Electronic Focuser.. almost there :)

[davidpretorius]

i have this one arriving today or tomorrow. it is usb driven as the printer port is already taken up by imaging software for long exposures on the modified toucam

http://www.ar.com.au/~softmark/page44.html

[elusiver]

yeah i looked at that... but from memory it couldn't be used indepently of a PC.. which is what I wanted so I could use it as a hand controller.


el

[mch62 (Mark)]

What's involved with using it as stand alone.

Thought about using small timing belts to the original focuser knob.
some of the robofocus mods use this method and as you say it's not a permanent change.

[elusiver]

the software i've written for it does work with XP.. it's based on some chinese source i found on the net for driving it under xp.. out of the packet the kit doesn't work with 2k/xp.

the circuit knows when its plugged into a computer. So you're hand controller is also your interface box.. so when you plug the interface box in to the computer it automatically switches to 'pc mode'.. then indepenant of PC you can use the interface box as the hand controller. To get it work to properly as a hand controller only took a couple of DPDT switches so it was sweet, and the manual speed control is in the kit.

el

[davidpretorius]

yes, xp has tightened up security so much the printer port is not as easy to get at.

that is why the usb port versions are starting to be more wide spread

[mch62 (Mark)]

just another link for steppers and controllers

http://www.oatleyelectronics.com/stepper.html

[davidpretorius]

great find, exactly what i have been looking for!!!

[elusiver]

hey guys... a couple of people have asked about this project.. it's progress.. and copies of the source.. well.. i'm selling the source for a bargain price of $100,000,000,000!!!! j/k

in all seriousness.. i think the last time i worked on it it was pretty much done.. had the mount made up and it worked quite well.. to a point.. and i'm sure it could be refined down to a very fine control.

At the moment though.. well.. i'm kinda homeless.. the mrs burnt down the kitchen.. noone was hurt.. but my pc is in storage.. and that's where the source is. Once we get back home i'll post the source up here.. so you can do whatever you want with it.

it's also why i haven't visited iis much.. i miss my dob.. real bad.. damn fire and burning....


el

[ballaratdragons (Ken)]

Ellex!!!

Wondered where you went!!!

Gee, not good news mate, but nice to hear from you again. Welcome back!

I hope you get everything sorted out soon.

[Aprid]

Have a look at www.interinar.com I picked up a stepper controller assembled and motor for approx $70AU delivered can operate in PC or standalone just req'd a couple of SPST switches and a potentiometer soldered to microstep, reverse and contol speed, works great in standalone I haven't tried running it with a PC yet.

[DavidH]

Hello Folks,

Thought I'd add my .02 worth to this thread by posting a snap or two of my homebrew stepper focuser. Stepper and gear are from a photocopier. The focuser is a JMI mini crayford. It has three holes in the focus knobs as standard. I simply drilled and threaded the nylon gear for the 3/32 bolts and use the bracket from the photocopier to support the motor. Took a little bit of playing with to get the gear centred on the focuser shaft, so that it would mesh properly with the motor gear.

Have also seen similar motor/gear combinations in the carriage movement of flatbed scanners.

The control of the stepper is via an Atmel microcontroller which has an infrared interface to a TV remote to use as a handpad. Sometime I intend to convert this to a radio handpad, and maybe write an Ascom driver for it. This will have to wait until I learn enough about writing drivers to actually do it, however. Does anyone here have any experience with this?

[Yogie-One (Paul)]

Came acros this thread as I have also fitted a stepper motor to my scope, but, have a setup for my scope, which uses only a battery, a 12 position switch, 8 diodes, a 5 or 6 wire stepper motor, a mounting plate and a few gears.

The conection causes the stepper motor to follow the switch, forward or backwards, enabling it to be used as a driver for a focuser.

Total cost $3 (with stepper motor from old printer)

[iceman (Mike)]

Great work Yogi! Perhaps you could write an article with bigger pictures and I can use it in the articles section!

[DavidH]

Well done Yogi, a simple but effective design that I am sure a lot of people could and will use.

[Karls48 (Karl)]

Here is a link to build simple and cheap unipolar stepper motor controller. I have build push button version and it work great.
http://www.beowulf.demon.co.uk/serial-stepper.html