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Building a DIY autofocuser -how easy


Bottletopburly

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I am planning to have a go at this -I have a few more bits to get just yet.

 

If you beat me to it you can tell me or I can tell you :D

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1 hour ago, Ibbo said:

I am planning to have a go at this -I have a few more bits to get just yet.

 

If you beat me to it you can tell me or I can tell you :D

Likewise :thumbsup:

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The PDF document of the build is very comprehensive so should be followable, looks tough though.

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Which pdf covers the build.

There seems to be loads and loads of options

 

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2 minutes ago, Graham said:

Which pdf covers the build.

There seems to be loads and loads of options

 

2nd one down minimal focuser,looking too hard for me lols

Edited by Bottletopburly
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failed to get the sketch to upload to the Uno last night.

 

Edited by Ibbo
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I think I solved the issue this morning.

I went back to basics and found i was doing a svery simple error.

 

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I have my nano stepper focuser working.

 

Once I had the correct kit and worked through the assumed things you are supposed to know with the Ardunio and its sketches it did not take taht long.

 

I made up the one by Robert brown and have done it with a basic set up.

Just need a box and I think I may use a belt and cog system for the short F/L scope as the critical zone is much smaller.

 

 

 

While in the files and reading I found thisinfo

 

Should I Connect the Stepper Motor to the Fine Focus Knob?
NO. There is a misconception that driving via the 10-speed reduction is safe. This is not good idea as the mechanics and manufacture of the mechanisms employed mean that they are not robust enough to have that level of force (from stepper motors) consistently applied to them. There are small gears (normally plastic or cheap metal) involved that do not have the strength to handle the force a stepper motor can apply. Over time this results in increased wear and tear in the small gears, leading to increased backlash, or if the focuser limits are exceeded, the complete breakdown of the fine focus mechanism by catastrophic failure (breakage) of the gears - in other words, not a good idea.
So why do some users try connecting to the fine focus knob? The answer is that it already provides a 10:1 reduction so this increases the resolution without any cost. The downside is the cost in replacing the focuser mechanism when the 10:1 reduction is damaged by the stepper.
If you need to drive the fine focus mechanism (FFM) then it would be better using a belt drive to prevent damage in the event of exceeding the focuser limits. It is not recommended.
Remember NOT to use the Focus Lock Screw on your focuser; leave the screw loose or remove it. The Stepper motor will hold the focuser in place. If you leave the screw in and accidently tighten the focus lock screw, then serious damage can occur to the stepper motor or focuser.

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What software are you going to use for the auto focus Steve. 

Can you post up some photos. 

 

Further to the above.  If you are using a stepper motor then there is no need to use the fine focuser knob as the motor will already supply the very fine adjustments required unlike the DC motor I and probably most other folks use at the present time. 

Edited by Graham
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4 hours ago, Ibbo said:

I have my nano stepper focuser working.

 

Once I had the correct kit and worked through the assumed things you are supposed to know with the Ardunio and its sketches it did not take taht long.

 

I made up the one by Robert brown and have done it with a basic set up.

Just need a box and I think I may use a belt and cog system for the short F/L scope as the critical zone is much smaller.

 

 

 

While in the files and reading I found thisinfo

 

Should I Connect the Stepper Motor to the Fine Focus Knob?
NO. There is a misconception that driving via the 10-speed reduction is safe. This is not good idea as the mechanics and manufacture of the mechanisms employed mean that they are not robust enough to have that level of force (from stepper motors) consistently applied to them. There are small gears (normally plastic or cheap metal) involved that do not have the strength to handle the force a stepper motor can apply. Over time this results in increased wear and tear in the small gears, leading to increased backlash, or if the focuser limits are exceeded, the complete breakdown of the fine focus mechanism by catastrophic failure (breakage) of the gears - in other words, not a good idea.
So why do some users try connecting to the fine focus knob? The answer is that it already provides a 10:1 reduction so this increases the resolution without any cost. The downside is the cost in replacing the focuser mechanism when the 10:1 reduction is damaged by the stepper.
If you need to drive the fine focus mechanism (FFM) then it would be better using a belt drive to prevent damage in the event of exceeding the focuser limits. It is not recommended.
Remember NOT to use the Focus Lock Screw on your focuser; leave the screw loose or remove it. The Stepper motor will hold the focuser in place. If you leave the screw in and accidently tighten the focus lock screw, then serious damage can occur to the stepper motor or focuser.

How hard did you find doing it Steve  , did you have to program the nano using IDE and if so how easy was it 

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i used the mydiyfocuser2 a nano and a drv8825 and I steeper I had in stock.

once I realised I had to copy the myguides to the nano library it went well.

took me less than an hour to wire it up and about the same to figure the software but about 10 mins once i figured the myguides out.

 

it runs in a stand alone windows bit of software or under ascom in maxim or what you are running.

 

I oreder another stepper with a gear box on it

 

Nema 17 Stepper Geared Motor 27:1 Planetary Gearbox 0.4A CNC Robot 3D Printer.

 

just need a box to put it inand tidy the wiring and solder it up

 

bearing in mind I only have to basic running ie motor only no temp no readout etc etc

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Sounds good to me. 

If you get time can you post up some photos. 

Thanks 

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16 minutes ago, Ibbo said:

i used the mydiyfocuser2 a nano and a drv8825 and I steeper I had in stock.

once I realised I had to copy the myguides to the nano library it went well.

took me less than an hour to wire it up and about the same to figure the software but about 10 mins once i figured the myguides out.

 

it runs in a stand alone windows bit of software or under ascom in maxim or what you are running.

 

I oreder another stepper with a gear box on it

 

Nema 17 Stepper Geared Motor 27:1 Planetary Gearbox 0.4A CNC Robot 3D Printer.

 

just need a box to put it inand tidy the wiring and solder it up

 

bearing in mind I only have to basic running ie motor only no temp no readout etc etc

Awesome work, I will put it on my to do list ? not great with electronics so I may be visiting this thread regularly ?

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If either of you need a bracket to mount the kit on the scope let me know and I will waterjet them for you. 

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56 minutes ago, Ibbo said:

this is t as it is now

 

WP_20180312_19_17_48_Pro

 

whats the big white board is that what they call a bread board 

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Thanks Steve. 

Yup that is a breadboard. 

 

Edited by Graham
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yep a bread board.

While I was feeding my face and then watching a bit of the idiot box the motor flt a bit warm.

I may have to reduce the current for the motor :D

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  • 3 years later...

Hi All,

Just seeing if anyone has finished there's as I'm interested in having a go myself. I bought all the bits to build the BullsEye auto focuser only to realise it only has an INDI driver and I need it to be ASCOM to run on Windows 10 and NINA.

Cheers

Daz

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