×
INDI Library v1.8.5 Released (19 Apr 2020)

April 2020 release of INDI Library v1.8.5 introduces new drivers while providing fixes and improvements to existing devices and core framework.

INDI focuser driver for Waveshare Stepper Motor HAT for Raspberry Pi

1 month 1 week ago
kross
Expert Boarder
Expert Boarder
Posts: 123
Karma: 2
More
Topic Author
INDI focuser driver for Waveshare Stepper Motor HAT for Raspberry Pi #54521

esb wrote: And a problem like this wouldn't be complete without a facepalm. I just noticed with the stepper attached to my RedCat, if I ran it from 0 (fully retracted) to nearly max (500) and then back to 0, it kept missing the zero point by a few degrees (it was always short). It turns out the grub/set screw for the pulley attached to the stepper is loose. Double-d'oh! That means I have at least 10+ steps of backlash. I'm guessing it will work much better with a tight pulley.


Consider yourself getting off easy! When I did the Rowan belt mod for my Orion Atlas mount, one of the set screws on a pully deep inside the mount wasn't tight enough. Took me a month to figure out why I was getting such bad backlash in Dec movements! So I had to tear the mount apart to tighten that screw. I put blue Loc-Tite on those screws, just because I was mad at them!

Please Log in or Create an account to join the conversation.

1 month 1 week ago
esb
Senior Boarder
Senior Boarder
Posts: 54
More
INDI focuser driver for Waveshare Stepper Motor HAT for Raspberry Pi #54522
With my existing stepper, backlash now seems to be around 1 step. I can see clear consistent movement for even a single step and when changing directions at most that first step doesn't show full movement. I can see that with large moves in one direction followed by single step moves in the other. When does darkness get here? I really can't way to try it out again.

Please Log in or Create an account to join the conversation.

1 month 1 week ago
esb
Senior Boarder
Senior Boarder
Posts: 54
More
INDI focuser driver for Waveshare Stepper Motor HAT for Raspberry Pi #54523

kross wrote:

esb wrote: And a problem like this wouldn't be complete without a facepalm. I just noticed with the stepper attached to my RedCat, if I ran it from 0 (fully retracted) to nearly max (500) and then back to 0, it kept missing the zero point by a few degrees (it was always short). It turns out the grub/set screw for the pulley attached to the stepper is loose. Double-d'oh! That means I have at least 10+ steps of backlash. I'm guessing it will work much better with a tight pulley.


Consider yourself getting off easy! When I did the Rowan belt mod for my Orion Atlas mount, one of the set screws on a pully deep inside the mount wasn't tight enough. Took me a month to figure out why I was getting such bad backlash in Dec movements! So I had to tear the mount apart to tighten that screw. I put blue Loc-Tite on those screws, just because I was mad at them!


Its especially ironic because the grub screw is one of the first things I advise others to check for many different kinds of 3d printer issues. I need to take my own advice.

Please Log in or Create an account to join the conversation.

1 month 1 week ago
El Corazon
Platinum Boarder
Platinum Boarder
Posts: 765
Karma: 3
More
INDI focuser driver for Waveshare Stepper Motor HAT for Raspberry Pi #54524

esb wrote:

kross wrote:

esb wrote: And a problem like this wouldn't be complete without a facepalm. I just noticed with the stepper attached to my RedCat, if I ran it from 0 (fully retracted) to nearly max (500) and then back to 0, it kept missing the zero point by a few degrees (it was always short). It turns out the grub/set screw for the pulley attached to the stepper is loose. Double-d'oh! That means I have at least 10+ steps of backlash. I'm guessing it will work much better with a tight pulley.


Consider yourself getting off easy! When I did the Rowan belt mod for my Orion Atlas mount, one of the set screws on a pully deep inside the mount wasn't tight enough. Took me a month to figure out why I was getting such bad backlash in Dec movements! So I had to tear the mount apart to tighten that screw. I put blue Loc-Tite on those screws, just because I was mad at them!


Its especially ironic because the grub screw is one of the first things I advise others to check for many different kinds of 3d printer issues. I need to take my own advice.


I still want to go head-to-head with your design.

Identical optical train, so it's just the focuser.

We got to have a competition, Eric!!!

:-)

Best, Jo

Atlas Pro AZ-EQ, ASI1600MM-Pro, ASI120MM-S, ES102ED, WO-Z61, Nikon D3300, ASI-EFW, ZWO LRGB,Ha,O3,S2 filter set

Please Log in or Create an account to join the conversation.

1 month 1 week ago 1 month 1 week ago by elken2004.
elken2004
Fresh Boarder
Fresh Boarder
Posts: 13
More
INDI focuser driver for Waveshare Stepper Motor HAT for Raspberry Pi #54525
I win, been there done that :) I hate Helical's
Attachments:

Please Log in or Create an account to join the conversation.

1 month 1 week ago
El Corazon
Platinum Boarder
Platinum Boarder
Posts: 765
Karma: 3
More
INDI focuser driver for Waveshare Stepper Motor HAT for Raspberry Pi #54526
That is cool! The key is the tension pulley. That makes all the difference for eliminating backlash, I bet.
Alright, you can be part of the Olympiad here.
I am not chickening out. I am still confident I will win.
:-)
Jo

Atlas Pro AZ-EQ, ASI1600MM-Pro, ASI120MM-S, ES102ED, WO-Z61, Nikon D3300, ASI-EFW, ZWO LRGB,Ha,O3,S2 filter set

Please Log in or Create an account to join the conversation.

1 month 1 week ago 1 month 1 week ago by elken2004.
elken2004
Fresh Boarder
Fresh Boarder
Posts: 13
More
INDI focuser driver for Waveshare Stepper Motor HAT for Raspberry Pi #54527
Already tested, and it worked a treat, the last pic is of Rho, having used full autofocusing
Attachments:

Please Log in or Create an account to join the conversation.

1 month 1 week ago
kross
Expert Boarder
Expert Boarder
Posts: 123
Karma: 2
More
Topic Author
INDI focuser driver for Waveshare Stepper Motor HAT for Raspberry Pi #54528
Very nice! Just curious, what are using to control the stepper motor? The Waveshare HAT, or some other (possibly Arduino) controller?

Please Log in or Create an account to join the conversation.

1 month 1 week ago 1 month 1 week ago by El Corazon.
El Corazon
Platinum Boarder
Platinum Boarder
Posts: 765
Karma: 3
More
INDI focuser driver for Waveshare Stepper Motor HAT for Raspberry Pi #54532

elken2004 wrote: Already tested, and it worked a treat, the last pic is of Rho, having used full autofocusing


Yes, very nice! I think as far as accurate focus is concerned, this may come to a draw. This is what I got from the middle of a large metro area (Dallas), Bortle 8/9, and with an inferior mount (iOptron SmartEQPro+; RMS 4+, 7 arcsec/pixel).



Not nearly as nice as yours, editing not yet completed, needs more narrowband, but this is about focusing. The focusing routine (linear, automated and repeated hourly through the night) was posted earlier in this thread.

Atlas Pro AZ-EQ, ASI1600MM-Pro, ASI120MM-S, ES102ED, WO-Z61, Nikon D3300, ASI-EFW, ZWO LRGB,Ha,O3,S2 filter set
Attachments:

Please Log in or Create an account to join the conversation.

1 month 1 week ago
esb
Senior Boarder
Senior Boarder
Posts: 54
More
INDI focuser driver for Waveshare Stepper Motor HAT for Raspberry Pi #54558
The focused worked much better last night. I now get the expected V / curve during auto focus. I could repeatably move focus away from the focus point and back to the same step number and things were in sharp focus. I still need to tune the parameters for the auto focus algorithm itself. It was never able get it to automatically choose the focus point (though I was able to choose it myself based on the data from the auto focus process). I’m using the linear focus algorithm. Once it finishes the first pass, it then appears to try to take multiple readings at the same steps right around the focus point. However my seeing must be varying enough that it couldn’t get consistent enough readings without moving the focuser and would eventually error out. I adjusted the tolerance % without success, though I’m not sure that’s the right parameter. I didn’t spend a lot of time as I wanted to get started imaging, so I just chose the best focus point and moved on.

Please Log in or Create an account to join the conversation.

1 month 1 week ago
kross
Expert Boarder
Expert Boarder
Posts: 123
Karma: 2
More
Topic Author
INDI focuser driver for Waveshare Stepper Motor HAT for Raspberry Pi #54565
Congrats on the progress! :)

For myself, auto selecting a single focus point has never been reliable. I either need to manually select a single point, or use full field mode. Full field mode is the method I use now. You can even tell it to limit itself to the central part of the image, if you prefer.

I use the polynomial focus method. It seems to work well enough. I never tried the linear. I might give that a try. Some people say it works better.

Please Log in or Create an account to join the conversation.

1 month 1 week ago
El Corazon
Platinum Boarder
Platinum Boarder
Posts: 765
Karma: 3
More
INDI focuser driver for Waveshare Stepper Motor HAT for Raspberry Pi #54566

kross wrote: Congrats on the progress! :)

For myself, auto selecting a single focus point has never been reliable. I either need to manually select a single point, or use full field mode. Full field mode is the method I use now. You can even tell it to limit itself to the central part of the image, if you prefer.

I use the polynomial focus method. It seems to work well enough. I never tried the linear. I might give that a try. Some people say it works better.



I have always used Full Field mode. Set tolerance to 5%. Much depends on the initial step size with the linear focuser. If that is too large, it may miss the minimum. But once established for a specific focuser and telescope, it will hit the optimal focus every time.

If you have NO backlash, polynomial may be better, because step size will continuously decrease while converging upon the minimum. But if there is ANY backlash in your system, linear will be more consistent and reliable IME.

Atlas Pro AZ-EQ, ASI1600MM-Pro, ASI120MM-S, ES102ED, WO-Z61, Nikon D3300, ASI-EFW, ZWO LRGB,Ha,O3,S2 filter set

Please Log in or Create an account to join the conversation.

Time to create page: 1.408 seconds