Topics

New set of goals for Losmandy- simplest solutions?


W Maxwell
 

I tried a blue pill build, but really had difficulties, so tried the prefab (Instep). That didn't really work out, so am returning with  new goals  and a few questions.

1. My GM8 is now about 20 years old and the motors may outlive me or may not. I would like to have a replacement before they die. Same for the 492 controller. I KNOW the mount will outlive me. Buying from Losmandy is pretty pricey.

2. I found an encoder set/Nexus cheap  which solves my primary purpose of gettingGoTo, so that is of little or no importance at this point.

I'm pretty confident in the 492. Is there a set of motors that would be as good, or preferably better, than the stock?

Going beyond that and replacing the 492 (thus keeping an entire working system intact to return to in case I go into the weeds..):


3. AP is my main thing, so focus is on accurate tracking. I realize seeing and the Gm8's worm are the biggest limit, but compromises between slew speed and tracking are a non issue.

4. Computer control over nudging and centering. I'd be happy with 32x, twice the 492/stock motors, and be able to control nudge speed via the computer (which the 492 can't do).

5. I don't need focuser, rotator,  or other accessory control.

6. WiFi or bluetooth would be nice so I could control centering, etc via a tablet or phone. Not essential though.


What would be the simplest route to that end? 


1. A pre assembled "blue pill", MKS Gen-L V2.0, or pre-assembled Mini PCB??
2. with option above, which motors  ?
3. with option 1 and 2 , which stepper drivers   ?

I realize there are a myriad of options, but I think that is what derailed me before.  I would probably have more success if I had a defined game plan with a more fixed set of hardware and could then focus on getting those pieces working together.  Once I get it running and understand it maybe I'll tinker/refine later. Mechanical solutions, like making motor mounts and boxes for the electronics, aren't a big deal. Electronics are my weak point.

If I could impose on someone to give me a possible set of the above options that would accomplish the above goals I would be forever in your debt.


Henk Aling
 

I found the Wemos D1 R32 + CNCv3 easy to build.  I just use the two motors with mode switching and Bluetooth, controlled by my cell phone or by Ekos on a Pi by USB.  The hardware is super easy and the SPI needs extra wires.  If you search my threads you will find the details and motors.  The MKS Gen-L v 2.0 may not need SPI wires and might be even easier.  


W Maxwell
 

<sigh>


W Maxwell
 

Perhaps I was not clear in my request.

If I have a stock Losmandy GM8 and wish to replace the stock 492 and motors with something that can
1. move up to 32x via laptop control
2. Don't care about or need full GoTo
3. Want the best tracking performance
4. Want it as close to prefab as humanly possible

What do I get:
1. What board?
2. What stepper drivers for the above choice?
3. What motors with choice 1and 2?


Could someone kindly suggest a specific combination of these pieces that would fit my intended goals?


W Maxwell
 

I really do appreciate the response Henk, but this only adds to the confusion.

1. The Wemos D1... on the Wiki is listed as "experimental" and as such I ruled it out.
2. Terms which are probably quite simple to those in the know, but otherwise confusing only adds to the sense of walking on quicksand, like: 
    -motors with mode switching
    -Ekos (my google search led to to 2 pages of everything from software management to a " a minimally invasive system for dissolving thrombus")
     -SPI

Maybe the info I am hoping to get looks like this:

1. I have a GM8
2. I do AP and wanted good tracking
3. I used this board because it was the most pre-assembled
4. I use these motors
5. I used these stepper drivers

People have told me that going the "build the blue pill" was probably the hardest route. I am looking now for the easiest route. The all prefab route (Instein) hasn't worked in that I never got it and am trying to get my money back.

I have shown this response to 6 different people and the only one who had any idea what you were talking about was an electrical engineer. Its probably really simple and people may just say I need to digest the lingo and not be spoon fed, but I'm just trying to come up with something to take pictures. I don't mind investing time to understand the concept, but I've been at this for weeks and it still feels like I'm swimming through jello.


Khalid Baheyeldin
 

On Thu, Oct 15, 2020 at 11:44 AM, W Maxwell wrote:
If I have a stock Losmandy GM8 and wish to replace the stock 492 and motors with something that can
1. move up to 32x via laptop control
2. Don't care about or need full GoTo
OnStep provides 32X and faster, so you get that if you replace the motors with steppers.
You also get Goto. It is up to you if you use it or not.
If tracking is all you need, you turn on autostart tracking, and forget about gotos.

3. Want the best tracking performance
OnStep is pretty much accurate. Tracking accuracy depends on many things.

4. Want it as close to prefab as humanly possible
Does not exist in OnStep, unless a member is willing to help you out with brackets
for mounting the motor, and puts together a board for you.

What do I get:
1. What board?
Depends if you will be putting it together yourself, or someone will help you with soldering
and such.

Even if you get the FYSETC S6 (full blown options including heaters, ...etc.) you still have
to wire things yourself (to the motors at a minimum).

2. What stepper drivers for the above choice?
These are the motors that are most proven to work with various OnStep mounts of GM8's size.

https://www.omc-stepperonline.com/nema-17-stepper-motor/Dual-Shaft-Nema-17-Bipolar-09deg-44Ncm-6248ozin-168A-28V-42x42x48mm-4-Wires.html

3. What motors with choice 1and 2?
There is no realistic option for "OnStep tracking only" or "none Goto OnStep".


Khalid Baheyeldin
 

On Thu, Oct 15, 2020 at 12:03 PM, W Maxwell wrote:
1. I have a GM8
2. I do AP and wanted good tracking
3. I used this board because it was the most pre-assembled
4. I use these motors
See my earlier response. Motors are a known quantity.

5. I used these stepper drivers
Depends on what board you choose, and the motors too.
(Now you see why this is not a straightforward question, since some parts depend on
answers to other parts).

If you ended up soldering the Blue Pill board, then use the TMC2130.
If not, then see below.

People have told me that going the "build the blue pill" was probably the hardest route.
You seem to have friends that can help. Show them the detailed instructions for the Blue Pill, and they will be
able to solder it. I had almost no electronics experience before OnStep but I was able to design the Blue Pill
PCB, and put it together, with help from friends.


Dave Schwartz
 

While OnStep's tracking rate can be quite accurate, if you enable autostart tracking and then unlock the axes, push-to, lock axes and use an app or hand controller to frame, you can only use static tracking rates and there will still be errors or drift due to atmospheric refraction unless you do autoguiding.

One of OnStep's features to further improve tracking is dual-axis full refraction compensation but you can only take advantage of that if OnStep knows both where it is pointing on the sky and where it is located on the earth. That requires that it know the time, date, latitude and longitude, that you do an alignment and that OnStep be in charge of all movement.


On October 15, 2020 12:08:10 PM EDT, Khalid Baheyeldin <kbahey@...> wrote:
On Thu, Oct 15, 2020 at 11:44 AM, W Maxwell wrote:
If I have a stock Losmandy GM8 and wish to replace the stock 492 and motors with something that can
1. move up to 32x via laptop control
2. Don't care about or need full GoTo
OnStep provides 32X and faster, so you get that if you replace the motors with steppers.
You also get Goto. It is up to you if you use it or not.
If tracking is all you need, you turn on autostart tracking, and forget about gotos.

3. Want the best tracking performance
OnStep is pretty much accurate. Tracking accuracy depends on many things.

4. Want it as close to prefab as humanly possible
Does not exist in OnStep, unless a member is willing to help you out with brackets
for mounting the motor, and puts together a board for you.

What do I get:
1. What board?
Depends if you will be putting it together yourself, or someone will help you with soldering
and such.

Even if you get the FYSETC S6 (full blown options including heaters, ...etc.) you still have
to wire things yourself (to the motors at a minimum).

2. What stepper drivers for the above choice?
These are the motors that are most proven to work with various OnStep mounts of GM8's size.

https://www.omc-stepperonline.com/nema-17-stepper-motor/Dual-Shaft-Nema-17-Bipolar-09deg-44Ncm-6248ozin-168A-28V-42x42x48mm-4-Wires.html

3. What motors with choice 1and 2?
There is no realistic option for "OnStep tracking only" or "none Goto OnStep".

--
Sent from my Android device with K-9 Mail. Please excuse my brevity.


W Maxwell
 

Thank you for the responses. Let me try a different approach.

1. MKS Gen-L V2.0
2. Dual shaft nema 17 bipolar .9 deg motors
3. What stepper drivers?


Can combination of 1 and 2 be directly bolted 1:1 or does it require belts and pulleys?

If the above does not include belts and pulleys, then these two variables are now fixed and un-movevable for me. If it does require belts and pulleys, then I am back to square one again.

I think this has been the problem for me. Too many moving options that never seem to coalesce. I just want to bake the cake, but get bogged down following the recipe because all the  ingredients change with the choice of flour, the choice of eggs, the choice of heat in the oven.....

Someone has to have made some combination for a GM8 that worked or for that matter with a host of other common mounts. Maybe what I'm looking for is a complete recipe with "bill of materials" from start to end, like "here is a recipe for  this mount, this board, these drivers, and these motors". Have 10 recipes for different combinations. Have 100, but have  the variables from start to end for each particular build combination. I really think this would make this more user friendly. Otherwise it becomes like Linux. People just want an OS that isn't Microsoft, but get bogged down "kernals" and "compiling"  and "blocking an interrupt context".. Then there's Debian, Ubuntu, Red Hat...Most people just want to check their email.

Some people love to tinker and play with all the variables. Some cooks like to create their own recipes. If I tried to bake a cake from scratch I would have the same abysmal level of success I'm having putting together an Onstep.


Jochen.Siegfried@t-online.de
 

Hi Khalid

this post answered my question according on how to connect a stepper motor to a stepper driver. Good !

 

But how to change Microsteps on a LV8729 Driver ?? Close to the driver there is one row with three pins. There is a jumer that can be moved.

I use STM32 blue pill, driver is LV8729 or at the moment DRV8825. For DVR8825, as it is now, the jumpers for both drivers are set to 3/2 and 2/3 means that the jumper connects pin 2 with pin3 for both drivers !

 

How do you set the jumper for 32 steps an the LV8729 ???

 

Thank you very much for your help !

Ferris

 

 

 

-----Original-Nachricht-----

Betreff: Re: [onstep] New set of goals for Losmandy- simplest solutions?

Datum: 2020-10-15T18:08:25+0200

Von: "Khalid Baheyeldin" <kbahey@...>

An: "main@onstep.groups.io" <main@onstep.groups.io>

 

 

 

On Thu, Oct 15, 2020 at 11:44 AM, W Maxwell wrote:
If I have a stock Losmandy GM8 and wish to replace the stock 492 and motors with something that can
1. move up to 32x via laptop control
2. Don't care about or need full GoTo
OnStep provides 32X and faster, so you get that if you replace the motors with steppers.
You also get Goto. It is up to you if you use it or not.
If tracking is all you need, you turn on autostart tracking, and forget about gotos.

3. Want the best tracking performance
OnStep is pretty much accurate. Tracking accuracy depends on many things.

4. Want it as close to prefab as humanly possible
Does not exist in OnStep, unless a member is willing to help you out with brackets
for mounting the motor, and puts together a board for you.

What do I get:
1. What board?
Depends if you will be putting it together yourself, or someone will help you with soldering
and such.

Even if you get the FYSETC S6 (full blown options including heaters, ...etc.) you still have
to wire things yourself (to the motors at a minimum).

2. What stepper drivers for the above choice?
These are the motors that are most proven to work with various OnStep mounts of GM8's size.

https://www.omc-stepperonline.com/nema-17-stepper-motor/Dual-Shaft-Nema-17-Bipolar-09deg-44Ncm-6248ozin-168A-28V-42x42x48mm-4-Wires.html

3. What motors with choice 1and 2?
There is no realistic option for "OnStep tracking only" or "none Goto OnStep".



W Maxwell
 

On Thu, Oct 15, 2020 at 10:19 AM, Dave Schwartz wrote:
While OnStep's tracking rate can be quite accurate, if you enable autostart tracking and then unlock the axes, push-to, lock axes and use an app or hand controller to frame, you can only use static tracking rates and there will still be errors or drift due to atmospheric refraction unless you do autoguiding.

One of OnStep's features to further improve tracking is dual-axis full refraction compensation but you can only take advantage of that if OnStep knows both where it is pointing on the sky and where it is located on the earth. That requires that it know the time, date, latitude and longitude, that you do an alignment and that OnStep be in charge of all movement.
Understood. Let me reframe the goal:

-. Replace my 20+ year old 492 and motors before they die with something that does what the stock 492/motors do, but controllable via laptop.

You can't center, or re-center a target with a 492 via a laptop, at least not at anything faster than guiding correction speed, untess you are at the mount pushing buttons on the 492.

All else, slightly fast slew speeds, wifi/bluetooth et al,  is a bonus above this basic goal.


W Maxwell
 


Maybe I'm just looking for a solution that is now way more involved than what I really need at this point. Since my main concern are my motors..they have spend 2 decades running all night for months at a time..:

What are good replacements for the stock motors that will work with the 492 system?

Obviously I will also try this post at the Losmandy group.

I could buy from Losmandy, but there has to be an option that is cheaper than that. No point replacing used motors with used motors, so the used option wouldn't really serve my needs.


Khalid Baheyeldin
 

On Thu, Oct 15, 2020 at 01:45 PM, W Maxwell wrote:
1. MKS Gen-L V2.0
2. Dual shaft nema 17 bipolar .9 deg motors
3. What stepper drivers?
Usually the TMC2130, as the Wiki page for the MKS Gen-L says (under Choice of Steppers).
They will work if the steppers will be running below 1.2A or so, which is usually the case.
See the Wiki for the specific TMC2130 versions.

Can combination of 1 and 2 be directly bolted 1:1 or does it require belts and pulleys?
The showcase page has some examples for the GM8 on how people did it.

I think this has been the problem for me. Too many moving options that never seem to coalesce.
Agreed. Take your time to digest the info. How to eat and elephant: one bite at a time. Never all at once.
I was exactly like you for months. Just trying to know the terminology: what is a header? What is a pad?
What is a resistor array? Is it the same as a resistor network? Does that component care about polarity
or it does not matter? What is a driver? And so on.

If you persevere, and get someone to help with some tasks, I assure you it will be a very rewarding
project. I know first hand ...

Someone has to have made some combination for a GM8 that worked or for that matter with a host of other common mounts.
Yes.

I pointed you before to where you can find links to other GM8 on the showcase page.

Otherwise it becomes like Linux. People just want an OS that isn't Microsoft, but get bogged down "kernals" and "compiling"  and "blocking an interrupt context".
That is a misconception. This has not been the case for at least 15 years.
I have been using Linux for that long as my desktop, and never needed to compile anything.
There are other concerns (e.g. does your applications have Linux versions, or equivalent, or not), but not the usual tropes.

Then there's Debian, Ubuntu, Red Hat...Most people just want to check their email.
True.
Again, the advice is to use what some friends use, or what the local Linux group uses.
That way, you can ask questions.
For me, it is Xubuntu (after many years with Kubuntu). For others it is Mint.
The rest are not realistic options for a desktop (Debian, RedHat).


Dave Schwartz
 

On the STM32 Blue Pill PCB, microsteps for the axes are controlled by OnStep using the AXISn_MICROSTEPS and AXISn_MICROSTEPS_GOTO parameters. The jumpers on J1 and J2 as you have them now are only needed for the DRV8825 driver. Once you upgrade the drivers to LV8729's you do not need jumpers on J1 or J2.

On October 15, 2020 1:54:57 p.m. EDT, "Jochen.Siegfried@..." <jochen.siegfried@...> wrote:

Hi Khalid

this post answered my question according on how to connect a stepper motor to a stepper driver. Good !

 

But how to change Microsteps on a LV8729 Driver ?? Close to the driver there is one row with three pins. There is a jumer that can be moved.

I use STM32 blue pill, driver is LV8729 or at the moment DRV8825. For DVR8825, as it is now, the jumpers for both drivers are set to 3/2 and 2/3 means that the jumper connects pin 2 with pin3 for both drivers !

 

How do you set the jumper for 32 steps an the LV8729 ???

 

Thank you very much for your help !

Ferris

 

 

 

-----Original-Nachricht-----

Betreff: Re: [onstep] New set of goals for Losmandy- simplest solutions?

Datum: 2020-10-15T18:08:25+0200

Von: "Khalid Baheyeldin" <kbahey@...>

An: "main@onstep.groups.io" <main@onstep.groups.io>

 

 

 

On Thu, Oct 15, 2020 at 11:44 AM, W Maxwell wrote:
If I have a stock Losmandy GM8 and wish to replace the stock 492 and motors with something that can
1. move up to 32x via laptop control
2. Don't care about or need full GoTo
OnStep provides 32X and faster, so you get that if you replace the motors with steppers.
You also get Goto. It is up to you if you use it or not.
If tracking is all you need, you turn on autostart tracking, and forget about gotos.

3. Want the best tracking performance
OnStep is pretty much accurate. Tracking accuracy depends on many things.

4. Want it as close to prefab as humanly possible
Does not exist in OnStep, unless a member is willing to help you out with brackets
for mounting the motor, and puts together a board for you.

What do I get:
1. What board?
Depends if you will be putting it together yourself, or someone will help you with soldering
and such.

Even if you get the FYSETC S6 (full blown options including heaters, ...etc.) you still have
to wire things yourself (to the motors at a minimum).

2. What stepper drivers for the above choice?
These are the motors that are most proven to work with various OnStep mounts of GM8's size.

https://www.omc-stepperonline.com/nema-17-stepper-motor/Dual-Shaft-Nema-17-Bipolar-09deg-44Ncm-6248ozin-168A-28V-42x42x48mm-4-Wires.html

3. What motors with choice 1and 2?
There is no realistic option for "OnStep tracking only" or "none Goto OnStep".


--
Sent from my Android device with K-9 Mail. Please excuse my brevity.


professorburnout@...
 

I have used this company to supply drivers and motors when I was building CNC routers and mills. the customer service and prices have always been good.
I will getting motors and other hardware together for my GM8 project. I am getting a GM8 this weekend. 

https://www.automationtechnologiesinc.com/products-page/nema-17/kl17h248-20-4a


Khalid Baheyeldin
 

On Thu, Oct 15, 2020 at 04:01 PM, <professorburnout@...> wrote:
I have used this company to supply drivers and motors when I was building CNC routers and mills. the customer service and prices have always been good.
I will getting motors and other hardware together for my GM8 project. I am getting a GM8 this weekend. 

https://www.automationtechnologiesinc.com/products-page/nema-17/kl17h248-20-4a
Those motors are overkill.
They have a 2A rating, which is not needed for a mount of that size.
Even larger mounts (EQ6) do not need that kind of current.

Also, if you get them, you start limiting your choice of drivers, and boards.


professorburnout@...
 

Current is limited by the driver so torque would be less than specified. Looking at the specification page at each motor they are very similar but the main difference being the rated current of 2A vs 1.68A.

In our applications is this much of a difference? I will look for another thread to see if this is discussed in more detail. Instead of hijacking this topic.


Keep ups posted on the GM8 project. 

Paul


Jochen.Siegfried@t-online.de
 

Dave, Kalid ! Thank you for answering.

 

The motors I use are Nema17, 400steps, 0.9 Amps per phase. My power supply is 12V/5Amp. So I think Vref should be 0.45 amps ??? Is this correct !

 

So the Dec driver was not ajusted because RA was not heating up, although non of the motors was turning !

 

Can I adjust Vref with the drivers and all the other module still on the board ??

 

So, the OnStep App did nor connect to the board. Can I remove both motors and try again to connect to Onstep App ???? Can I split the problem. get the App to connect, then adjust Vref ???

 

I have no idea what this IP adress is all about !!

 

 

Khalid would you please explain. how to enter the Ip adress in the OnStep App ???

 

 

Sorry, for asking all these (stupid) questions ...

 

 

 

Thank you for all your help !
Ferris

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

-----Original-Nachricht-----

Betreff: Re: [onstep] New set of goals for Losmandy- simplest solutions?

Datum: 2020-10-15T21:11:53+0200

Von: "Dave Schwartz" <Dave.Schwartz@...>

An: "main@onstep.groups.io" <main@onstep.groups.io>

 

 

 

On the STM32 Blue Pill PCB, microsteps for the axes are controlled by OnStep using the AXISn_MICROSTEPS and AXISn_MICROSTEPS_GOTO parameters. The jumpers on J1 and J2 as you have them now are only needed for the DRV8825 driver. Once you upgrade the drivers to LV8729's you do not need jumpers on J1 or J2.

On October 15, 2020 1:54:57 p.m. EDT, "Jochen.Siegfried@..." <jochen.siegfried@...> wrote:

Hi Khalid

this post answered my question according on how to connect a stepper motor to a stepper driver. Good !

 

But how to change Microsteps on a LV8729 Driver ?? Close to the driver there is one row with three pins. There is a jumer that can be moved.

I use STM32 blue pill, driver is LV8729 or at the moment DRV8825. For DVR8825, as it is now, the jumpers for both drivers are set to 3/2 and 2/3 means that the jumper connects pin 2 with pin3 for both drivers !

 

How do you set the jumper for 32 steps an the LV8729 ???

 

Thank you very much for your help !

Ferris

 

 

 

-----Original-Nachricht-----

Betreff: Re: [onstep] New set of goals for Losmandy- simplest solutions?

Datum: 2020-10-15T18:08:25+0200

Von: "Khalid Baheyeldin" <kbahey@...>

An: "main@onstep.groups.io" <main@onstep.groups.io>

 

 

 

On Thu, Oct 15, 2020 at 11:44 AM, W Maxwell wrote:
If I have a stock Losmandy GM8 and wish to replace the stock 492 and motors with something that can
1. move up to 32x via laptop control
2. Don't care about or need full GoTo
OnStep provides 32X and faster, so you get that if you replace the motors with steppers.
You also get Goto. It is up to you if you use it or not.
If tracking is all you need, you turn on autostart tracking, and forget about gotos.

3. Want the best tracking performance
OnStep is pretty much accurate. Tracking accuracy depends on many things.

4. Want it as close to prefab as humanly possible
Does not exist in OnStep, unless a member is willing to help you out with brackets
for mounting the motor, and puts together a board for you.

What do I get:
1. What board?
Depends if you will be putting it together yourself, or someone will help you with soldering
and such.

Even if you get the FYSETC S6 (full blown options including heaters, ...etc.) you still have
to wire things yourself (to the motors at a minimum).

2. What stepper drivers for the above choice?
These are the motors that are most proven to work with various OnStep mounts of GM8's size.

https://www.omc-stepperonline.com/nema-17-stepper-motor/Dual-Shaft-Nema-17-Bipolar-09deg-44Ncm-6248ozin-168A-28V-42x42x48mm-4-Wires.html

3. What motors with choice 1and 2?
There is no realistic option for "OnStep tracking only" or "none Goto OnStep".

--
Sent from my Android device with K-9 Mail. Please excuse my brevity.



George Cushing
 

Max, I think you have dived in and need to get your breath. I think it may be a good idea to start with something simple. This MiniPCB:


can do pretty much all the 492 can and a bit more with you 492 hand controller. See:  https://onstep.groups.io/g/main/wiki/7150   About $35 in parts. Tuck it all in a small project box. This one was built for a Vixen GP owner that wanted to replace a dead DMD-2



Folks have used NEMA 14s with the GM-8, but finding 400 step in that size isn't easy and we're trying to keep this easy. So stick with a NEMA 17. I designed this motor bracket for the G11, but it fits the GM-8 also. Just 1/8" by 3" aluminum sheet. Tools needed: drill 5/32" bit, 7/8" hole saw and something to seat the bushing. The motor is limited to about 1.3" or 35mm in depth. 

If a small mill or CAD CAM router is available, an adjustable motor mounting makes fitting and tensioning a belt easier. However, with patience it can be done with a couple of files. This is my EQ-5 bracket. I generally use 40T:16T 2GT toothed pulleys and a 40mm belt for 3:1 reduction for the EQ-5. That's what I'd use for the GM-8 too.


Want to advance to goto it's $25 for the Smart Hand controller kit or add Bluetooth or Wifi to the MiniPCB and try a phone app. but at first just keep it simple.