Cheap EQ Goto SimpleDream Onstep

[Gmx76]

29 minutes ago, lenscap said:

Welcome back.

I suggest you post this query on the Onstep forum. https://onstep.groups.io/g/main/topics

One of the developers will usually respond in about 24 hours. Summarise your build hardware & specify exactly which ESP32 board & version number you are selecting in the Arduino board manager.

Great will do thanks

[lenscap]

In the Arduino IDE, can you confirm that you have the correct version of the correct board software installed.

The board you need is the "ESP Dev Module" and you must use version "1.0.4"

In the IDE click "Tools" and you should see,  board "ESP Dev Module"

If so highlight it, click "Boards Manager" & scroll down to" ESP32" it should be "version 1.0.4", if not  click "version" and select and install version 1.0.4.

I don't know if this solves your problem but worth a check.

[Gmx76]

just thought I'd share my excitement that I actually have spinning motors when I try a GoTo from the Android app!!

Stil got work to do but getting progress

[Gmx76]

On 03/08/2021 at 16:32, lenscap said:

Once you have mounted the motors & pulleys you can measure the shaft spacings and calculate the  belt lengths.

Hi @lenscap motors and pulleys mounted! When measuring the shaft spacings,  do you measure centre to centre, or from the outside edge? Thanks!

[lenscap]

You need the centre to centre shaft spacing & the Pitch Diameters of the two pulleys.

Dimensions of GT2 pulleys (which have 2mm tooth pitch) can be downloaded from here;  https://www.pfeiferindustries.com/timing-belt-pulley-pitch-diameter-outside-diameter-charts

The belt length = ( 2 x shaft spacing ) + Pi ( (PD1 +PD2)/2 )

Say you calculate about 149mm you will need a 150mm, 75 tooth belt.

Edit;  @Gmx76 the above formula is approximate.

There is a more accurate calculator here; https://www.omnicalculator.com/physics/belt-length

Edited October 2, 2021 by lenscap

[Gmx76]

On 14/07/2021 at 18:11, lenscap said:

The two stepper drivers, (I used LV8729's, with the blue heatsinks) plug into the CNC V3 without the need for any wiring.

Hi @lenscap motors are driving the mount! Hope to do a proper test today or tomorrow. What did you use to cover the stepper motor wires?

[lenscap]

1 hour ago, Gmx76 said:

What did you use to cover the stepper motor wires?

I used 6mm spiral wrap like this.   https://www.ebay.co.uk/itm/160956288816?hash=item2579be0f30:g:eEoAAOxyuR5TYLhD

When setting time etc note that the time zone (GMT offset in Onstep-speak) is zero in the British Isles,  all year round, even when we are on BST. That caught me out.

Bet you can't wait to get it pointed at some stars!

[Gmx76]

I can't actually believe I got this far...

Spiral wrap on order. Tested tonight but goto not working right.  Tried Caph in Cassiopeia to the NE. Telescope moves WNW parallel to the ground.

Tried Jupiter South West, mount turns North East and pointing towards the ground.

Any ideas? Will try onstep forum too.

thanks

[lenscap]

12 hours ago, Gmx76 said:

Tested tonight but goto not working right.  Tried Caph in Cassiopeia to the NE. Telescope moves WNW parallel to the ground.

Tried Jupiter South West, mount turns North East and pointing towards the ground.

I assume you are controlling the mount with the Android app.

You must tap "Initiallize/Park" and then "Set Time" each time you power up the controller or it will remember the time from the last session & probably be way out .

Check your location lat/long.( If it is correct you don't have to enter it every time, it remembers last location.)

Select your first alignment star, loosen the clutches and manually point the scope at the  star,  then tighten the clutches and  press  & confirm Align. Now select & attempt to Goto a second alignment star & note whether the RA and Dec move in the correct directions. If necessary reverse either or both motor directions. (just rotate the relevant 4-pin connector through 180 degrees  to reverse a motor.)

HTH

 

[Gmx76]

hi yes I am using the app. ok when the clouds clear will give it a go, cheers

[Gmx76]

Progress! Flipped the cables and things a whole lot better.  Goto seemed to work as best I could tell given I was trying to align on what seemed to be moving targets among the cloud cover.  Need a clear night for a proper test. 

Edited October 14, 2021 by Gmx76
Typo

[Gmx76]

Well after over 3 months of reading,  buying bits from various places,  waiting,  getting confused, getting help,  jumping in and putting it altogether (plus a bout of covid to contend with) I am finally calling this project a success!

Goto's and tracking working from the app!!

It's been a ride but HUUUGE thanks to @lenscapfor starting me off on this journey and your support along the way,  and @fozzybear for extra guidance and linking me to that hugely useful guide from Oddvar Naess. 

There were a few issues a long the way,  which i resolved with help or figured out myself,  and when I'm feeling a little better from covid I'll do a full write-up. 

But I have achieved my aim of building a cheap goto system for my eq3 and learnt a ton of things along the way.  

On(step)wards and upwards!

[fozzybear]

13 minutes ago, Gmx76 said:

Well after over 3 months of reading,  buying bits from various places,  waiting,  getting confused, getting help,  jumping in and putting it altogether (plus a bout of covid to contend with) I am finally calling this project a success!

Goto's and tracking working from the app!!

It's been a ride but HUUUGE thanks to @lenscapfor starting me off on this journey and your support along the way,  and @fozzybear for extra guidance and linking me to that hugely useful guide from Oddvar Naess. 

There were a few issues a long the way,  which i resolved with help or figured out myself,  and when I'm feeling a little better from covid I'll do a full write-up. 

But I have achieved my aim of building a cheap goto system for my eq3 and learnt a ton of things along the way.  

On(step)wards and upwards!

Greg,

Glad you are on your way 

Andy

[Gmx76]

Cheers Andy!

[fozzybear]

I've currenty got an astroeq setup on my EQ5 but wanted to try the onstep route with a wemos and shield v3 with LV8729's  just for fun

[Gmx76]

Now I've done it once I would do it again. Might upgrade to an eq5 at some point,  so will either port this Onstep or build a new one. 

 

[lenscap]

4 hours ago, Gmx76 said:

Might upgrade to an eq5 at some point,  so will either port this Onstep or build a new one.

I temporarily fitted my original Mega/Ramps Onstep to a new (to me) EQ5 while building the Wemos/CNC version for it. Just needed to reconfig the software and fit new drive belts because the shaft spacings are different to the EQ3-2. Mechanically the EQ5 build is actually easier because the RA motor can be mounted on a single off-the -shelf angle bracket just like the Dec.

Now the Mega/Ramps Onstep is back on the EQ3-2 which I now use for visual, having converted the mount, and configured the Onstep software to Alt/Az.

You can't do any of that with the Synscan upgrade kits, which are now about £380 !!!

Congrats on your build.

Edited October 22, 2021 by lenscap

[Gmx76]

So much cheaper and more flexible than an out the box solution.  Cheers again @lenscap!

[Coco]

Blimey guys I'm itching to have a go.. DIY Alt Az mount would be my first choice as I have large 90degree binoculars on back order

Well done for giving it a go Greg!

[dazzystar]

Hi All,

Thought I'd join the convo and ask a question. I want to replace the crappy motors on my EQ3 Pro goto mount with steppers and have just discovered the OnStep project. As my use is remote imaging I don't want to use a hand controller but control the equipment via ASCOM and NINA. Has anyone modded their EQ3 Pro and could you provide a list of parts / bits needed so I can look into it in more detail please?

Cheers

Daz

[Gmx76]

hi, if you look back at first couple of pages, @lenscap details out the parts needed, and I took his recommendations.  I used NEMA17 400 steps, https://amberspyglass.co.uk/store/48mm-nema17-stepper-motor-400step-per-rev.html. Brought from these guys. ASCOM is supported by this project, so you would need to connect it to a windows device.

Just be aware this is not plug n play as such, do plenty of research and ask lots of questions!

[dazzystar]

Thanks for the reply. I'm in the process of building a DIY autofocuser based on a Nema 17 PG5 and Arduino Nano so am used to asking lots (and lots) of questions!

I've joined the onstep group but cannot fathom how to begin to ask questions. It's not like our forum software here is it!

[dazzystar]

I should have asked how accurate is the OnStep mod in comparison to the original motors?

[Gmx76]

no idea as haven't tried myself

[lenscap]

2 hours ago, dazzystar said:

I want to replace the crappy motors on my EQ3 Pro goto mount with steppers

Hi Daz, I'm a big fan of Onstep - it is much more flexible & configurable than Synscan -  , but before you go ahead is your Synscan Goto in full working order and what shortcomings are you expecting to eliminate?

The motors may look crappy compared to NEMA17's 😀 but they are steppers and can drive the mount at 800x siderial.

1 hour ago, dazzystar said:

I should have asked how accurate is the OnStep mod in comparison to the original motors?

You can chose motors, pulleys & microstep settings to give the same ( or slightly better ) theoretical accuracy as Synscan but in practice both systems rely on the mechanical accuracy of the mount and the EQ3-2 is not a piece of precision engineering. Belt drives will be more accurate ( and much quieter and probably require less tinkering ) than spur gears but in either case you will need to minimise the backlash in the worm drives by mechanical adjustment and carry out precise star alignments to get accurate Goto's.

I think that the greatest strength of Onstep is that you can convert a manual mount to a full Goto system for maybe a third of the cost of the Synscan upgrade kit. Since you already have a Synscan Pro I wonder if you would be spending a lot of time and effort with no guarantee of significant improvement.

If you go ahead the Onstep Wiki will answer most of your questions;   onstep@groups.io | Wiki

Good luck.