Go Back   IceInSpace > Equipment > ATM and DIY Projects
Register FAQ Calendar Today's Posts Search

Reply
 
Thread Tools Rate Thread
  #1  
Old 02-06-2015, 10:10 PM
graphworlok (James)
Registered User

graphworlok is offline
 
Join Date: Apr 2011
Location: Victoria
Posts: 54
Arduino sketch to talk limited LX200 protocol

I have not tested it in "the field" yet

But PHD will register it as a telescope mount using the LX200 under both Windows/ASCOM and Linux/INDI, and i think I've got the main commands for guiding in place.

Currently its configured as a replacement for a EQ3's GS-280 handset, using 8 of the arduino's GPIO's to toggle the coils via transistor arrays, rather than a specialised stepper driver

TODO's: timed movement commands, testing, dew control would be nice.

https://github.com/graphworlok/Equat...C_LX200_Driver

Due to an odd duty cycle on the EQ3's GS-280 handset, i used the following sketch to approximate/improve the timing:

https://github.com/graphworlok/Pulse...Second_Counter
Reply With Quote
  #2  
Old 03-06-2015, 07:11 AM
bojan's Avatar
bojan
amateur

bojan is offline
 
Join Date: Jul 2006
Location: Mt Waverley, VIC
Posts: 7,065
Watching this space
Reply With Quote
  #3  
Old 04-06-2015, 09:16 PM
graphworlok (James)
Registered User

graphworlok is offline
 
Join Date: Apr 2011
Location: Victoria
Posts: 54
Minor update..

Tested the sketch again with motors actually attached to make sure i had the pins assigned correctly to suit my specific wiring -All good, commands work as expected - Motors turn, change speeds and stop.

I'd been pondering using some of the inputs for a push-button controller - Its not at all hard, just more wires and components and logic in the sketch that i think probably is not needed right now - And i should be able to get the same functionality out of most of the software clients anyway. If i added it, the main issue would be "when do i ultimately decide what takes precedence"

The main things preventing me from testing are the clouds, and my homebrew autoguider setup (finderscope and camera) - Its quite hard to pick up any stars with it. I'm tempted to try print up an interface to connct one of my other prime lenses (135mm or 50mm, M42 thread) to the webcam and see how i go.
I think i need to bodge up a temporary cable to connect the DIY stepper for testing. Once i know everything works, i'll print out an enclosure for it all that can mount somewhere convenient
Reply With Quote
  #4  
Old 11-06-2015, 10:59 PM
graphworlok (James)
Registered User

graphworlok is offline
 
Join Date: Apr 2011
Location: Victoria
Posts: 54
Anybody with a "Real" LX200 around..?

So, tried it out tonight.. Incredibly clear skies in Melbourne

PHD2/Ascom spoke to the Arduino fine, and both motors were active

However it would not guide correctly, and kept popping up messages about needing longer guiding intervals. Also, rather than moving at tracking rate with the occasional correction, it seemed to be only driving the motor when sending correction pulses - I'm unsure of the correct behavior, not having a "real" mount to work from.

Packed up the arduino for the night, and taking some pics with the kit 18-55mm lense that came with our Eos40D - havent played with that in years, and a friend in Canada wants me to take some images of the same bit of sky 6 months apart - so the SCP @55mm it is!
Reply With Quote
  #5  
Old 12-06-2015, 02:22 PM
graphworlok (James)
Registered User

graphworlok is offline
 
Join Date: Apr 2011
Location: Victoria
Posts: 54
Think i figured it out..

My code is treating the slew commands incorrectly - - found somebody who had implemented the same thing on a PIC and added some brief command descriptions here:

http://www.nfilipovic.com/electronics/lx200-autoguiding

It was his description of :Q# that cleared things up:
"Resume tracking by nominal RA speed"

So the movement commands are something i need to apply relative to the "standard" tracking, rather than a stationary mount.



The only other issue is that finding a guidestar with my poor mans guidescope is a real pain

And some of the hardware "bumps"

Now, the long wait for another clear night... (Though one cloudy night to write the code would be ok!)

Edit: Code's updated, sky is clear!
I dropped one of the screws for my homebrew motor mount last night, but should be able to machine/bodge something up.

Last edited by graphworlok; 12-06-2015 at 08:10 PM.
Reply With Quote
  #6  
Old 12-06-2015, 09:45 PM
graphworlok (James)
Registered User

graphworlok is offline
 
Join Date: Apr 2011
Location: Victoria
Posts: 54
It works!

Breaking out the camera to take some long exposures!

Guided:
http://en.crypt.net.au/Astro/10Minut...irst_Light.JPG

Unguided: (using my apparently not-at-all-correct stepper timing)
http://en.crypt.net.au/Astro/10_Minute_Unguided.jpg

Unguided: Using factory stepper controller:
http://en.crypt.net.au/Astro/10_Minu...tock_motor.jpg

Still some tweaks required, but i'm happy for tonight!

Last edited by graphworlok; 12-06-2015 at 11:10 PM.
Reply With Quote
  #7  
Old 13-06-2015, 06:51 AM
bojan's Avatar
bojan
amateur

bojan is offline
 
Join Date: Jul 2006
Location: Mt Waverley, VIC
Posts: 7,065
Thank you for the update .
As soon as I am finished with my 3D printer (I still may need that additional Arduino board if case of some catastrophic event), I will try this on my LXD75 (witch came with simple controller only, I bought it specially for Cairns solar eclipse).

BTW..
Couple of years ago I was playing with this solution for my permanently mounted EQ-6: http://projects.gbdt.com.au/eq6-1/
And, currently I am using SoundStepper (and I am very happy with it) (http://soundstepper.sourceforge.net/)
Both solutions "talk" LX200 language
Reply With Quote
Reply

Bookmarks


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 07:23 PM.

Powered by vBulletin Version 3.8.7 | Copyright ©2000 - 2025, Jelsoft Enterprises Ltd.
Advertisement
Bintel
Advertisement