer steps.

Can anyone think of anything I might do next or can anyone see what I have done wrong? - do I need to reflash the PIC to get it to work with the current software? Looks like I might be putting my old Vista system back into service if it turns out to be Win10 fussiness.. Thanks in advance. Ray

[dtrewren (Dave)]

Morning Ray,

Dave here (SharpSky designer).

That is an interesting problem, however all sorts of crazy stuff can happen when an operating system goes over.

You don't need to re-flash the PIC microprocessor - it has no concept of being connected to Windows or any other operating system for that matter. The PIC only sees the USB connection and only sees the driver and ASCOM interface.

First of all when you plug in the SharpSky controller do you get the characteristic noise (ding-dong) from the PC and the Link LED goes out ? This indicates the PC has identified the SharpSky controller as a generic HID device and subsequently enumerated.

Assuming the above :
Following a re-boot uninstall the driver via the windows control panel. Check the .DLL has been removed and if not delete the .DLL

Now re-install the driver as normal.

Try connecting using SGP - does SGP actually say that it is connected ?

Let me know how you get on and we will go from there.

Cheers & clear skies,

Dave

[Shiraz (Ray)]

Originally Posted by dtrewren

Morning Ray,

Dave here (SharpSky designer).

That is an interesting problem, however all sorts of crazy stuff can happen when an operating system goes over.

You don't need to re-flash the PIC microprocessor - it has no concept of being connected to Windows or any other operating system for that matter. The PIC only sees the USB connection and only sees the driver and ASCOM interface.

First of all when you plug in the SharpSky controller do you get the characteristic noise (ding-dong) from the PC and the Link LED goes out ? This indicates the PC has identified the SharpSky controller as a generic HID device and subsequently enumerated.

Assuming the above :
Following a re-boot uninstall the driver via the windows control panel. Check the .DLL has been removed and if not delete the .DLL

Now re-install the driver as normal.

Try connecting using SGP - does SGP actually say that it is connected ?

Let me know how you get on and we will go from there.

Cheers & clear skies,

Dave

thanks for the quick response Dave - really appreciated.
. I will not reflash the PIC - that's good
- get the "boing" on connection - it sees it as a USB peripheral (family something?) not actually in the HID list. I didn't wire up the link led.
- have done the uninstall - reinstall, reboot a few times to no effect. It seems to clear the DLL from the uninstall region OK
- SGP says it is connected to the focuser - seems quite happy, but just doesn't do anything
- I just fresh installed ASCOM 6.1 and SS software on my old Vista system with the same result
- also bypassed the USB HUB and connected a (brand new) USB lead straight into the SS box with no result.

I don't know enough to make sense of this, but it seems to me that everything ASCOM is working OK (the filter wheel, cameras, mount etc) and the box is working OK (heartbeat and via encoder) - there just does not seem to be any comms between the two. Just so I am clear, the ASCOM driver does everything necessary to interface between ASCOM6.1 and the box - there is no other lower level driver? If of any help, a while ago I tried using the latest software, but had to revert to an earlier driver to get it to work. However, that was two operating systems ago and those versions of the software are long gone. The current driver is not the software that I was running before it all went pearshaped - the max step size definitely was larger than the current 30ms.

another observation that may be significant is that after a fresh install, the first try to move causes the screen to flicker slightly as it does when working. thereafter it remains dead - as though the software is dormant and waiting for the box to tell it that the original move is finished maybe?

Anyway, don't sweat too much on this Dave - I have well and truly had my money's worth from this great bit of kit. Regards Ray

[dtrewren (Dave)]

Hi Ray,

Thanks for the analysis.

Sounds like there maybe something else not correct. As you have now tried on a Vista machine and are getting the result I suspect the issue is not with the new Windows 10 OS but something else.

As a matter of interest which PIC firmware version so you have installed ?

If you want to return the controller to me I am more than happy to have a look and sort out any issue.

Cheers,

Dave

[dtrewren (Dave)]

Hi Ray,

Looking back at my spreadsheet I see that your SharpSky unit goes back to 2012. Depending on whether you have updated the PIC firmware since 2012 there is possibly a driver dependency. This is not an operating system issue but a dependency between the driver and the PIC firmware.

I would re-flash the PIC firmware to the latest version from the website. From memory the latest version is V4.1, I will check when I go out to my workshop. I have a hunch this maybe the problem.

Cheers,

Dave

[Shiraz (Ray)]

Originally Posted by dtrewren

Hi Ray,

Looking back at my spreadsheet I see that your SharpSky unit goes back to 2012. Depending on whether you have updated the PIC firmware since 2012 there is possibly a driver dependency. This is not an operating system issue but a dependency between the driver and the PIC firmware.

I would re-flash the PIC firmware to the latest version from the website. From memory the latest version is V4.1, I will check when I go out to my workshop. I have a hunch this maybe the problem.

Cheers,

Dave

its still the original - I will try reflashing it.
Thanks so much Dave. regards ray

[Shiraz (Ray)]

woohoo!! You are a legend Dave. The reflash fixed the problem and the moon will set in a couple of hours.

Thank you very much.