Date   

Re: Showcase: Built With OnStep

Pedro Fernandes
 

On Mon, Apr 9, 2018 at 04:31 am, Gintautas Drazdauskas wrote:
Have to fight with excessive backlash.
Has the main wheel and the worm been machined in sequence or not?

Ideally, the two elements have been manufactured with one another forming a selected pair.

It can be a simple matter of adjusting the wheelbase, trying to eliminate the gap as much as possible.

Pedro


Re: One more MiniPCB OnStep

Pedro Fernandes
 

Hi Howard,

I do the following:
1 - Manually set mount to polar alignment position;
2 - Initialize / Park;
3 - At Home (Reset);
4 - Un-park (starts tracking);
5 - I select Bright Stars - I choose Arturus for example;
6 - Goto - Goto starts and before reaching the Arturus, stops and asks Continue>
7 - Select Continue> and restart the Goto that goes far beyond Arturus.
I've tried disconnecting and redoing everything but it seems to keep that position in memory.

Pedro


Re: Showcase: Built With OnStep

Howard Dutton
 

Gintautas, I pulled a copy of what I think is your original post from Alain's reply and re-posted so it's easy to find...

Hi there,
I am Gintautas from Lithuania.
At first I want to say a lot of thanks and to pay obeisance to the Howard, Khalid and everyone who collaborate creating and developing the Onstep project. It is fantastic.
I have followed Howard's "stellarjourney" more than a year. Had tested a while Onstep on Mega2560 with Bluetooth but had hesitate to start building controller because did not have a mount. Now I use a dobson mount on the equatorial platform.
But almost a year ago I was lucky enough to buy a pair of 190 mm diameter 359 teeth worm wheels with worms for a very, very good price. So I had no another choice than to build a mount.
So I have had to get more deeply acquainted with mechanics (I am electronic engineer) and have obtained a lot of new skils and knowledge. I have created a drawings and ordered the parts in a local workshop.
And, of course, I needed a controller. So have built the Onstep controller.
And finally, yesterday evening, was the first field test of the mount and controller. Of course it was just a first test and there are a couple of things to improve or finish. But I am happy it works, motors are capable to drive a load (track and slew). For the test I have used the Alpha branch.
Basic elements are:
OTA is Skywatcher 254/1200
Onstep built on MaxPCB v 1.11,
Teensy 3.6,
ESP8266 ( it is Chinese Ebay stuff, so there is some problems uploading firmware through Teensy, so I use upload via USB/serial adaptor),
DS3231
Drivers for RA/DEC Chinese Ebay TMC2130 (had to modify the boards as per Pedro post https://groups.io/g/onstep/message/1877)
Drivers for the Focusers - DRV8825 (have used them at the first tests for RA and DEC on the table).
Motors for RA/DEC are 17HM15-0904S.
Motor PSU - 24V
Gear ratio motor pulley to worm pulley 1,72413793103448 (15 to 26 teeth T2.5 ), worm wheel 359 teeth.
For now I use "'Stellarium" and "Stellarium scope" for navigation.
The Onstep has started to work from the first software upload and power up.
If there was any problem - it was related to the my mistakes in configuration only (at least till now).
It works using PC and Android either as well as ASCOM drivers.
I hope I will enjoy after I will finish it.
















Re: General information about OnStep functionality

Howard Dutton
 
Edited

On Mon, Apr 9, 2018 at 03:32 am, Peter Dulowsky wrote:
Now, i have a Bresser Exos2 mount i want to add RA drive. Since the stock solution is over 100 euros i think i would be better off if i take OnStep route. I spent this weekend evenings reading through this board and wiki but still am not clear about few things.

I am currently considering using Teensy 3.2 + TMC2100 (2130?) + Wifi on a protoboard powered from 12V gel battery.
The cost of a MiniPCB (from EasyEDA) is well worth the hassle it saves but either way.  The TMC2130 is the best stepper driver for most users.  The TMC2100 can work just as well in some cases but offers no advantage over the TMC2130 other than simplifying the wiring a bit (and that doesn't matter in the least if you build a MiniPCB.)

I am not quite clear about what motors, pulleys, belts and other mechanical bits i will need.
It's basically an EQ5 mount and many have converted these to OnStep.  Most use NEMA17 400 step motors (about 0.8 or 0.9A) and a 2.5:1 or 3:1 timing belt/pulleys to the worm for each axis.  There are photos around and more details in the "Construction" page of the Wiki.

I can imagine two scenarios:

1. OnStep just for RA tracking (without goto)
I imagine i start with polar aligned mount, OTA in home position. What happens when i power on OnStep?
Will it start tracking (driving RA stepper) without any input from Android App (or smilar control input)?
Not normally but there's an option (I don't recommend.)  #define AUTOSTART_TRACKING_ON

Can I wire up 4 switches to ST4 interface to get slow motion control?
Yes.  Read Config.xxx.h in OnStep, there is support for sequences of button presses for changing the guide rate, etc. too.

2. OnStep in full goto mode with Skysafari
I am not quite clear how the alignment process works. 
So, i guess polar alignment of the mount will be the first step. Then i point the OTA to home position (arrow marks on the mount aligned).
Yes.

What next? Do I need to use your android app for star alignment or can i start SkySafari and do the alignment there?
Normally the Android App unless a PC is attached then my Sky Planetarium (SP) can do the same [and also OnStep's WiFi option website and any planetarium program.]  There are certain alignment limitations, align stars for a two or three star align need to be in certain areas' of the sky.  The App lists suitable alignment stars, SP shows areas' on the map to choose a star from [or if using the website you need to know the suitable align locations for each step in the process.]  SP also has a more advanced alignment method (n-star) called Goto Assist that uses an entirely different method.

The nearest thing to doing an alignment of OnStep with just SkySafari is doing a Sync (which is a 1-star alignment.)

Is the alignment data stored in OnStep non volatile memory?
What happens if the control app looses connection to the mount or the mount power is recycled? Will the alignment be lost?
Control App loosing connection for a bit doesn't affect alignment.  Alignment terms (geometric mount model) are stored in non-volatile memory when parking is used otherwise they're lost when you power off.

I cannot see RTC in the circuit. How does OnStep get time? Is that from the control App?
Yes from the whatever device you're controlling with.  The DS3231 (I2C RTC) and DS3234 (SPI RTC) are supported too but not on a MiniPCB (doesn't have the spare pins.)  Well, actually it could be done with the MiniPCB but you'd loose the ST4 port.

And what about the observing location? 
As above, stored in NV memory.  The Android App can pull location from GPS to fill "site info" for upload.

I had ETX goto scope and i remember it was very important to "train" the drives to get correct amount of backlash compensation. Is something like that supported by OnStep?
Backlash compensation is supported, but there is no "setup routine" so you have to work out the settings.

What king of noise can one expect when tracking? Is it going to be quiter that ETX?
Depends on the drive design, stepper motors, mounting/resonance, etc... and drivers.  The TMC2130 is stealthChop on my G11 (360:1 overall ratio, 400 step NEMA17) range from silent during tracking to super quiet during slews (start of slew I have to be careful since it's easy to not realize the mount is moving.)  My old LXD75 made way way more noise.  But then you can't always use stealthChop for slews (since spreadCycle is better for reaching faster step rates.)  With other drivers or in spreadCycle noise even during tracking (chopper/pwm) can be quite annoying or not present at all.

Is OnStep able to detect a collision of the mount with something hard like tripod legs? Will it switch the motors off?
Not from the stepper motors/drivers.  OnStep has software limits though (overhead, horizon, meridian, under pole, etc.)  It also has a limit switch input (for switches on the mount and/or a "panic button".)  OnStep does NOT instantly stop the stepper motors read Config.xxx.h and the Wiki (first time setup section.)

Can OnStep Wifi join existing home network? 

Yes.

We are just scratching the surface here... If you decide to build an OnStep take some time to read through the Wiki and OnStep's Config.MiniPCB.h (and possibly Pins.MiniPCB.h)  I know the Wiki will take an evening but it can really help to avoid problems.



Re: Configuration help

Howard Dutton
 
Edited

On Mon, Apr 9, 2018 at 04:40 am, <ordepoit@...> wrote:
It is easy to reverse the pins if you do not find TMC2130 v1.1 with the pins in the position you want.
"Easy" depends on experience.  I call soldering in the pins on a Watterot TMC2130 easiest so they get the recommendation [except for the RAMPS1.4/Mega2560 where the FYSETC TMC2130 v1.1 is ideal.]  The Watterot stuff is high quality and has schematics available too so it's hard not to like them.

If you can't obtain the Watterot OEM modules affordably then you do what you have to. :)


Re: Configuration help

Howard Dutton
 

On Mon, Apr 9, 2018 at 04:00 am, SurfaceCleanerZ wrote:
And which ones do you recommend for a MaxPCB?
I recommend getting the Watterot (Digikey, Filistruder) ones.

I've ordered the Fystec v1.1 also. You write in the BOM, that they'll fit, so I bought them.
Not sure where you saw that but my BOM on EasyEDA simply lists a "GENERIC STEPPER MOTOR DRIVER CARRIER".

The Watterott ones are at the wrong voltage, that is what I read there.
Again, no idea where you got that from.  There is only a Watterot 5V TMC2100 that won't work.


Re: Configuration help

Pedro Fernandes
 

On Mon, Apr 9, 2018 at 04:00 am, SurfaceCleanerZ wrote:
But they seem to come with SPI pins soldered in facing UP (from my brief search of ebay) which for a MiniPCB or MaxPCB isn't ideal.
It is easy to reverse the pins if you do not find TMC2130 v1.1 with the pins in the position you want.
Pedro


Re: Showcase: Built With OnStep

Gintautas Drazdauskas
 

Well, 
I have made a try to remove some photos added by accident and it seems the whole post was removed. Or is it redirected to any other place?
Thanks for good words.
Have to fight with excessive backlash. I made a spring loaded warm and it is not very good. Will make fixed probably.

Gintautas


Re: Configuration help

SurfaceCleanerZ
 

Hello, 
And which ones do you recommend for a MaxPCB? I've ordered the Fystec v1.1 also. You write in the BOM, that they'll fit, so I bought them. The Watterott ones are at the wrong voltage, that is what I read there. 
Changing the pins to the other side is not possible, right? 

Is that wrong? 

Regards  Stefan
Gesendet mit meinem HTC One

----- Reply message -----
Von: "Howard Dutton" <hjd1964@...>
An: <onstep@groups.io>
Betreff: [onstep] Configuration help
Datum: Mo., Apr. 9, 2018 12:33

But they seem to come with SPI pins soldered in facing UP (from my brief search of ebay) which for a MiniPCB or MaxPCB isn't ideal.  For the RAMPS1.4/Mega2560 it's great.


Re: Configuration help

Howard Dutton
 

But they seem to come with SPI pins soldered in facing UP (from my brief search of ebay) which for a MiniPCB or MaxPCB isn't ideal.  For the RAMPS1.4/Mega2560 it's great.


General information about OnStep functionality

Peter Dulowsky <peter.dulowsky@...>
 

Hello Howard,
i came across your project last Friday. I am really impressed! Well done and thank you for sharing it with us. Being an electronics engineer i really appreciate how much time and effort you saved the others.

Now, i have a Bresser Exos2 mount i want to add RA drive. Since the stock solution is over 100 euros i think i would be better off if i take OnStep route. I spent this weekend evenings reading through this board and wiki but still am not clear about few things.

I am currently considering using Teensy 3.2 + TMC2100 (2130?) + Wifi on a protoboard powered from 12V gel battery. I am not quite clear about what motors, pulleys, belts and other mechanical bits i will need.

I can imagine two scenarios:

1. OnStep just for RA tracking (without goto)
I imagine i start with polar aligned mount, OTA in home position. What happens when i power on OnStep?
Will it start tracking (driving RA stepper) without any input from Android App (or smilar control input)?
Can I wire up 4 switches to ST4 interface to get slow motion control?

2. OnStep in full goto mode with Skysafari
I am not quite clear how the alignment process works. 
So, i guess polar alignment of the mount will be the first step. Then i point the OTA to home position (arrow marks on the mount aligned).

What next? Do I need to use your android app for star alignment or can i start SkySafari and do the alignment there?
Is the alignment data stored in OnStep non volatile memory? What happens if the control app looses connection to the mount or the mount power is recycled? Will the alignment be lost?

I cannot see RTC in the circuit. How does OnStep get time? Is that from the control App? And what about the observing location? 

I had ETX goto scope and i remember it was very important to "train" the drives to get correct amount of backlash compensation. Is something like that supported by OnStep?

What king of noise can one expect when tracking? Is it going to be quiter that ETX?

Is OnStep able to detect a collision of the mount with something hard like tripod legs? Will it switch the motors off?

Can OnStep Wifi join existing home network? 

Peter



Re: Showcase: Built With OnStep

Pedro Fernandes
 

Hi Gintautas,

I'm impressed with this mount diy.

With this mount you will get fantastic guiding accuracy.

I'm also looking for two sets of gears at fair prices, but it's very hard to find.

Congratulations on your courage to develop such a project.

Congratulations to putting this telescope in station with all the rigor that it imposes.

Pedro


Re: Configuration help

Pedro Fernandes
 

Hi azcharlie,
Don't forget you have the Fysetec TMC2130 v.1.1 that is prepared to SPI mode.
Pedro 


Re: Showcase: Built With OnStep

alain
 

Hi Gintautas,


very nice work!

I like the solution for the gear housing, cheap, light and easily accessible.

I am planing to make a fixed station also and your work gives me some ideas about on how to realize the concrete pier.


Regards



Le 08/04/2018 à 22:21, Gintautas Drazdauskas a écrit :

Hi there,
I am Gintautas from Lithuania.
At first I want to say a lot of thanks and to pay obeisance to the Howard, Khalid and everyone who collaborate creating and developing the Onstep project. It is fantastic.
I have followed Howard's "stellarjourney" more than a year. Had tested a while Onstep on Mega2560 with Bluetooth but had hesitate to start building controller because did not have a mount. Now I use a dobson mount on the equatorial platform.
But almost a year ago I was lucky enough to buy a pair of 190 mm diameter 359 teeth worm wheels with worms for a very, very good price. So I had no another choice than to build a mount.
So I have had to get more deeply acquainted with mechanics (I am electronic engineer) and have obtained a lot of new skils and knowledge. I have created a drawings and ordered the parts in a local workshop.
And, of course, I needed a controller. So have built the Onstep controller.
And finally, yesterday evening, was the first field test of the mount and controller. Of course it was just a first test and there are a couple of things to improve or finish. But I am happy it works, motors are capable to drive a load (track and slew). For the test I have used the Alpha branch.
Basic elements are:
OTA is Skywatcher 254/1200
Onstep built on MaxPCB v 1.11,
Teensy 3.6,
ESP8266 ( it is Chinese Ebay stuff, so there is some problems uploading firmware through Teensy, so I use upload via USB/serial adaptor),
DS3231
Drivers for RA/DEC Chinese Ebay TMC2130 (had to modify the boards as per Pedro post https://groups.io/g/onstep/message/1877)
Drivers for the Focusers - DRV8825 (have used them at the first tests for RA and DEC on the table).
Motors for RA/DEC are 17HM15-0904S.
Motor PSU - 24V
Gear ratio motor pulley to worm pulley 1,72413793103448 (15 to 26 teeth T2.5 ), worm wheel 359 teeth.
For now I use "'Stellarium" and "Stellarium scope" for navigation.
The Onstep has started to work from the first software upload and power up.
If there was any problem - it was related to the my mistakes in configuration only (at least till now).
It works using PC and Android either as well as ASCOM drivers.
I hope I will enjoy after I will finish it.

















Re: Sure it will work on a G42 ?

Howard Dutton
 
Edited

On Sun, Apr 8, 2018 at 01:13 pm, Jonathan Durand wrote:
I have received all the parts to make the miniPCB for my G42 with tmc2130 drivers. 
I have noticed i don't have 2k resistor, but 2.2k instead, and i don't have 8.2k resistors but only 10k. Is it an issue if it's not exactly the same resistors ? 
That is ok.

My second question is why the pins on the miniPCB for the HC05/06 module don't correspond to the module itself ? (the pins from the top to the bottow is GND CTS VCC TX RX RTS, when on the module it's STATE, TX RX , GND, VCC ?)
Not all HC05/06 modules on eBay are the same.  You have to find a module that matches. [or jumper it in]

And my last question : is it possible to use a miniPCB for two mounts ? Is it possible to change the configuration easily ? I am trying also to mod an EQ3-2 (belt, better motors resolution etc...)
You need to change configuration file and upload.  So that depends on your definition of "easily".


Re: Sure it will work on a G42 ?

Jonathan Durand
 

Hello all, 

I have received all the parts to make the miniPCB for my G42 with tmc2130 drivers. 
I have noticed i don't have 2k resistor, but 2.2k instead, and i don't have 8.2k resistors but only 10k. Is it an issue if it's not exactly the same resistors ? 

My second question is why the pins on the miniPCB for the HC05/06 module don't correspond to the module itself ? (the pins from the top to the bottow is GND CTS VCC TX RX RTS, when on the module it's STATE, TX RX , GND, VCC ?)

And my last question : is it possible to use a miniPCB for two mounts ? Is it possible to change the configuration easily ? I am trying also to mod an EQ3-2 (belt, better motors resolution etc...)

Thank you !


Re: Configuration help

 


Sorry to say I may have ruined the module.  Looks like I got solder on some of the fine leads coming from the chip.  The module no longer seems to works.   $8 down the drain.    )-:    Best for me to wait until the A4988's get here.
 
Rick
 
On Sun, 08 Apr 2018 11:48:19 -0700 ordepoit@... writes:

It's not easy, but with some patience and skill it's worth it.
Good luck.
Pedro
 



Re: Configuration help

 


I have to get an exacto knife.  I might need a finer solder iron tip, also..
 
 
On Sun, 08 Apr 2018 11:48:19 -0700 ordepoit@... writes:

It's not easy, but with some patience and skill it's worth it.
Good luck.
Pedro
 



Re: Configuration help

 


There seems to be a small black resistor?  between the two contacts.  Can't seem to cut it. 
 
On Sun, 08 Apr 2018 10:25:11 -0700 ordepoit@... writes:

Hi azcharlie,
You have to make this in the image.

Pedro
 



Re: Configuration help

Pedro Fernandes
 

It's not easy, but with some patience and skill it's worth it.
Good luck.
Pedro