AstroEQ Board

[malc-c]

1 hour ago, adyj1 said:

I fully appreciate the 'study the wiki until you are familiar with it' advice, but man, is it confusing!!! There are options on top of options on top of options! Some seem to have been good choices in the past but because the wiki is a collection of information over time it is difficult to tell exactly what is relevent now... 

Having said that, some of the comments on this thread have been very useful (and that photo!) and may well be enough to convince me to take the plunge. Knowing there is up-to-date advice available on the forum will be a big help. 

Thanks all! 

Ady

(apologies for the thread hijack, OP) 

 

It's on as complicated as you want it to be.  If you start with the basics, its an Adruinio UNO, and CNC shield with two stepper driver boards added (the wiki even stated the recommended ones "The LV8729 (or S109 for higher current motors) is the recommend driver due to its low cost and easy setup"

This will give you the basic equivalent of a motor board fitted in any SW goto telescope.  The clock / wifi / Bluetooth options are just that, options and not requirements.  If I was starting on this project I would simply follow the advice given here and get the recommended CNC shield, drives and UNO and then see how it works with the mount.  If I then want to add additional drives and stepper motors for the autofocus or other functionality  the code offers then I would look at doing that when I'm ready.  Start simple and then move up

[adyj1]

On 08/05/2021 at 19:04, lenscap said:

This is my Wemos R32, CNC V3 build before I put it in a case;

 

The lower board (that the power jack plugs into) is the R32.

The CNC (with all the yellow headers) just plugs into it. It only fits one way.

The two stepper drivers (with the blue heatsinks) plug into the CNC.

Just connect the  power &  the motors & you have a basic functional Onstep controller that can be directed by the Onstep app and/or Skysafari via Bluetooth or by Stellarium/CdC/Kstars etc by USB.

Would nema 14 0.8a steppers be any good for this? (guess what I already have 😉) 

Thanks

[lenscap]

1 hour ago, malc-c said:

If I was starting on this project I would simply follow the advice given here and get the recommended CNC shield, drives and UNO

Thanks Malcolm,

To clarify one point, the WeMos D1 R32 has exactly the same footprint as the Arduino UNO, but the UNO is not used here because it has insufficient memory to run OnStep.

[malc-c]

1 hour ago, adyj1 said:

Would nema 14 0.8a steppers be any good for this? (guess what I already have 😉) 

Thanks

Read the wiki and then check the data sheet for the motors..

wiki  and datasheet

10 minutes ago, lenscap said:

Thanks Malcolm,

To clarify one point, the WeMos D1 R32 has exactly the same footprint as the Arduino UNO, but the UNO is not used here because it has insufficient memory to run OnStep.

to quote the wiki

If it's not able to run the software then why include the statement below... no wonder why people find it confusing !

Quote

The image below shows a Arduino UNO with CNC V3 Shield.  Similar to a MaxPCB2/MaxESP3, this design offers a good balance of features and performance including the ability to operate the mount and two focusers or a focuser and rotator.  It also does this for low cost and with little need for soldering.

 

Edited May 10, 2021 by malc-c

[astrosathya]

Keep it coming guys,

I absolutely love it when there's a lively discussion happeneing.

36 minutes ago, malc-c said:

Read the wiki and then check the data sheet for the motors..

wiki  and datasheet

to quote the wiki

If it's not able to run the software then why include the statement below... no wonder why people find it confusing !

 

i checked the datasheet, obviously I have teh exact same motor. I am guessing the connectors also have the 0.1" pitch between the pins. I have ordered the drivers, i just need to wait for them to be delivered and off i shall go. While I can easily design a box for the controller using Fusion 360, if theres one already available, i'd be happy to use it

[malc-c]

1 hour ago, astrosathya said:

Keep it coming guys,

I absolutely love it when there's a lively discussion happeneing.

i checked the datasheet, obviously I have teh exact same motor. I am guessing the connectors also have the 0.1" pitch between the pins. I have ordered the drivers, i just need to wait for them to be delivered and off i shall go. While I can easily design a box for the controller using Fusion 360, if theres one already available, i'd be happy to use it

I wasn't suggesting you compare the data sheet with the motors you have, I was suggesting you compare it to the stepper drivers specifications you are intending to use, and the requirements of the projects abilities.  I personally don't think there would be an issue as (AFAIK) most SW mounts use NEMA 17s.  But sometimes manufactures may change things like microsteps etc which could lead to the mount tracking at the wrong rate as the software can not account for this.  I've never built one so can't really advise, so hopefully one of the others can chime in and confirm if your motors are OK. 

But I thought you had an HEQ5 and will be using that, and AFAIK the HEQ5s use NEMA 17's 

[astrosathya]

1 hour ago, malc-c said:

I wasn't suggesting you compare the data sheet with the motors you have, I was suggesting you compare it to the stepper drivers specifications you are intending to use, and the requirements of the projects abilities.  I personally don't think there would be an issue as (AFAIK) most SW mounts use NEMA 17s.  But sometimes manufactures may change things like microsteps etc which could lead to the mount tracking at the wrong rate as the software can not account for this.  I've never built one so can't really advise, so hopefully one of the others can chime in and confirm if your motors are OK. 

But I thought you had an HEQ5 and will be using that, and AFAIK the HEQ5s use NEMA 17's 

Malcolm,

My HEQ5-PRO is from 2012. I can assure you the dimensions are 35mmX35mmX34-37ish mm as measured using a ruler corresponding to a Nema14HS13 as I found independently online. as teh L max is 35-37mm ish for the HS13 . I have a Nema 17 which i used for the MyFocuserPro2 and thats much bigger and wont fit into the space inside the mount.

Regarding the drivers, I now have 2 different sets, the DRV8825's and the A4988's, so i will have choice on which to use as both will work.

Edited May 10, 2021 by astrosathya

[malc-c]

I stand corrected

 

 

Edited May 10, 2021 by malc-c

[astrosathya]

All the parts i've ordered from various vendors are in different stages of shipment. I will hopefully have everything in hand within a week. Till then i can only read up on the work of others and obsess and imagine etc, maybe design a 3D printable case. I calculated the config parameters for the config generator. 

[lenscap]

20 hours ago, astrosathya said:

Regarding the drivers, I now have 2 different sets, the DRV8825's and the A4988's, so i will have choice on which to use as both will work.

Your Config looks good except for the microsteps. The DRV8825's are limited to 32, and the A4988's to 16.

For 64 microsteps you will need the LV8729 drivers.

[astrosathya]

3 hours ago, lenscap said:

Your Config looks good except for the microsteps. The DRV8825's are limited to 32, and the A4988's to 16.

For 64 microsteps you will need the LV8729 drivers.

Yes, I have cancelled the order for the a4988's and instead ordered LV8729's because of the 1/64 requirement. All parts are on their way from different suppliers. Sourcing has become a major issue due to the prevailing lockdown in our city. 😕

[lenscap]

 

Hi @malc-c,

I posted a question about whether or not OnStep will run on the UNO,  on the OnStep forum and here is the reply from one of the developers;

Just completed my second OnStep (WeMos D1 R32/CNC V3) when a colleague pointed out that according to this section of the Wiki;   https://onstep.groups.io/g/main/wiki/19670 , OnStep will run, albeit with limited features, on an Arduino UNO with CNC V3 shield. I'm sure I've read somewhere that it won't. So my question is (just out of interest) will Onstep run on an UNO or not? Thanks for all the great work.

Reply  Like  More

Khalid Baheyeldin May 10   #33543     No, the Arduino UNO will not run OnStep. That page should be reworded to remove any reference to the UNO. In the Arduino family, only the Mega2560 will run OnStep because it has the required 256K flash storage to hold the OnStep program image. Even the Mega2560 is the slowest of the boards that run OnStep, and suffers from an inaccurate clock, which needs to be mitigated with an RTC. You are better off with the R32 which has a much faster microcontroller.

[malc-c]

Well that clears that up....

I was googling the spec of these Wemos D1R3 boards...  Interesting that these boards have a processor running at 240Mhz...and that the flash is 4 MB.... which seems a lot, especially when you think that most of the SW motorboards use 16F886 Microcontrollers running at 20mHz.... and its memory is in KB rather then MB !!

 

[skybadger]

I think you are asking a lot from those steppers to drive much at 1/32 step or more.  I ran mine at 24v for a while to see if they could get past the base stiction and get up to to speedbut you can of course start coarse and go fine later by simple reprogramming. 

 

[astrosathya]

14 hours ago, lenscap said:

 

Hi @malc-c,

I posted a question about whether or not OnStep will run on the UNO,  on the OnStep forum and here is the reply from one of the developers;

Just completed my second OnStep (WeMos D1 R32/CNC V3) when a colleague pointed out that according to this section of the Wiki;   https://onstep.groups.io/g/main/wiki/19670 , OnStep will run, albeit with limited features, on an Arduino UNO with CNC V3 shield. I'm sure I've read somewhere that it won't. So my question is (just out of interest) will Onstep run on an UNO or not? Thanks for all the great work.

Reply  Like  More

Khalid Baheyeldin May 10   #33543     No, the Arduino UNO will not run OnStep. That page should be reworded to remove any reference to the UNO. In the Arduino family, only the Mega2560 will run OnStep because it has the required 256K flash storage to hold the OnStep program image. Even the Mega2560 is the slowest of the boards that run OnStep, and suffers from an inaccurate clock, which needs to be mitigated with an RTC. You are better off with the R32 which has a much faster microcontroller.

yes, i read your post and the replies.  The boards are arriving today (yaaaaaaayyyy :P) Other components are yet to arrive.

[astrosathya]

Few of the components have arrived

 

 

[astrosathya]

Some more progress. After finding a few arduino UNO CNCV3 cases on Thingiverse, i realised "what if it doesn't fit"?. I then found a 3D model of Wemos D1 R32 on grabcad which i used as a refernce to design a case. Now the idea is to of course stack the CNCV3 on the Wemos + the heatsinks for the drivers. After a quick measurement, i found the height to be 47mm and to be on the safe side i put in the designed height as 52mm, enough for any errors. The ports were projected to a new construction plane and given a positive offset of about 1mm as wiggle space. Below are a few screenshots of the case. It will have a simple text on it. If anyone has SVG files for the LOGO of OnStep, please do share, i'd be grateful. I have ordered the 3D print.

[John78]

On 11/05/2021 at 18:31, skybadger said:

I think you are asking a lot from those steppers to drive much at 1/32 step or more.  I ran mine at 24v for a while to see if they could get past the base stiction and get up to to speedbut you can of course start coarse and go fine later by simple reprogramming. 

 

The trinamic drivers in either drive mode stealthchop (silent) or spreadcycle deliver more torque than a conventional driver in half step mode, and spreadcycle 256usteps delivers only slightly less torque than full stepping, they're amazing pieces of tech, the issue used to be generating the clocks to accelerate and run them at high rpm in 256usteps, but with modern processors that's not an issue, no way could an arduino do it.

 

Thanks to OP and repliers for highlighting onstep - have ordered some MaxSTM boards from JLCPCB today to change from astroeq (which has a really frustrating windows bug) to an OnStep controller.  The ascom info required seems to all on this site.

 

edit: let me rephrase that, windows has a really frustrating bug, that requires the astroeq to be powered before you plug in the usb - it works fine in linux as it handles the ports properly.

 

http://www.stellarjourney.com/index.php?r=site/software_telescope

 

Edited May 13, 2021 by John78

[skybadger]

8 hours ago, John78 said:

The trinamic drivers in either drive mode stealthchop (silent) or spreadcycle deliver more torque than a conventional driver in half step mode, and spreadcycle 256usteps delivers only slightly less torque than full stepping, they're amazing pieces of tech, the issue used to be generating the clocks to accelerate and run them at high rpm in 256usteps, but with modern processors that's not an issue, no way could an arduino do it.

 

Thanks to OP and repliers for highlighting onstep - have ordered some MaxSTM boards from JLCPCB today to change from astroeq (which has a really frustrating windows bug) to an OnStep controller.  The ascom info required seems to all on this site.

 

edit: let me rephrase that, windows has a really frustrating bug, that requires the astroeq to be powered before you plug in the usb - it works fine in linux as it handles the ports properly.

 

http://www.stellarjourney.com/index.php?r=site/software_telescope

 

That may be true and is the way mine is setup but the OP was not planning to use the tmcxxxx drivers due to them needing the spi bus wiring up. 

 

 

 

 

 

 

 

 

Edited May 14, 2021 by skybadger

[astrosathya]

8 hours ago, John78 said:

The trinamic drivers in either drive mode stealthchop (silent) or spreadcycle deliver more torque than a conventional driver in half step mode, and spreadcycle 256usteps delivers only slightly less torque than full stepping, they're amazing pieces of tech, the issue used to be generating the clocks to accelerate and run them at high rpm in 256usteps, but with modern processors that's not an issue, no way could an arduino do it.

 

Thanks to OP and repliers for highlighting onstep - have ordered some MaxSTM boards from JLCPCB today to change from astroeq (which has a really frustrating windows bug) to an OnStep controller.  The ascom info required seems to all on this site.

 

edit: let me rephrase that, windows has a really frustrating bug, that requires the astroeq to be powered before you plug in the usb - it works fine in linux as it handles the ports properly.

 

http://www.stellarjourney.com/index.php?r=site/software_telescope

 

initially i was not really sure about the opensource boards and only because a friend uses AstroEQ, i gravitated to it but soon found that they give little to no support on their forum. I then looked at the OnStep Wiki. 10 minutes later, i got hooked. Now there's no turning back.  We need to highlight such work because there are many folks out there who'd like a nice goto mount but cannot affor paying $$$$. OnStep is an amazing, economic and vastly superior tech compared to the boards supplied with commercial brands like SW etc.

[astrosathya]

9 minutes ago, skybadger said:

That may be true and is the way mine is setup but the OP was not planning to use the tmcxxxx drivers due to them needing the spi bus wiring up. 

 

 

 

 

 

 

 

 

looks like if i need to use my 8729 drivers i need to wire up M0 and M2 on the CNCV3? or am i getting it wrong?

[John78]

On 14/05/2021 at 06:53, astrosathya said:

looks like if i need to use my 8729 drivers i need to wire up M0 and M2 on the CNCV3? or am i getting it wrong?

Never used 8729, but this guy has a build log of exactly what you are using...

ONSTEP EQ5 GOTO (groups.io)

Your gear ratios will be different, the AstroEQ site has all the appropriate gear ratios for the SW mounts.

[lenscap]

On 14/05/2021 at 06:53, astrosathya said:

looks like if i need to use my 8729 drivers i need to wire up M0 and M2 on the CNCV3? or am i getting it wrong?

Hi Sathya,

The LV8729 data sheet includes the microstepping table; https://wiki.fysetc.com/LV8729_V1.0/

For 64 microsteps you need to hold the ms2 and ms3 pins high on each driver. [ Just to cause confusion the CNC uses  different terminology (m0, m1,m2 instead of ms1,ms2,ms3). ]  To achieve this all you need to do is shunt the m1 & m2 pairs under each driver with something like these; 2-54mm-0-1-PCB-Header-Jumper-Link

As said above you don't need to wire anything to the SPI bus since you are using LV8729's.

Edited May 17, 2021 by lenscap
punctuation

[astrosathya]

More progress guys

I uploaded the firmware and had a test drive, without the cncv3 and motor connected. The test can be seen in this video.

C&C always welcome.

[chemistorge]

Not sure if this is of help but I have designed a shield for the mega so that the AstroEq mega build is very simple. I have published full docs and Gerber files here: