Go Back   IceInSpace > Equipment > ATM and DIY Projects

Reply
 
Thread Tools Rate Thread
  #1  
Old 23-12-2015, 04:43 PM
elken2004 (Australia)
Registered User

elken2004 is offline
 
Join Date: Jan 2015
Location: boronia
Posts: 35
Elkens diy focuser using arduino nano

Thought I might share this project

It took about three weeks to come to terms with working with Arduino gear and its software etc what an adventure. but all good in the end.

then the mechanics presented its own big challenge too.

items were
Arduino nano
Drv8825 stepper power module
Keys encoder module (better than using a two button setup
gives you the ability to to click for different speeds and a dial up feature, as in back and forth with focuser.

Lcd 1602 12c LCD panel
some vero pcb/headers/

I ended up with about 6 microns per full step, and go down to 1/32 steps.

The final pic shows the stepper in a box which was simply screwed to the stepper itself, with a cutout in the lid for cable and belt.

I could not get the direct to the shaft working reliably so after much work it uses the 10:1 knob which has a 5mm hole drilled from outside, and threaded to take a bolt which holds the gear.
There is no load pressure on the 10:1 shaft itself as the belt is not overly tight, it does not need to be ( that shaft is only 2mm thick too )

I now cant wait to test the 6" refractor with my ST8xe, using the ascom driver and MaximDL I can now do focus offsets.
No more blue bloom, or should i say out of focus.
when I can get time I will learn to use focus max for auto focusing..

I had done some test shots the other using the 80mm and my 60d, I got better
shots than ever before.

I should add that it is fully ascom compliant and has a stand alone window driver, as well as being fully stand alone without any computer. by just using the dial encoder for single stepping or dial up different speeds etc.
The adventure continues........
Attached Thumbnails
Click for full-size image (IMG_5822 (Medium).jpg)
117.4 KB91 views
Click for full-size image (IMG_5825 (Medium).JPG)
97.5 KB86 views
Click for full-size image (IMG_5826 (Medium).JPG)
147.5 KB87 views
Click for full-size image (IMG_5828.JPG)
71.4 KB76 views
Click for full-size image (IMG_5829.JPG)
92.4 KB71 views
Click for full-size image (IMG_5840.JPG)
112.7 KB76 views

Last edited by elken2004; 23-12-2015 at 06:00 PM.
Reply With Quote
  #2  
Old 24-12-2015, 07:37 AM
LightningNZ's Avatar
LightningNZ (Cam)
Registered User

LightningNZ is offline
 
Join Date: Oct 2011
Location: Canberra
Posts: 952
Great work! I'm being given a book on building Arduino projects for Christmas and I'm super excited to do stuff like this.
Cheers,
Cam
Reply With Quote
  #3  
Old 01-01-2016, 12:02 PM
brown_rb (Robert)
Registered User

brown_rb is offline
 
Join Date: Aug 2010
Location: Wellington, NZ
Posts: 8
Is that the myFocuser DIY project on Sourceforge?
Reply With Quote
  #4  
Old 01-01-2016, 12:18 PM
elken2004 (Australia)
Registered User

elken2004 is offline
 
Join Date: Jan 2015
Location: boronia
Posts: 35
Reply

Hi Rob,
It certainly is.

In Mallacoota ATM.

Wishing I had built a version for my Canon, the skies are quite dark here.

Can you drop the links to the project here.

I am very pleased with the results so far.
Reply With Quote
  #5  
Old 01-01-2016, 03:27 PM
codemonkey's Avatar
codemonkey (Lee)
Lee "Wormsy" Borsboom

codemonkey is offline
 
Join Date: Jul 2013
Location: Kilcoy, QLD
Posts: 2,049
Awesome work mate! I think I've finished up on mine now, it's not as easy as I'd have thought to be honest. My guess is you were probably unable to get enough torque with direct drive on the main shaft.

I ended up going with a geared motor (26.8:1) running at < 0.75a directly onto my main shaft in order to get enough torque whilst full stepping.

Interestingly enough I was having an issue with dropped steps, even when running quite slow, until I turned the pot down on the driver board (max at 0.75ma, turned it down about 20% and suddenly no more skipped steps!).

Anyway, it's a fun project and it looks like you've done a great job on yours... better than the "jam it all into a sistema tub and bolt it on" job that I did that's for sure!
Reply With Quote
  #6  
Old 02-01-2016, 07:06 AM
elken2004 (Australia)
Registered User

elken2004 is offline
 
Join Date: Jan 2015
Location: boronia
Posts: 35
Reply

Hi Lee,

I just found your thread on the focuser you built.
Nice work

My one is using the motor direct to the 10:1 shaft, but in hindsight I might use a pg5 nema17 as Robert Brown suggested to me a couple of weeks ago, but holidays caught up with me.
I have now ordered one, I should have it by the time I get back.
Originally I had the issue of the stepping being to slow.
But due to Robert's very fast response to writing new code for his "MyFocuserPro" It now drives very quickly over a 4 inch range.

My one does lose some steps, but I think this is only when driving full speed, from home to say 10,000 steps. Slippage on the 10:1 shaft, even tho I had adjusted this to fairly tight, it still must slip.
It's not used manually now so the tightness is not a problem, but don't want it to cause undue wear on bearings etc.

Oh PS my focuses are all rack and pinion type, so that's what I am going to direct drive using the PG5 Nema17 to carry the torque load.
Clive.
Reply With Quote
  #7  
Old 02-01-2016, 10:56 AM
codemonkey's Avatar
codemonkey (Lee)
Lee "Wormsy" Borsboom

codemonkey is offline
 
Join Date: Jul 2013
Location: Kilcoy, QLD
Posts: 2,049
Hmm, you might find that even a hint of skipped steps while racking out will be a good indicator of issues when you get it out under the stars. Mine did that but seemed fine with smaller movements (400 steps, vs 10000) and I found it unusable under the stars.

Anyway, sounds like Robert has given you some solid advice: a PG5 Nema 17 should be fine... a quick look says you can get a max torque of 283oz-in. My motor is rated at 198oz-in and is performing fine while full stepping at < 75% max rated current.

I was warned off using the 8:1 shaft on my Moonlite by Ron from Moonlite, but he didn't specify why exactly, maybe just some concern about potential for load on the small shaft? I dunno, but I ended up attaching mine to the main shaft.

Mine's fairly different from what I posted previously. Different motor (previous one was rated at 2a, and trying to run it on the main shaft with a driver capable of delivering at most 0.75a was futile, even full stepping), and different housing etc.
Reply With Quote
  #8  
Old 07-01-2016, 01:41 PM
elken2004 (Australia)
Registered User

elken2004 is offline
 
Join Date: Jan 2015
Location: boronia
Posts: 35
pics

I now have a TFT version of the MyFocuser Pro built now

Full line description
Attached Thumbnails
Click for full-size image (IMG_6215 (Medium).JPG)
149.1 KB26 views
Click for full-size image (IMG_6218 (Medium).JPG)
165.5 KB34 views
Click for full-size image (IMG_6219 (Medium).JPG)
116.7 KB32 views
Reply With Quote
Reply

Bookmarks

Thread Tools
Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +10. The time is now 12:07 AM.

Powered by vBulletin Version 3.8.7 | Copyright ©2000 - 2020, Jelsoft Enterprises Ltd.
Advertisement
Limpet Controller
Advertisement
Testar
Advertisement
Bintel
Advertisement
NexDome Observatories
Advertisement
Astronomy and Electronics Centre
Advertisement