Cheap & Easy Parallel Port Focus Motor Controller

[mtodman (Matt)]

A while back I decided to have a go at building a cheap stepper motor controller & writing an ASCOM driver to allow it to control a focus motor. As it came to pass, I ended up getting a robofocus unit which is working well but I still managed to follow through with my DIY parallel port focuser as well. Whilst I never hooked it up to my focuser, I did get it all going "on the bench".
Perhaps someone it trying something similar, in which case this may help give them a head start. It comes with no guarantee that it's 100%. I'm sure that there are a few bugs in there but the basics seems to work.

Anyway, after much looking around for appropriate motors & controllers, I figured the easiest way to start was to go with a off-the-shelf product. I decided on the KV3594 stepper motor / controller kit from Jaycar
http://www.jaycar.com.au/productView...r&form=KEYWORD

I then set about writing an ASCOM driver to controll this specific kit. I ended up writing an ASCOM V5 driver (in VB.net). It can be downloaded from the following link
http://astroromp.com/astronomy/stepp...or_control.htm
Please note that this link contains both the source & executable files (ie, the ASCOM installer).

Good luck

Matt

[Spanrz (Brett)]

Originally Posted by mtodman

I then set about writing an ASCOM driver to controll this specific kit. I ended up writing an ASCOM V5 driver (in VB.net). It can be downloaded from the following link
http://astroromp.com/astronomy/stepp...or_control.htm

Matt

Hey Matt,
I am in design of stepper system for the Dob. How long/hard was it to write an ASCOM driver?
I have done very little in the way of programming, bit here and there (DOS/BASIC/HTML/JAVA), but I understand what code and all that is..

I do have VB, but I haven't got that far yet. I have seen a few software programs around to control scopes made by individuals, with the basics of control, which is giving me ideas to work with.
"Nothing special, but it works", type programs.

I have about 3 ideas to control the scope with software (and the hardware), but choosing the ideal way for me is a hard choice.
The ASCOM driver, a mean type of 3D CNC software (MACH3), or a hand held controller (it will have to be a pulse generator) with all tracking speeds to boot.

The ASCOM driver, would be nice, but not sure how long to code it.
The MACH3 software is a bit more complex, but coding that could be a bit cumbersome. But I know it will work.
The hand held controller (variable pulse generator) sounds good, but I would have to study the concept a bit more.

Can you give me an idea what is involved in coding an ASCOM drver?
Thanks.

[mtodman (Matt)]

Hi Brett,
It sounds like I have about the same programming experience as you.
Luckily, ASCOM V5 comes with some Visual Studio.net application templates which really simplifies things. After familiarising myself with VB.net (quite different to VB v6), I found the going reasonably easy. I guess all up it took me a week to write (fiddling at my PC after dinner each night).
You should be able to use my source code as a starting point if you want to write your own.

Cheers

Matt

[hikerbob (Bob)]

Brett you might want to have a snoop at some material I've posed at http://forum.sparkfun.com/viewtopic.php?t=17243 which is my first try at using an Arduino to generate the variable frequency source to control a stepper motor (very sweet to). That was the first step in a hand controller which is well on the way. I've done quite a bit since but have not got it to a state to publish yet (happy to share privately).

My latest play involves lifting a couple of pins on the EasyDriver to give access to other step modes but I've not powered that up yet nor have I changed the code on the Arduino to deal with it, maybe tomorrow.

Eventually I'll try and get the Arduino talking to my Argo Navis (and maybe Ascom so Matt's link may be invaluable).

Bob