You shouldn't even have to "SWAP" any wires. Since forever there has been this problem and fortunately it has become common design amongst manufacturers of stepper motors to wire up the connectors so that simply reversing the stepper motor plug will reverse the rotational direction of the motor.

So let us know what steps solved the problem. This isn't just a prurient interest.. if you tell the group how it was solved, maybe one of us will remember the solution for the next person who has these problems.

We all learn together!

Note: some people don't like socketed modules because they think they'll go crufty over time and lead to intermittent problems. That may be so but it is very easy to solve this by just plugging and unplugging a few times to clean up the contact points. The real reason is because we use such low cost modules that may be prone to failures (and sometimes 'stuff' just happens) its so much easier to replace a socketed module than to unsolder it from a PCB. If you've ever done that, you won't want to do it again - trust me!

I just bought some broken 3D printers at a surplus sale in order to salvage the stepper motors from them. I got 9 steppers for $6.00 US. None of them have any model numbers or anything. I have found that in turning the spindles with my fingers that some of them are much stiffer to twist. Like the magnets are much stronger in them. Am I correct in assuming they would have more torque than the others? They all look to be the size of Nema 17 motors.

For your information the problem was temporal solved.

After I have disabled the feature section, I got control over the OnStep STM32F303 controller.
Thanks for this hint from James in the indi forum.
I have to find another solution for my DEW Point heater. Something must be changed within Ekos or KStars that this happend. The systems runs quite stable without any failure before I updated kstars with Astroberry. At that time I used the OnStep Firmware 5.1 when the failure accured.
Anyhow....
I'm planning to switch to MaxESPV3 controller where I can control a field-rotator with the second Focus stepper. The PCB is already fully equipped for testing. The Advantage of STM32 is the very low power consumption in comparison to MaxESPV3.

Thanks to all OnStep developer for this really nice Project and their work.

Joe

That is very interesting as when I was doing this build originally I was pointed (lol) to a reference that the original EQ6 ratio was 3.91667:1....I will try this is and see what happens - Thanks!

James,

What motors are you using and are they available from sources (hobbyist, ebay, amazon, distributors)?

The fork is surely different so the motors, their size, and their torque, not your mounting of them is what I care about.
The ETX125 fork is bigger than that of the 60 and 70.

I assume the mounting plus the gearbox you've designed is what the CAD file is for, assuming I can even read it.

Plus I don't do 3D printing having a small lathe and a drill press/milling attachment.

Why are you using encoders, by the way?

Mark C.

On Sat, Jul 31, 2021 at 04:11 AM, Howard Dutton wrote:

I should add... limited to whatever the fastest speed the MCU/design can achieve (the DESIRED part.)

If desired, would I have a few suggestions for the Onstepx?

When run the focuser via "go to half home position", it would be great if you could stop the "homing" with the pressure on any of the Focus direction keys.

It would be cool even if you could enter the um number directly. Or a few buttons on which you can store the positions. I have noted the different Focus settings. Such as Camera 1 with Reducer or Camera 1 with Barlow 2x ... etc. ? :)

On Fri, Jul 30, 2021 at 01:32 PM, Mike Ahner wrote:

Hi Seven, just swap wires to the motor and it will reverse direction.
There are 4 wires to the motor, 2 pairs of wires. Choose 1 pair and swap those 2 wires.
There is a config.h entry to reverse Axis 1&2, I'm not sure about the focuser axis. But I prefer to rewire the motors and not have to remember changes to config.h whenever I upgrade.

Yes you are right. It is better to swap the cables and turn off the "Driver_Reverse". I'll do that as I find some time.

Anybody got an experience or suggestions on this, adapting a Meade ETX125?

The challenge is fitting a suitable stepper motor/gearbox/pulley combination into the DEC arm.

The electronics and software are of no concern - I've done five GEM conversions and am aware of the various PCB options.

As I said, the challenge is the form factor of the motor/gearbox/pulley combo while achieving reasonable torque.

The mount already has four leads coming up thru the polar axis so all the electronics can fit in the base, which is quite large.

Right now my leading contender is the NEMA8 of StepperOnLine with 1:19 gearbox with pulley/belt to transfer the output of the gearbox to the worm shaft.

The 1:19 gearbox ratio is acceptable because the axis worm gear ratio is 1:60, so one worm rotation is a full 6 degrees!

But it would be a tight fit (length due to the size of the bump-out on the DEC arm) and is expensive, nearly $50.

So any suggestions as to other options (I've been looking on Ebay as well) would be appreciated.

Mark Christensen

The Wemos D1 mini (not min Pro) will give you wifi capability.  They are very reasonably priced.  I use it with an old Android phone to do the Goto alignment, and then switch to Sky Safari on my ipad to do the Goto slewing.

On Sat, Jul 31, 2021 at 04:09 AM, Howard Dutton wrote:

happen at the _SLEW_RATE_DESIRED speed

I should add... limited to whatever the fastest speed the MCU/design can achieve (the DESIRED part.)

On Fri, Jul 30, 2021 at 11:31 AM, Seven Jones wrote:

Where is the "home speed" defined for the FOCUSER?

Same as the mount settings there are two kinds of focuser movement, a goto and a guide.

The move home or to a designated location (as the ASCOM driver can do) happen at the _SLEW_RATE_DESIRED speed.
Guides, as the [<<] [<] [>] [>>] buttons on the website (etc.) do happen at the slow or fast rates.

The fast guide rate is 1mm/s and as I've written below, that's not going to change in OnStep.

On Thu, Jul 29, 2021 at 12:54 PM, Seven Jones wrote:

that's the other way around with me?

Hi Seven, just swap wires to the motor and it will reverse direction.
There are 4 wires to the motor, 2 pairs of wires. Choose 1 pair and swap those 2 wires.
There is a config.h entry to reverse Axis 1&2, I'm not sure about the focuser axis. But I prefer to rewire the motors and not have to remember changes to config.h whenever I upgrade.

On Fri, Jul 30, 2021 at 01:32 AM, <mil-cha@...> wrote:

Hello,
I have the same problem with my stepper 400 steps and Baader focuser 1:10. 
for 1 Stepper revolution i get only 2,59 mm foc. travel (2590um) -> AXIS4_STEPS_PER_MICRON   400/2590=0,15
With AXIS4_SLEW_RATE_DESIRED  set to max. 5000 I measused 1 revolution of stepper takes aprox. 15 sec - it means full travel 40 mm takes 4 minutes (too short for to make a cup of coffe and too long for my patience).
As Seven wrote " the automatic half focus return need only 3-4 sec for the same way" Is there a settings that allows to get the speed of automatic half focus? I use the gamepad with SWS to control the telescope, but the control of Focuser is unuseable. It is way too slow.

Thanks for any suggestion

At the moment I can live with speed. My focuser is not so extremely slow as yours.  
But I will review the settings and also what Howard has written.

<Not sure but keep in mind that some Config.h settings, like the axis reverse ones, can be overridden if the runtime configuration option (in the SWS Config page) is active.>

Where is the "home speed" defined for the FOCUSER?

On Fri, Jul 30, 2021 at 06:45 AM, Jamie Flinn wrote:

3.916667 _> 3.916....it dropped my stepsperdegree  just a smidge - it seems to have an effect - that number 3.91667 coms form a 48/12 spur gear - now I am using belt and I suspect that the tooth angle/pitch in spur gear actually has an impact that is not there with the belt (sure it has 48 teeth but not the same angles - My RA drift was enough that it needed to be reacted to which when guiding can cascade to other problems every time you must move, so trying to reduce the NEED for guide motions and it does seem to help - my gotos and platesolving are all still great...I am sure I will be tweaking further

Spur gear or timing belt.  It is a fact that the tooth counts determine the overall ratio right up to the point that the mesh of teeth/belt fails (belt rides up on top of the teeth for example.)  Sure there can be an (usually insignificantly small) higher/lower ratio with tooth form and whatever imperfections at play but it will average out to the exact ratio.

Since 48/12 = 4 that spur gear pair's average ratio is exactly 4:1 not 3.91667:1, or anything else.

S109 are quite high current you may be able to get cheaper LV8729s, depending on the current draw of your motor - best practice is to use only 40-50% of the max motor current from wiki recommendations.

If you want a better compromise with goto's and accuracy TMC2130 (must be SPI version) or the higher current TMC5160 - these offer mode switching from high microsteps for accuracy tracking to low microsteps for goto.  Trade off is higher cost - maybe twice as expensive.

see https://onstep.groups.io/g/main/wiki/4464

The WeMos D1 mini uses a CH340 USB-to-serial interface chip so that's the driver that you need. Windows should locate and install it automatically when you connect it.