I build one myFocuserPro2 and i'm not able to made the motor rotate (Nema 17).
After searching arround for a mistake in connection , everything was ok so far.
Then , i tested the signals on my oscilloscope and see that /Enable and Direction pin work ok but the Step pin just put one pulse out (some µS) and it's done , i tryed 1 , 10 , 100 , 500 in +/- direction , i get the same :)
So , i have think i fried my Arduino nano and take a new one , but the result is exactly the same , this time i dont have connect the Stepper Driver but just tested directly on the Arduino board alone.
Does someone know how i can fix this problem ??
Cheers.
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The step pulse is very short, around 2uS
Some obvious things first
1/ Stepper only works if 12V dc supply is connected. Do you have 12V between VMOT and GND measured at the DRV8825?
2/ Have you tried turning the little pot on the DRV8825 to mid-position first
DO ALL TESTS WITH COIL POWER ON
If you had a scope and connected it to Step pin, then set the focuser pos to say 5000, then hit the -500 button, one would expect to see 500 pulses (each 2uS) on the Step pin.
If you only see 1, (then make sure coil power is ON)
1/ either the firmware has been changed?
2/ check that RESET and SLEEP pins of DRV8825 are at 5V
3/ check that ENABLE pin of DRV8825 remains LOW (at GND)
4/ or perhaps the drv8825 is suspect
The dRV8825 will easily be blown under the following conditions
1/ when you have 12V connected and you disconnect any of the stepper wires
2/ or you have the stepper disconnected, turn on 12V then connect the stepper motor
Regards
Robert
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Hi :)
Yea , the nano is ok , i found the ... error ...
it was a cold solder point on the step pin , so the a 4988 never get the step signal and , the motor cant rotate ;)
Now everythng work ok , the version is : myFP2.A4998HW203, 268
And , many thanks to share this project , i get my celestron nexstar 6 SE yesterday , and this will help me to auto-focus for astrophotography ;)
But first i will look to 3D print something that i can attach the motor to the focuser ...
Cheers.
Last edit: darthvader 2018-05-10
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Hi
That is very impressive. You have come up with a realy good easy way to mount the focuser onto any Celestron SCT type, it would even work on an 8" if scaled properly. That is very clever, well done.
Loved the video.
Cheers
Robert
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I build one myFocuserPro2 and i'm not able to made the motor rotate (Nema 17).
After searching arround for a mistake in connection , everything was ok so far.
Then , i tested the signals on my oscilloscope and see that /Enable and Direction pin work ok but the Step pin just put one pulse out (some µS) and it's done , i tryed 1 , 10 , 100 , 500 in +/- direction , i get the same :)
So , i have think i fried my Arduino nano and take a new one , but the result is exactly the same , this time i dont have connect the Stepper Driver but just tested directly on the Arduino board alone.
Does someone know how i can fix this problem ??
Cheers.
Hi
You did not say what firmware you are using?
The step pulse is very short, around 2uS
Some obvious things first
1/ Stepper only works if 12V dc supply is connected. Do you have 12V between VMOT and GND measured at the DRV8825?
2/ Have you tried turning the little pot on the DRV8825 to mid-position first
DO ALL TESTS WITH COIL POWER ON
If you had a scope and connected it to Step pin, then set the focuser pos to say 5000, then hit the -500 button, one would expect to see 500 pulses (each 2uS) on the Step pin.
If you only see 1, (then make sure coil power is ON)
1/ either the firmware has been changed?
2/ check that RESET and SLEEP pins of DRV8825 are at 5V
3/ check that ENABLE pin of DRV8825 remains LOW (at GND)
4/ or perhaps the drv8825 is suspect
The dRV8825 will easily be blown under the following conditions
1/ when you have 12V connected and you disconnect any of the stepper wires
2/ or you have the stepper disconnected, turn on 12V then connect the stepper motor
Regards
Robert
It is unusual to blow the nano.
Hi :)
Yea , the nano is ok , i found the ... error ...
it was a cold solder point on the step pin , so the a 4988 never get the step signal and , the motor cant rotate ;)
Now everythng work ok , the version is : myFP2.A4998HW203, 268
And , many thanks to share this project , i get my celestron nexstar 6 SE yesterday , and this will help me to auto-focus for astrophotography ;)
But first i will look to 3D print something that i can attach the motor to the focuser ...
Cheers.
Last edit: darthvader 2018-05-10
Hi
That is great work on your part to identify the issue. Congrats on getting it working. There are some brackets on thingiverse
Regards
Robert
Hi Robert ,
I finally made myself a bracket for the Nexstar 6SE.
You can watch the result here :
https://www.youtube.com/watch?v=HC_Z7lyolWw&feature=youtu.be
And get the CAD if needed here :
https://grabcad.com/library/celestron-nexstar-6-se-myfocuserpro2-bracket-1
Again , thanks for your work ;)
Hi
That is very impressive. You have come up with a realy good easy way to mount the focuser onto any Celestron SCT type, it would even work on an 8" if scaled properly. That is very clever, well done.
Loved the video.
Cheers
Robert