Date   

Re: MaxSTM v3 through-hole construction tips

Howard Dutton
 

On Thu, May 27, 2021 at 02:10 PM, <johnwashington1978@...> wrote:
Well, JLCPCB arrived in the post this morning and within 30 minutes or so I was up and running - I'm not too keen on the RTC dangling - I'll design up a small 3d printed block that screws between it and the pcb stand off hole - shall post it tomorrow.
I'll put that in the files section.

Other than that I didn't have any build issues - I sourced the majority of my parts from digikey - I had the leds and diodes already, used an lm7805 vreg and some ebay headers.
Technically the board isn't designed for the lm7805, they usually need stabilization caps nearby.  There's a 0.1uF but usually they need a 0.33uF too and the board doesn't have that one.  Then it's not going to be good for much current without overheating, especially if powering from 24VDC.  Might be ok, but best to use the spec'd switching regulator though.

If a wally like me can get it together and working, anyone can !!  Big thumbs up!
Thanks, these are nice boards in my opinion too, another step up in the evolution of the Max series.  Better documented, easier to source parts for, easier to assemble, better TMC stepper driver support (allowing the most important settings for all axes at runtime,) and more easily extended for BME280 dew heaters, etc.


Wemos R32 CNCV3 controller test issues #wemos

astrosathya
 

Those who have been following my build will know that I somehow managed to fry one wemos d1 R32 board because I gave 12V to it directly (though it has a Buck converter and V regulator). This time, upon advice from a friend of mine as well as Oddvar who recently completed his build, I powered the wemos using ONLY the USB cable which doubled up for comms, and powered the motors through the CNCV3 shield using the 12V SMPS.
However, one thing I noticed is the sound at the beginning, mid point (while crossing meridian i think) and end of the slew as if a large, heavy truck is slowing down. I am not sure if thats ok. I also know the its pointing in the wrong direction too. Motors are reversed maybe? Anyone who has an idea, i'll be happy to take advice from.
The video of the Test is HERE
TIA.
Sathya.


Re: hello everyone, i have a new question. If I install a powerful servo motor with encoder instead of stepper motor, will the system work? #mount

Howard Dutton
 

On Thu, May 27, 2021 at 03:53 PM, sami wrote:
I also want to get a ready plug and play onstep control box with everything the last system.this was sold? and where can i buy
We are DIY here, currently I know of no one selling complete controllers.


Re: Occasional error in guide speed - massive overcorrections

Howard Dutton
 

On Thu, May 27, 2021 at 01:51 PM, GuitsBoy wrote:
Unfortunately I'm not sure how to test this other than under the stars, and no good weather on the horizon. 
I guess you could issue commands like this from the Arduino Serial Monitor:

Start tracking...
:Te#

Set rate 2 which is 1x sidereal then guide east for 2 seconds, RA axis (normally moving at 1x) should then stop for 2 seconds...
:R2#
:Mge2000#

Set axis1 custom guide rate to 2.0 degrees/second, then move east, then stop...
:RA2.0#
:Me#
:Q#

Without the new code the following should result in 2 seconds of rapid motion, with the new code it should act as before stopping tracking...
:Mge2000#


Re: Info on timer interrupts for a port to Arduino Nano RP2040?

Howard Dutton
 

Join the developer sub-group and post again.


Info on timer interrupts for a port to Arduino Nano RP2040?

marccarrier@...
 

Hi,

I'm trying to port OnStep to an Arduino Nano RP2040 Connect on a CNC V4 shield.  I have it running with only the timers to finish reimplementing in the HAL. Everything else (command line processing, PPS, GPS TLS, WiFi, etc..) is working.

Is there documentation on the role and intervals for timer1, timer 3 and timer4? The RP2040 has a funny implementation for its timers. There is only a 32-bit microsecond free running counter and the timer interrupts are programmed to trigger on a compare register to the micro-sec "clock". There are no pre-scalar or clock source selection. The RP2040 has a bunch of these timer compare registers but only two that are 32-bits.  

I'm using TMC2209 stepper drivers with 8 microsteps by grounding the M0 and M1 pins of the 2209 (The CNC V4 has jumpers to ground that can be used).  My mount is an EQ-3 and I had sidereal tracking and GoTo working with a regular Arduino Nano. I had stripped out most features and capabilities out of OnStep to get it to fit in the small memory of the Nano. I had also completely rewritten the timer and sidereal clock implementation to function on two timer interrupts (RA and DEC) of the Nano. My approach was for the Nano to keep track of sidereal time as an integer count of microsteps and the RA and DEC positions were computed as offsets from this sidereal microstep clock. It allowed the math to be all integer and clock accuracy was still possible with an external PPS used to adjust the RA timer interrupt interval. I then wrote an INDI mount driver that handled all the conversion from RA and DEC position in number of microsteps from the reference sidereal counter which allowed me to use PHD2 and Stellarium.

With the TMC2209, GoTos are ultra quiet as I had implemented a smooth acceleration and deceleration function.
 
It worked well for GoTo but guiding was not very successful. For Goto, I'm reimplementing on a Nano RP2040  because I want the full feature suite of OnStep and I'm not interested in troubleshooting the DEC guiding issues I had.

Any pointers to documentation on the RA,DEC and sidereal timer functions would be welcomed. Otherwise, I'll continue to reverse engineer my comprehension.

Thanks 

Marc


Re: Zhumell Z8 Dobsonian accuracy troubleshooting/showcase #dob #backlash #maxesp3

Burton
 

Alright, so I've done some more reading on here, and found some threads talking about using over 200x magnification and making sure the base is leveled. I had previously been using 80x magnification, so I will try those two things independently and then together to see what works. If someone could confirm that would help or any other tips, I'd really appreciate it!


Re: Skywatcher EQ3-2 BluePill STM32 Goto moves way to much #EQ3

John Petterson
 

Frank,  That information in the FAQ will help sort out the directional movements to get that right, and then to check on the amount of movement.   You should also read the section in the Wiki about the Bluepill and TMC drivers (https://onstep.groups.io/g/main/wiki/6408 and scroll down to stepper drivers), and check the jumpers that you have installed.  Those should set the board up to allow changing the microstep rates.


Re: hello everyone, i have a new question. If I install a powerful servo motor with encoder instead of stepper motor, will the system work? #mount

 

I also want to get a ready plug and play onstep control box with everything the last system.this was sold? and where can i buy


Re: My DIY Friction Drive Mount #maxesp3 #cnc #diy #mount #esp32

johnwashington1978@...
 

I've never seen one first hand but I believe the mesu 2mm shafts are the actual motor shaft at stage one and a simple hardened ground dowel pin at stage 2, both with adjustable larger shaft and bearing behind them to prevent them from being deflected by the friction preload.

I think for the intermediate stages you could use "cheap" 6203 bearing which you intentionally bind the races together and a dowel pin - thus for tiny amounts of investment achieve exceptional levels of precision (and hardness) and only left with the RA wheel to be turned at a workshop.


Re: My DIY Friction Drive Mount #maxesp3 #cnc #diy #mount #esp32

Unluckyluke84
 

Thank you John, I didn't know about Mesu transmission train, it's really interesting, expecially  the 2mm main shaft and the multi-stadium reducer to give a relatively high ratio. 

Some updates: I'm planning to replace the small shaft ball bearings with high quality one (one is a common ball bearing while the other will be a nice self-aligning SKF ball bearing that will replace the  one I installed...that's a poor quality flanged bearing)


Re: MaxSTM v3 through-hole construction tips

johnwashington1978@...
 

Well, JLCPCB arrived in the post this morning and within 30 minutes or so I was up and running - I'm not too keen on the RTC dangling - I'll design up a small 3d printed block that screws between it and the pcb stand off hole - shall post it tomorrow.

Other than that I didn't have any build issues - I sourced the majority of my parts from digikey - I had the leds and diodes already, used an lm7805 vreg and some ebay headers.

If a wally like me can get it together and working, anyone can !!  Big thumbs up!


Re: My DIY Friction Drive Mount #maxesp3 #cnc #diy #mount #esp32

johnwashington1978@...
 



I think the mechanics of the mesu are brilliant - but the cost is very high because of the siderealtechnology controller - if you go stepper or clearpath servo an onstep can handle it.


Re: Occasional error in guide speed - massive overcorrections

GuitsBoy
 

Thanks Howard.

I've downloaded the latest 4.24d, merged with my config and addons, and updated the guide.ino file.  I found that string on lines 164 and 200, and inserted the snippet of code directly above each instance found.   The changes compiled and flashed just fine on my test board.  Unfortunately I'm not sure how to test this other than under the stars, and no good weather on the horizon.  I'll reply once I've had a chance to test.

Thanks again,
-Tony


On 5/27/2021 3:52 PM, Howard Dutton wrote:
On Thu, May 27, 2021 at 11:32 AM, GuitsBoy wrote:
I was under the assumption that any guide speed was retained, be it .25x .5x or 1x.   I use .5x for guiding, but its quite possible that somethings was slewing at 1x.   However, the PHD over-corrections appear to be guiding at something like 4x or 8x, while the calibration was expecting 0.5x.  It does not appear to simply be double.  But I'll certainly keep this in mind.  Thanks.
I agree this seems like a bug.  Not sure if I want to fix it or not, for fear of breaking something in release-4.24 but the following is likely to be a low risk fix (untested.)

In the file Guide.ino add the following line just before enableGuideRate(guideRate); near lines 184 and 200.

if (pulseGuide) { guideTimerCustomRateAxis1=0.0; guideTimerCustomRateAxis2=0.0; activeGuideRate=-1; }

Let me know once you've checked it out.

For some background this is similar to the known issue with guide rates being wrong after spiral searches.  Easier to fix though, I think.

OnStepX has a guide subsystem design that should effectively address these annoying behaviors with custom guide rates.


Re: Skywatcher EQ3-2 BluePill STM32 Goto moves way to much #EQ3

Howard Dutton
 

Follow the second item in the Frequently Asked Questions.


Re: My DIY Friction Drive Mount #maxesp3 #cnc #diy #mount #esp32

johnwashington1978@...
 

Wow, think of beauty made with a homebrew cnc!

I've been aiming to build a mount to replace mine, given the current prices of the higher end skywatcher mounts you could submit the whole job to a machine shop for less than new skywatcher prices.  I work a fair amount with Teknic professionally so I've intended to use their clearpath servos and friction - but its nice to see you've successfully implemented a stepper setup!  Drive torque isn't really a huge issue with a balanced scope - you do however need gearing to keep the stepper RPM up to a sensible speed, which isn't an issue with a servo.

I note mesu mounts appear to use a relatively tiny encoded servo and get a massive gear ratio by having a motor shaft with a small diameter.


Skywatcher EQ3-2 BluePill STM32 Goto moves way to much #EQ3

Frank
 

Hello and gooooood evening from Germany ;-)

First of all, again! Thank you for this project. I have got a Skywatcher 150/750 Newtonian telescope on a EQ3-2 mount. I moved from a MKS Gen L to BluePill STM board. But now I am facing an issue, which I can not explain.

I am currently in testing stage and my mount is pointing to Polaris and so on. I uploaded my site coordinates using an old android phone with OnStep app on it and synced the time.

On my iPhone with different apps like Stellarium or sky safari on it I can control the telescope over wifi. The issue now if I am doing a goto to Kochab or to Capella for testing, the telescope moves to much. For example the degree from Polaris to capella should be for example 40 degree to west. The telescope moves to west but it points down, lets say it moves 200 degree. 

My hardware setup for OnStep is:
BluePill Board
TMC2130 SPI (bigtreetech)

With the MKS Board it was working and I don't have got any clue which I made different.

My XLSX Calculations:


Attached also my config.

Can someone have a look on this and help me, please?

Maybe the

#define AXIS2_DRIVER_MICROSTEPS_GOTO  2 //  

Setting does not work on the bluepill board?

Thank you :-)


Re: Occasional error in guide speed - massive overcorrections

Howard Dutton
 
Edited

On Thu, May 27, 2021 at 11:32 AM, GuitsBoy wrote:
I was under the assumption that any guide speed was retained, be it .25x .5x or 1x.   I use .5x for guiding, but its quite possible that somethings was slewing at 1x.   However, the PHD over-corrections appear to be guiding at something like 4x or 8x, while the calibration was expecting 0.5x.  It does not appear to simply be double.  But I'll certainly keep this in mind.  Thanks.
I agree this seems like a bug.  Not sure if I want to fix it or not, for fear of breaking something in release-4.24 but the following is likely to be a low risk fix (untested.)

In the file Guide.ino add the following line just before enableGuideRate(guideRate); near lines 184 and 200.

if (pulseGuide) { guideTimerCustomRateAxis1=0.0; guideTimerCustomRateAxis2=0.0; activeGuideRate=-1; }

Let me know once you've checked it out.

For some background this is similar to the known issue with guide rates being wrong after spiral searches.  Easier to fix though, I think.

OnStepX has a guide subsystem design that should effectively address these annoying behaviors with custom guide rates (by virtue of its design.)


Re: Occasional error in guide speed - massive overcorrections

Howard Dutton
 

On Thu, May 27, 2021 at 07:48 AM, GuitsBoy wrote:
Also, a quick side question that doesn't warrant it's own thread.  Is there any way to issue a Find/Home command or a Home/Reset command from ASCOM (device hub, poth, or any clients using the ASCOM driver)? 
ASCOM's FindHome() is implemented and this can be done.  I use my own software so not really sure about what others support it.


Re: Occasional error in guide speed - massive overcorrections

Howard Dutton
 
Edited

On Thu, May 27, 2021 at 07:48 AM, GuitsBoy wrote:
I know you don't use APT, but it seems I cannot use a slew rate slower than 2x sidereal, or 0.00835654 degrees/sec.  Anything lower than this results in an error.  I notice that the ASCOM device hub, under capabilities, it shows primary and secondary axis rates as .00833 - 2.00000.  Perhaps this is connected to the reason APT cant move slower than 2x?  Any way to adjust this?
No.

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