DIY DSC arduino project for Skywtacher dobsonian

[agrauballe]

Hi there,

I have a Skywatcher flextube 250px dobsonian I would like to transform into either a goto or push to. 

I have seen the option of buying an upgrade kit which adds Synscan functionality, but it has a rather steep price tag.

Also there is the Nexus option which is also nearly in the same league price wise.

Instead I'm looking at building a solution myself using an arduino board, bluetooth module and encoders.

I've searched every bit of the internet to find guides on the encoders, but have not managed to find any how-to.

Do anybody know where I can buy encoders for my scope, preferable in EU?

Which encoders would you suggest? they do not need to be premium but indeed usable 

Have you seen any guides on how to mount the encoders?, I'm most concerned on how to mount the encoder on between the OTA and the base.

Br,

Anders

[happy-kat]

Hi you might find these posts interesting.

http://stargazerslounge.com/topic/239782-goto-all-checked-out-but-no-images/?fromsearch=1

http://stargazerslounge.com/topic/231932-diy-telescope-goto-drive-link/?fromsearch=1

[Ajohn]

This might or might not be of interest

http://code.google.com/p/wheel-encoder-generator/

It will print an absolute  grey encoder with a resolution of 4096 such as this, it proves a little bit too much for a 600dpi laser to print accurately at 150mm dia.  I just tried it.

A resolution of 4096 gets down to about 5' direct absolute encoding. I'm not sure what the resolution of the rather expensive absolute encoders are that are used on some high end mounts.

It will also print ordinary encoder wheels. Those might be of interest to people who are interested in servo motor drive.

John

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[Scooot]

The nexus unit usually uses these us digital encoders, I bought mine from Australia.

http://usdigital.com/products/s6

I think these are also ok.

http://www.teleskop-express.de/shop/product_info.php/info/p1808_ArgoNavis-Encoder---Aufloesung-10-000-Schritt-ohne-Kabel.html

They are 10000 step optical shaft rotary encoders.

[Ajohn]

It's possible to way way more ticks than that see

http://www.renishaw.com/en/resolute-linear-absolute-encoder-options--10936

Some version of this has been fitted round a ring for the direct drive telescope motor project that is about on the web. I've been wondering about cheaper versions which are bound to be about and may be based on vernier caliper etc type technology.

They also produce rotational version

http://www.renishaw.com/en/resolute-rotary-angle-absolute-encoder-options--10939

John

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[agrauballe]

Thanks for all the answers and for pointing me in the right direction.

Actually what I need is this one: http://www.teleskop-express.de/shop/product_info.php/info/p5065_ArgoNavis-Encoder---Anbaukit-fuer-Skywatcher-Dobsons.html

This enables me to fit it to my scope.

But in the end I either need a unit like this http://www.teleskop-express.de/shop/product_info.php/info/p1807_Argo-Navis-Teleskop-Computer---Digitale-Teilkreise---ueber-29-000-Objekte.html

or to build an arduino unit myself.

Maybe I'm better of by buying the Upgrade kit which also gives me tracking as a bonus: http://teleskopy.pl/product_info.php?products_id=2220&lunety=Upgrade_Kit_GoTo_do_Dobson_10%27%27_Sky-Watcher

Br,

Anders