Arduino + Easydriver stepper focuser

[Nico13 (Ken)]

Recently I had my Rigel Systems NStep stepper focus driver quit on me and so being a bit budget conscious looked for an alternative.
Hearing so much about ARDUINO decided this was the way to go. I started with an ARDUINO UNO board and a ULN2003 stepper driver and some basic code and soon wound up with a rudimentary but operating focus driver, but before putting it all into little boxes etc. I came across the "sgl_observatory_automation" group over on Yahoo groups, a great little recourse for this sort of thing plus more, cloud sensor, due control, that I haven't delved into yet.
Anyway the result is what you see below, total cost of about 35-40 bucks, that is for the non-genuine boards of course, if you purchased the originals add 30 or so dollars to that, the stepper motor I had sitting around so if you have to purchase one of those add a bit more. The EasyDriver does the hard work and the UNO just supplies the logic via the USB/COM port.
The software for the ARDUINO and the GUI interface all available from the Yahoo group.
All that remains to do is swap the unipolar I currently have fitted for the bipolar you see in the pictures.
This setup is also ASCOM compatible and will apparently run via ASCOM controls but I haven’t tried that as I think the standalone GUI is better at this stage.
Comments and questions welcome.

[rcheshire (Rowland)]

Looks good Ken. Very neat and tidy. Glad you got it working.

I've just ordered an EasyDriver to play with.

[Nico13 (Ken)]

Thanks Rowland, yes the stepper that I'll be using now is of much higher quality so I'll rebuild the mounting on the focuser to fit it to the ten to one side and that'll give me very fine control.

[Astroman (Andrew Wall)]

Nice work Ken, I have my Easy driver and Arduino compatible board (Eleven from Jaycar) It works well with the stepper motor I have, which I have a separate 9v 3A Wall mounted power supply for. I have also ordered the Pulleys (1 x 20mm and 1x 40mm both 2.5mm pitch and 9mm wide, it's all I could get from the place I got them from) which will arrive soon, but the pulleys come un-bored so I need to find somewhere to get the holes bored out for me. Would have liked continuous movement on the SGL_focuser but what it is will do fine for now, should work fine once everything is connected.

I like the box you have where did you get it from?

[MrB (Simon)]

Originally Posted by Astroman

I like the box you have where did you get it from?

It's a Jaycar HB5960
(I can't believe I still remember that, I left Jaycar almost 5 years ago!)

http://www.jaycar.com.au/productView.asp?ID=HB5960

[Astroman (Andrew Wall)]

Originally Posted by MrB

It's a Jaycar HB5960
(I can't believe I still remember that, I left Jaycar almost 5 years ago!)

http://www.jaycar.com.au/productView.asp?ID=HB5960

good memory, thanks

[MrB (Simon)]

Originally Posted by Astroman

good memory, thanks

Haha, remembering the case isn't a stretch, still remembering the catalogue number is what scares me

[Nico13 (Ken)]

That's good Andrew, sorry I didn't get back sooner but Simon with his scary memory has come to the rescue, thanks mate.
I'm about to build a second one but this time with an ARDUINO Nano, should be able to fit it in a box about a quater the size.
If you can find someone with a small lathe they will soon bore those pully's for you, I could do them on my lathe but its a but far to go hey.
Also since posting those pictures above I've also connected pin #3 from the UNO board to the sleep pin on the Easydriver and that puts the board to sleep after about twenty seconds of sitting idle so it removes power from the motor coils to allow heat reduction on the easydriver chip as it can get pretty bloody hot depending on how high you have set the motor current.
Only be a problem if your focuser has any creep issues.

[Astroman (Andrew Wall)]

Using the Nano, is it the same procedure as using the UNO or similar? What benefits besides going smaller does it have?

Interesting you are getting heat issues, I had mine sitting on the table and I had forgotten I had it on and running, the Easy driver board was warm but not hot at all. I don't have the sleep mode connected...

Some interesting talk on the SGL group though regarding the right way to hook up the power...

[Nico13 (Ken)]

Originally Posted by Astroman

Using the Nano, is it the same procedure as using the UNO or similar? What benefits besides going smaller does it have?

Interesting you are getting heat issues, I had mine sitting on the table and I had forgotten I had it on and running, the Easy driver board was warm but not hot at all. I don't have the sleep mode connected...

Some interesting talk on the SGL group though regarding the right way to hook up the power...

I had the current limt set too high so at idle it was just getting a tad warm, possibly around 65 deg as I could still keep my finger on it for a short period.
The chip apparently has a thermal shutdown at just over 160 deg C so no real porblems
Size and price by a few dollars is the only advantage that I know of for the Nano Andrew and I do want a second focuser for my ED80.
Asside from that I just like playing with this stuff I guess as it's relatively cheap fun and useful in the end.
The Nano pin connections are the same I believe so no operational differences to worry about.
Yes I have also been following the SGL conversation to see what comes out of it you never know what little helpfull tit bits you can pick up from chat.

[rigelsys (Leon)]

what were the symptoms for your nSTEP quitting?