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  #21  
Old 14-01-2013, 09:47 AM
danstar10
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Ah if it need mains power the it is no good for me

I have been doing more research into the linear stepper motion controller in this link I posted:
http://www.piclist.com/techref/io/st...step/index.htm

It does not require an external PC apparently, and just need to be programmed once to my needs. I would just need to find an suitable stepper motor and a power supply.
This seems like a very similar project all be it with a more advanced mount:
http://www.youtube.com/watch?v=X4niX...xDrWCu4gvoQ2Ug

what do you make of this? Seems like it will be very accurate and a reasonable price, and it would be nice to build the circuit kit as it comes un-assembled.

I had a look at the links you posted, seems like you have had some nice results with your projects
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  #22  
Old 14-01-2013, 09:59 AM
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Merlin66 (Ken)
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danstar10,
I have an ol' double arm Trott design barndoor mount with a geared 12V stepper motor (SIA) drive.
Google "12V geared stepper motor" for many options!

I have details of the original stepper driver board, based on the SAA 1042V chip (ebay) and an R-C control.
Alan on SGL (who has done some exellent work on stepper driver motor controls for focusers) has designed and prepared a 12V PCB which he thinks will replace the old circuit and give even more flexibility. I have just received his "prototype" and need to set it up for trial.
Drop me a PM if you need more detail.
(This link may be of interest
http://www.considine.net/drowesmi/st...ontroller.html
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  #23  
Old 14-01-2013, 10:13 AM
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bojan
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Quote:
Originally Posted by danstar10 View Post
Ah if it need mains power the it is no good for me

I have been doing more research into the linear stepper motion controller in this link I posted:
http://www.piclist.com/techref/io/st...step/index.htm

It does not require an external PC apparently, and just need to be programmed once to my needs. I would just need to find an suitable stepper motor and a power supply.
This seems like a very similar project all be it with a more advanced mount:
http://www.youtube.com/watch?v=X4niX...xDrWCu4gvoQ2Ug

what do you make of this? Seems like it will be very accurate and a reasonable price, and it would be nice to build the circuit kit as it comes un-assembled...

This circuit is designed for use with CNC machines, and in it's original form and intention it does require PC (as it has STEP and DIR control inputs, see here, a bit lower on the page.)
However, if you have a suitable firmware (or if you know how to write it), this circuit can of course be used to function independently.

Ken's circuit is very complicated to build (even for me ) and those stepper drivers are not available any more (if you find them, they will blow your budget as it is set to ~50 punds).
The schematic attached below ( if you go for this solution, you can solder the circuit on protoboard) is what I used for the driver on my EQ3 mount - it is much simpler. The processor used is also obsolete, but it can be replaced with some newer PIC controller... and the only thing left to do is to write firmware for it. See discussion I mentioned earlier, about picaxe.


Perhaps, you should also have a look at PICGoTo - this board can operate independently, but later you can use it for more serious mount, you can even connect it with PC if you wish, for full blown GoTo functionality.
Attached Files
File Type: pdf 1_motor.pdf (39.0 KB, 25 views)

Last edited by bojan; 14-01-2013 at 05:14 PM.
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  #24  
Old 14-01-2013, 11:01 AM
danstar10
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thanks Merlin66, sounds intersting, but if bojan says it is very complicated for him, I guess I have no chance. I am not sure if you have been folowing the thread but I am a complete newcomer to electronics

Quote:
However, if you have a suitable firmware (or if you know how to write it), this circuit can of course be used to function independently.
bojan - i have had someone offer to program the PIC for me for the linestepper I posted- I guess that is what you are referring to? Seeing as I can buy that kit for $35 and it has everything in it I need to assemble it minus the motor and power supply I would be tempted to go with that. Are there any advantages to the design you are proposing?
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  #25  
Old 14-01-2013, 11:13 AM
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bojan
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Quote:
Originally Posted by danstar10 View Post
...bojan - i have had someone offer to program the PIC for me for the linestepper I posted- I guess that is what you are referring to? Seeing as I can buy that kit for $35 and it has everything in it I need to assemble it minus the motor and power supply I would be tempted to go with that. Are there any advantages to the design you are proposing?
If you have someone to help you with programming then go for it.

There is no real benefit with my design.. as I mentioned, I did it this way only because I still have those particular processors in some quantities.

However, maybe you can consider slight departure from the linestepper approach:

Have a look at this little motor with driver (The same I used on my EQ3)
This is only a driver, so you need processor board (this one or this one, it is similar).. you can even place ULN2003 chip (from motor driver board) on it, and this will be only necessary soldering work to be done, otherwise you can just use connectors and ribbon cable to connect them together.
This approach may be cheaper, and modular enough - so you can use it later for more serious projects (to add hand pad, or DEC motor.. it will be easy, you just have to be good to your friend the programmer )

Let me know what you think and I am willing to help you further with advice.

EDIT:
I found another one on ebay.. this is complete, assembled board with PIC controller, with STEP-DIR input (not sure which processor - please check with your friend). You just need to put in your own firmware. There are heaps of them on ebay, pretty cheap - see here for another one.

Last edited by bojan; 14-01-2013 at 08:20 PM.
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  #26  
Old 14-01-2013, 11:21 AM
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Merlin66 (Ken)
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If Alan's PCB works then I'm sure it will be made available to all amateurs...just needs a stepper motor and a 12V battery.....
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