Congratulations for this great project !!
I was already using a focuser with DRV8825 and Arduino Nano, but it was very limited.
Searching the web I found your great project, I noticed that you are using a motor NEMA 17.
I wanted to recommend a NEMA 11 gearbox, an excellent choice, it has 5400 steps per revolution with.
you can find it at: http://www.ebay.com/itm/Gearbox-27-1-Ratio-Nema11-11HS3406AG27-6N-m-0-67A-CNC-Router-Engraving-LONGS-/161394171602
(excuse my English is not my native language)
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
The only precaution I have on stepper motors is to ensure that the current rating is not too high. Even at 0.67A with both coils engagaed that becomes 1.3A which means using a DRV8825 driver chip. The steppers recommended here from omc are rated at 0.4A and work very well.
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
Hi
Yes many other stepper motors will work, I find the Nema geared motors are very good. The PG27 ot PG14 ratios work best around f5 / f7.
I hope you have it all working,
Cheers
Robert
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
Yes, the reset is normal. As stated you can prevent this by using a 1uf capacitor between reset and ground (does not work on all boards and may lead to issues in uploading new firmware).
The reset is not an issue as focuser settings are remembered.
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
Have uploaded changes to DRV8825 and EASYDRIVER - This connects EN to pin 8, meaning you can then use Coil Power to turn off the stepper motor after a move - So the documentation, schematics, pcb layour, arduino code have been changed to support this.
Please note that if you are using micro-stepping then you should operate with coil power ON.
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
To discuss any hardware issues or questions, please post here
Congratulations for this great project !!
I was already using a focuser with DRV8825 and Arduino Nano, but it was very limited.
Searching the web I found your great project, I noticed that you are using a motor NEMA 17.
I wanted to recommend a NEMA 11 gearbox, an excellent choice, it has 5400 steps per revolution with.
you can find it at:
http://www.ebay.com/itm/Gearbox-27-1-Ratio-Nema11-11HS3406AG27-6N-m-0-67A-CNC-Router-Engraving-LONGS-/161394171602
(excuse my English is not my native language)
The only precaution I have on stepper motors is to ensure that the current rating is not too high. Even at 0.67A with both coils engagaed that becomes 1.3A which means using a DRV8825 driver chip. The steppers recommended here from omc are rated at 0.4A and work very well.
Hi
Yes many other stepper motors will work, I find the Nema geared motors are very good. The PG27 ot PG14 ratios work best around f5 / f7.
I hope you have it all working,
Cheers
Robert
First, Thank you for this great project!
When I connect. via ascom or windows application, the arduino resets. Is this normal?
By adding a 1uF capacitor between reset and ground it was solved.
Yes, the reset is normal. As stated you can prevent this by using a 1uf capacitor between reset and ground (does not work on all boards and may lead to issues in uploading new firmware).
The reset is not an issue as focuser settings are remembered.
Yes, true. I'm using a Nano and uploading isn't possible when the capacitor is in place.
Have uploaded changes to DRV8825 and EASYDRIVER - This connects EN to pin 8, meaning you can then use Coil Power to turn off the stepper motor after a move - So the documentation, schematics, pcb layour, arduino code have been changed to support this.
Please note that if you are using micro-stepping then you should operate with coil power ON.