Taking the OnStep plunge

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SkyHiker United States of America
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Taking the OnStep plunge

#1

Post by SkyHiker »


I'm not happy with my current goto kit for the G11S. Yesterday I signed on to the OnStep group and put together a bill of materials to make two basic controllers. The first one will be for my G11S, the second one for an Alt/Az system for my Z12 once I get the motorization figured out. The BOM includes a Teensy 4.0, TMC2130 stepper drivers, Arduino/Teensy proto boards, cables and connectors.

It will be as basic as it gets because the Pi with Ekos will provide some functionality as well. A full blown OnStep system can have WiFi, BlueTooth, RJ45 ports, buzzer, ST4, fuse, derotator on special purpose PCBs (some from the printer world) but I don't need that and want to stay as close as possible to a basic Arduino-like system that is easy to debug.

Here are some systems that inspired me to go this route:
https://www.cloudynights.com/topic/5944 ... ?p=8147955
https://www.cloudynights.com/topic/5944 ... ?p=8150552

Ordering two copies of each is also useful to have spare parts in case I mess up. The total costs are $186 for 2 units including a soldering station. I already have 1.8 degree stepper motors from my current kit, although I may have to upgrade them to 0.9 degrees to be determined later. The TMC2130s seem to have amazing micro-stepping abilities so maybe I can get by with them.

It will be a fun project, astronomy is not the only reason why I am interested in this. What I like is that it's all .ino code so no fuss, super easy to prototype, debug and flash. The code seems well structured and configurable to all kinds of hardware. Here's the Wiki for those interested: https://onstep.groups.io/g/main/wiki

I have to wait at least a month for some parts to arrive. If any of you want to share OnStep experiences please chime in.
... Henk. :D Telescopes: GSO 12" Astrograph, "Comet Hunter" MN152, ES ED127CF, ES ED80, WO Redcat51, Z12, AT6RC, Celestron Skymaster 20x80, Mounts and tripod: Losmandy G11S with OnStep, AVX, Tiltall, Cameras: ASI2600MC, ASI2600MM, ASI120 mini, Fuji X-a1, Canon XSi, T6, ELPH 100HS, DIY: OnStep controller, Pi4b/power rig, Afocal adapter, Foldable Dob base, Az/Alt Dob setting circles, Accessories: ZWO 36 mm filter wheel, TV Paracorr 2, Baader MPCC Mk III, ES FF, SSAG, QHY OAG-M, EAF electronic focuser, Plossls, Barlows, Telrad, Laser collimators (Seben LK1, Z12, Howie Glatter), Cheshire, 2 Orion RACIs 8x50, Software: KStars-Ekos, DSS, PHD2, Nebulosity, Photo Gallery, Gimp, CHDK, Computers:Pi4b, 2x running KStars/Ekos, Toshiba Satellite 17", Website:Henk's astro images
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Re: Taking the OnStep plunge

#2

Post by SkyHiker »


It's alive!

This is just a test setup while I'm waiting for the Wemos R31 to arrive. It's a Teensy 4.0 on a Teensy Arduino shield with a CNC v3 board on top, using the standard A4988 drivers. I command it from my Galaxy Tab A via Bluetooth using the OnStep app. Right now it runs in full step because my jumper heads are still in the mail. The motors are my old kit motors, 32 Ncm, 200 steps. Horrible discretization therefore but at least tracking and slewing works. Thus far I only configured the motors, haven't checked into the Teensy's RTC and EEPROM yet. I have to say, it was pretty straightforward.

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... Henk. :D Telescopes: GSO 12" Astrograph, "Comet Hunter" MN152, ES ED127CF, ES ED80, WO Redcat51, Z12, AT6RC, Celestron Skymaster 20x80, Mounts and tripod: Losmandy G11S with OnStep, AVX, Tiltall, Cameras: ASI2600MC, ASI2600MM, ASI120 mini, Fuji X-a1, Canon XSi, T6, ELPH 100HS, DIY: OnStep controller, Pi4b/power rig, Afocal adapter, Foldable Dob base, Az/Alt Dob setting circles, Accessories: ZWO 36 mm filter wheel, TV Paracorr 2, Baader MPCC Mk III, ES FF, SSAG, QHY OAG-M, EAF electronic focuser, Plossls, Barlows, Telrad, Laser collimators (Seben LK1, Z12, Howie Glatter), Cheshire, 2 Orion RACIs 8x50, Software: KStars-Ekos, DSS, PHD2, Nebulosity, Photo Gallery, Gimp, CHDK, Computers:Pi4b, 2x running KStars/Ekos, Toshiba Satellite 17", Website:Henk's astro images
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Re: Taking the OnStep plunge

#3

Post by helicon »


Good luck with the project Henk.
-Michael
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Re: Taking the OnStep plunge

#4

Post by SkyHiker »


I just hooked the Teensy's micro USB port up to the Pi and was able to control the motors through Ekos. As expected, but pleasing nevertheless.

So far everything went quite smooth. Waiting for the Wemos R342 and the TMC2130s in a week or so (and jumper caps, those hopefully by mid October?)
... Henk. :D Telescopes: GSO 12" Astrograph, "Comet Hunter" MN152, ES ED127CF, ES ED80, WO Redcat51, Z12, AT6RC, Celestron Skymaster 20x80, Mounts and tripod: Losmandy G11S with OnStep, AVX, Tiltall, Cameras: ASI2600MC, ASI2600MM, ASI120 mini, Fuji X-a1, Canon XSi, T6, ELPH 100HS, DIY: OnStep controller, Pi4b/power rig, Afocal adapter, Foldable Dob base, Az/Alt Dob setting circles, Accessories: ZWO 36 mm filter wheel, TV Paracorr 2, Baader MPCC Mk III, ES FF, SSAG, QHY OAG-M, EAF electronic focuser, Plossls, Barlows, Telrad, Laser collimators (Seben LK1, Z12, Howie Glatter), Cheshire, 2 Orion RACIs 8x50, Software: KStars-Ekos, DSS, PHD2, Nebulosity, Photo Gallery, Gimp, CHDK, Computers:Pi4b, 2x running KStars/Ekos, Toshiba Satellite 17", Website:Henk's astro images
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Re: Taking the OnStep plunge

#5

Post by SkyHiker »


I mounted everything on the scope and did some rough tests on goto and alignment inside. It seems to be working. I am running the steppers at 16x microstepping. The A4988 drivers that I am currently using are not ideal because they don't support mode switching. This means that slowing is also done in micro step mode, which is rather slow. The TMC3120s that I ordered will fix this. And of course I need to clean up the cabling and build an enclosure around it but here is a picture. The black box to the left is the Pi running Ekos, connected to the OnStep controller.

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20200829_232834.jpg
... Henk. :D Telescopes: GSO 12" Astrograph, "Comet Hunter" MN152, ES ED127CF, ES ED80, WO Redcat51, Z12, AT6RC, Celestron Skymaster 20x80, Mounts and tripod: Losmandy G11S with OnStep, AVX, Tiltall, Cameras: ASI2600MC, ASI2600MM, ASI120 mini, Fuji X-a1, Canon XSi, T6, ELPH 100HS, DIY: OnStep controller, Pi4b/power rig, Afocal adapter, Foldable Dob base, Az/Alt Dob setting circles, Accessories: ZWO 36 mm filter wheel, TV Paracorr 2, Baader MPCC Mk III, ES FF, SSAG, QHY OAG-M, EAF electronic focuser, Plossls, Barlows, Telrad, Laser collimators (Seben LK1, Z12, Howie Glatter), Cheshire, 2 Orion RACIs 8x50, Software: KStars-Ekos, DSS, PHD2, Nebulosity, Photo Gallery, Gimp, CHDK, Computers:Pi4b, 2x running KStars/Ekos, Toshiba Satellite 17", Website:Henk's astro images
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Re: Taking the OnStep plunge

#6

Post by SkyHiker »


The TMC2130s and Wemos-es had apparently arrived yesterday when I checked my mailbox. So, there was work to be done!

I decided to leave the Wemos alone for now because it's a 3.3V device whereas the CNCv3 is built for 5V and can emit too high voltages back into the Wemos unless a resistor is desoldered. Why do that if the Teensy shield works.

The TMC2130s are controlled by SPI so I had to wire 4 connections for both drivers. The hard part was to figure out the pin mapping from Teensy to Arduino shield to CNCv3 shield to TMC2130. Anyway I got it working.

At first it was squealing like a pig. I started writing a message to the OnStep board, then I noticed there was a quiet setting in the configuration. After changing that it was very quiet indeed, very nice!

Very cool. Now I need to wait for the ethernet sockets so I can finish the wiring and build a case around it. Meanwhile I'll try it as is once the Moon gets out of the way.
... Henk. :D Telescopes: GSO 12" Astrograph, "Comet Hunter" MN152, ES ED127CF, ES ED80, WO Redcat51, Z12, AT6RC, Celestron Skymaster 20x80, Mounts and tripod: Losmandy G11S with OnStep, AVX, Tiltall, Cameras: ASI2600MC, ASI2600MM, ASI120 mini, Fuji X-a1, Canon XSi, T6, ELPH 100HS, DIY: OnStep controller, Pi4b/power rig, Afocal adapter, Foldable Dob base, Az/Alt Dob setting circles, Accessories: ZWO 36 mm filter wheel, TV Paracorr 2, Baader MPCC Mk III, ES FF, SSAG, QHY OAG-M, EAF electronic focuser, Plossls, Barlows, Telrad, Laser collimators (Seben LK1, Z12, Howie Glatter), Cheshire, 2 Orion RACIs 8x50, Software: KStars-Ekos, DSS, PHD2, Nebulosity, Photo Gallery, Gimp, CHDK, Computers:Pi4b, 2x running KStars/Ekos, Toshiba Satellite 17", Website:Henk's astro images
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Re: Taking the OnStep plunge

#7

Post by The Happy Parrot »


Very interesting project Henk. Thanks for sharing details and good that you've avoided the release of magic smoke -a specialty of mine- by watching for voltage differences between components.

Curious about the Arduino sketch orchestrating all this. Are you writing it from scratch or is there an open source Github version you can use?
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Re: Taking the OnStep plunge

#8

Post by ARock »


Which brand/version of TMC2130s are you using? Are the SPI pins reversed?

I dont use ONSTEP, but I do use a CNC V3 shield on an Arduino UNO for GoTo on my EXOS Nano EQ. I use the old DRV8825s that I had from my inital perfboard solution.
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Re: Taking the OnStep plunge

#9

Post by SkyHiker »


ARock wrote: Mon Aug 31, 2020 7:02 pm Which brand/version of TMC2130s are you using? Are the SPI pins reversed?
I use the version that has SPI enabled. If you buy the other version you can still manually convert it to SPI enabled but you need to solder tiny parts, which is humanly impossible - only a robot can do that.

I'm not sure what you mean with the SPI pins reversed. As far as I have seen most driver chips are more or less compatible so you can make drop-in replacements. The only thing I know about is if the board is configured for SPI or not.

You may want to check the OnStep Wiki for useful comments.
ARock wrote: Mon Aug 31, 2020 7:02 pm I dont use ONSTEP, but I do use a CNC V3 shield on an Arduino UNO for GoTo on my EXOS Nano EQ. I use the old DRV8825s that I had from my inital perfboard solution.
How cool that you use a CNCv3 shield too. The Arduino Uno may be a bit slow though. For OnStep it doesn't have enough memory, that's why I got a Teensy 4.0 instead and soldered it into an Arduino shield. One gotcha for the CNCv3: The Wemos or my Teensy based board are 3.3V parts so there is one resistor on the CNCv3 that must be de-soldered to protect the chip on the board. See the OnStep Wiki.

OnStep uses its own software SPI implementation good enough to talk to SPI driver chips, so you can use any digital IO pins in the OnStep configuration file. In my case I had to find some pins available then map them from Teensy to Arduino shield to CNCv3 to TMC2130. Then I had to connect the pins on the CNCv3 to the TMC2130 SPI pins by 4 cables per driver.

If you wanted to go the OnStep route, consider MKS Gen-L v2, it has slots for the drivers with SPI pins so all you need to do is put jumper caps on them and plug in the driver. Saves some cables.
... Henk. :D Telescopes: GSO 12" Astrograph, "Comet Hunter" MN152, ES ED127CF, ES ED80, WO Redcat51, Z12, AT6RC, Celestron Skymaster 20x80, Mounts and tripod: Losmandy G11S with OnStep, AVX, Tiltall, Cameras: ASI2600MC, ASI2600MM, ASI120 mini, Fuji X-a1, Canon XSi, T6, ELPH 100HS, DIY: OnStep controller, Pi4b/power rig, Afocal adapter, Foldable Dob base, Az/Alt Dob setting circles, Accessories: ZWO 36 mm filter wheel, TV Paracorr 2, Baader MPCC Mk III, ES FF, SSAG, QHY OAG-M, EAF electronic focuser, Plossls, Barlows, Telrad, Laser collimators (Seben LK1, Z12, Howie Glatter), Cheshire, 2 Orion RACIs 8x50, Software: KStars-Ekos, DSS, PHD2, Nebulosity, Photo Gallery, Gimp, CHDK, Computers:Pi4b, 2x running KStars/Ekos, Toshiba Satellite 17", Website:Henk's astro images
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Re: Taking the OnStep plunge

#10

Post by SkyHiker »


The Happy Parrot wrote: Mon Aug 31, 2020 2:29 pm Very interesting project Henk. Thanks for sharing details and good that you've avoided the release of magic smoke -a specialty of mine- by watching for voltage differences between components.
Thanks actually the Teensy 4.0 is a 3.3 V part too (the 3.1 and 3.2 are 5V) so I still have to de-solder the resistor, as it turns out. So I may as well try this Wemos R32, they are dirt cheap replacements for Arduino Unos with much more capability.
The Happy Parrot wrote: Mon Aug 31, 2020 2:29 pm Curious about the Arduino sketch orchestrating all this. Are you writing it from scratch or is there an open source Github version you can use?
It's all in the OnStep github repository. At the top level there are the .ino files for all high level logic. It has directories for hardware abstraction (HAL), boards and driver chips. The latter are all written in C but it compiles and runs flawlessly.

OnStep has some PCB designs that you can download and order (by one of these PCB on the fly shops), and buy the parts. I opted for COTS boards and am learning the code. Users mostly have to deal with the configuration and maybe modify some pin maps (in my case because I was not using a standard board). These are simple things to do. OnStep has a client app that you can put on your Android for a goto hand controller. Ekos has a driver that implements all needed client features, they show up in tabs for configuration.
... Henk. :D Telescopes: GSO 12" Astrograph, "Comet Hunter" MN152, ES ED127CF, ES ED80, WO Redcat51, Z12, AT6RC, Celestron Skymaster 20x80, Mounts and tripod: Losmandy G11S with OnStep, AVX, Tiltall, Cameras: ASI2600MC, ASI2600MM, ASI120 mini, Fuji X-a1, Canon XSi, T6, ELPH 100HS, DIY: OnStep controller, Pi4b/power rig, Afocal adapter, Foldable Dob base, Az/Alt Dob setting circles, Accessories: ZWO 36 mm filter wheel, TV Paracorr 2, Baader MPCC Mk III, ES FF, SSAG, QHY OAG-M, EAF electronic focuser, Plossls, Barlows, Telrad, Laser collimators (Seben LK1, Z12, Howie Glatter), Cheshire, 2 Orion RACIs 8x50, Software: KStars-Ekos, DSS, PHD2, Nebulosity, Photo Gallery, Gimp, CHDK, Computers:Pi4b, 2x running KStars/Ekos, Toshiba Satellite 17", Website:Henk's astro images
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Re: Taking the OnStep plunge

#11

Post by ARock »


SkyHiker wrote: Mon Aug 31, 2020 8:54 pm
ARock wrote: Mon Aug 31, 2020 7:02 pm Which brand/version of TMC2130s are you using? Are the SPI pins reversed?
I use the version that has SPI enabled. If you buy the other version you can still manually convert it to SPI enabled but you need to solder tiny parts, which is humanly impossible - only a robot can do that.

I'm not sure what you mean with the SPI pins reversed. As far as I have seen most driver chips are more or less compatible so you can make drop-in replacements. The only thing I know about is if the board is configured for SPI or not.

You may want to check the OnStep Wiki for useful comments.

Some of the TMC2130 s have the SPI pins pointing upwards and not down into the socket, so you can add wires to them independent of the shield.

SkyHiker wrote: Mon Aug 31, 2020 8:54 pm
ARock wrote: Mon Aug 31, 2020 7:02 pm I dont use ONSTEP, but I do use a CNC V3 shield on an Arduino UNO for GoTo on my EXOS Nano EQ. I use the old DRV8825s that I had from my inital perfboard solution.
How cool that you use a CNCv3 shield too. The Arduino Uno may be a bit slow though. For OnStep it doesn't have enough memory, that's why I got a Teensy 4.0 instead and soldered it into an Arduino shield. One gotcha for the CNCv3: The Wemos or my Teensy based board are 3.3V parts so there is one resistor on the CNCv3 that must be de-soldered to protect the chip on the board. See the OnStep Wiki.

OnStep uses its own software SPI implementation good enough to talk to SPI driver chips, so you can use any digital IO pins in the OnStep configuration file. In my case I had to find some pins available then map them from Teensy to Arduino shield to CNCv3 to TMC2130. Then I had to connect the pins on the CNCv3 to the TMC2130 SPI pins by 4 cables per driver.

If you wanted to go the OnStep route, consider MKS Gen-L v2, it has slots for the drivers with SPI pins so all you need to do is put jumper caps on them and plug in the driver. Saves some cables.
I started with RA guiding on the setup and then added GoTo. I even bought the MKS Gen-L board to try ONSTEP, but decided to try GoTo on my existing setup which as you say cannot run ONSTEP. SPI is too complicated to use without ONSTEP so I have stayed away from it for now. I am thinking of changing from the DRV8825 to the LV8729 to get the 64 way microstep, but given that I have it all working, I am not very motivated to do it. :)
Last edited by ARock on Mon Aug 31, 2020 9:43 pm, edited 1 time in total.
AR
Scopes: Zhumell Z8, Meade Adventure 80mm, Bushnell 1300x100 Goto Mak.
Mount: ES EXOS Nano EQ Mount, DIY Arduino+Stepper drives.
AP: 50mm guidescope, AR0130 based guidecam, Canon T3i, UHC filter.
EPs: ES82 18,11,6.7mm, Zhumell 30,9mm FJ Ortho 9mm, assorted plossls, Meade 2x S-F Barlow, DGM NPB filter.
Binos: Celestron Skymaster 15x70 (Albott tripod/monopod), Nikon Naturalist 7x35.
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Re: Taking the OnStep plunge

#12

Post by SkyHiker »


ARock wrote: Mon Aug 31, 2020 9:32 pm Some of the TMC2130 s have the SPI pins pointing upwards and not down into the socket, so you can add wires to them independent of the shield.
Yea I have those so I could add the wires easily.
... Henk. :D Telescopes: GSO 12" Astrograph, "Comet Hunter" MN152, ES ED127CF, ES ED80, WO Redcat51, Z12, AT6RC, Celestron Skymaster 20x80, Mounts and tripod: Losmandy G11S with OnStep, AVX, Tiltall, Cameras: ASI2600MC, ASI2600MM, ASI120 mini, Fuji X-a1, Canon XSi, T6, ELPH 100HS, DIY: OnStep controller, Pi4b/power rig, Afocal adapter, Foldable Dob base, Az/Alt Dob setting circles, Accessories: ZWO 36 mm filter wheel, TV Paracorr 2, Baader MPCC Mk III, ES FF, SSAG, QHY OAG-M, EAF electronic focuser, Plossls, Barlows, Telrad, Laser collimators (Seben LK1, Z12, Howie Glatter), Cheshire, 2 Orion RACIs 8x50, Software: KStars-Ekos, DSS, PHD2, Nebulosity, Photo Gallery, Gimp, CHDK, Computers:Pi4b, 2x running KStars/Ekos, Toshiba Satellite 17", Website:Henk's astro images
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Re: Taking the OnStep plunge

#13

Post by The Happy Parrot »


I hope you keep us posted as you pioneer your way through this, Henk. I've been wanting to do something like this for some time.
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Re: Taking the OnStep plunge

#14

Post by yobbo89 »


glad to have a "technerd" onboard . nice going henk.

i've heard that losmandy make solid mounts but are a little outdated in the electronics side, was this the case with you and your mount ?
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Re: Taking the OnStep plunge

#15

Post by SkyHiker »


yobbo89 wrote: Tue Sep 01, 2020 12:52 pm glad to have a "technerd" onboard . nice going henk.

i've heard that losmandy make solid mounts but are a little outdated in the electronics side, was this the case with you and your mount ?
No, the Gemini control system is probably fine, but they charge quite a bit extra for that. If you look at the G11S (tracking, no goto) vs the G11G (Gemini tracking and goto), IIRC the difference was $900 which I thought was extravagant for a bunch of electronics and motors that should not cost much more than the hardware price - it's a commodity IMHO, look at other companies. The price is mainly because it was outsourced I think. I have a mental barrier for overpaying even when I can easily afford it - hard to explain.

I could have gone with the CEM60 for the same price as the Losmandy and have all the electronic gadgetry I need but I want to buy American if I can. And I like DIY challenges, so here I am. I should also say, I like the mechanical design of the Losmandies very much, the tripod is as solid as a pier, the mount is very stable.

Arduinos are not difficult, they made embedded programming so simple, anyone can do it. I bought various parts so I can build 4 systems just in case something breaks or if I have problems with one design vs. the other. Having to wait for shipping could take months, the parts are only $5 each or so. Including wires, soldering gear, all kinds of electronics just-in-case accessories.
... Henk. :D Telescopes: GSO 12" Astrograph, "Comet Hunter" MN152, ES ED127CF, ES ED80, WO Redcat51, Z12, AT6RC, Celestron Skymaster 20x80, Mounts and tripod: Losmandy G11S with OnStep, AVX, Tiltall, Cameras: ASI2600MC, ASI2600MM, ASI120 mini, Fuji X-a1, Canon XSi, T6, ELPH 100HS, DIY: OnStep controller, Pi4b/power rig, Afocal adapter, Foldable Dob base, Az/Alt Dob setting circles, Accessories: ZWO 36 mm filter wheel, TV Paracorr 2, Baader MPCC Mk III, ES FF, SSAG, QHY OAG-M, EAF electronic focuser, Plossls, Barlows, Telrad, Laser collimators (Seben LK1, Z12, Howie Glatter), Cheshire, 2 Orion RACIs 8x50, Software: KStars-Ekos, DSS, PHD2, Nebulosity, Photo Gallery, Gimp, CHDK, Computers:Pi4b, 2x running KStars/Ekos, Toshiba Satellite 17", Website:Henk's astro images
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Re: Taking the OnStep plunge

#16

Post by turboscrew »


SkyHiker wrote: Tue Sep 01, 2020 5:37 pm
yobbo89 wrote: Tue Sep 01, 2020 12:52 pm glad to have a "technerd" onboard . nice going henk.

i've heard that losmandy make solid mounts but are a little outdated in the electronics side, was this the case with you and your mount ?
No, the Gemini control system is probably fine, but they charge quite a bit extra for that. If you look at the G11S (tracking, no goto) vs the G11G (Gemini tracking and goto), IIRC the difference was $900 which I thought was extravagant for a bunch of electronics and motors that should not cost much more than the hardware price - it's a commodity IMHO, look at other companies. The price is mainly because it was outsourced I think. I have a mental barrier for overpaying even when I can easily afford it - hard to explain.

I could have gone with the CEM60 for the same price as the Losmandy and have all the electronic gadgetry I need but I want to buy American if I can. And I like DIY challenges, so here I am. I should also say, I like the mechanical design of the Losmandies very much, the tripod is as solid as a pier, the mount is very stable.

Arduinos are not difficult, they made embedded programming so simple, anyone can do it. I bought various parts so I can build 4 systems just in case something breaks or if I have problems with one design vs. the other. Having to wait for shipping could take months, the parts are only $5 each or so. Including wires, soldering gear, all kinds of electronics just-in-case accessories.
If you like Arduinos, have you considered blue pills? Cheaper and faster, and there is STM32Duino for them. It's basically Arduino core for STM32 architecture. I tested STM32Duino for one type of 433MHz radio card and porting Arduino code was pretty easy.
https://predictabledesigns.com/introduc ... tm32duino/
https://github.com/stm32duino/Arduino_Core_STM32
https://www.stm32duino.com/
- Juha

Senior Embedded SW Designer
Telescope: OrionOptics XV12, Mount: CEM120, Tri-pier 360 and alternative dobson mount.
Grab 'n go: Omegon AC 102/660 on AZ-3 mount
Eyepieces: 26 mm Omegon SWAN 70°, 15 mm TV Plössl, 12.5 mm Baader Morpheus, 10 mm TV Delos, 6 mm Baader Classic Ortho, 5 mm TV DeLite, 4 mm and 3 mm TV Radians
Cameras: ZWO ASI 294MM Pro, Omegon veLOX 178C
OAG: TS-Optics TSOAG09, ZWO EFW 7 x 36 mm, ZWO filter sets: LRGB and Ha/OIII/SII
Explore Scientific HR 2" coma corrector, Meade x3 1.25" Barlow, TV PowerMate 4x 2"
Some filters (#80A, ND-96, ND-09, Astronomik UHC)
Laptop: Acer Enduro Urban N3 semi-rugged, Windows 11
LAT 61° 28' 10.9" N, Bortle 5

I don't suffer from insanity. I'm enjoying every minute of it.

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Re: Taking the OnStep plunge

#17

Post by SkyHiker »


turboscrew wrote: Tue Sep 01, 2020 9:10 pm
SkyHiker wrote: Tue Sep 01, 2020 5:37 pm
yobbo89 wrote: Tue Sep 01, 2020 12:52 pm glad to have a "technerd" onboard . nice going henk.

i've heard that losmandy make solid mounts but are a little outdated in the electronics side, was this the case with you and your mount ?
No, the Gemini control system is probably fine, but they charge quite a bit extra for that. If you look at the G11S (tracking, no goto) vs the G11G (Gemini tracking and goto), IIRC the difference was $900 which I thought was extravagant for a bunch of electronics and motors that should not cost much more than the hardware price - it's a commodity IMHO, look at other companies. The price is mainly because it was outsourced I think. I have a mental barrier for overpaying even when I can easily afford it - hard to explain.

I could have gone with the CEM60 for the same price as the Losmandy and have all the electronic gadgetry I need but I want to buy American if I can. And I like DIY challenges, so here I am. I should also say, I like the mechanical design of the Losmandies very much, the tripod is as solid as a pier, the mount is very stable.

Arduinos are not difficult, they made embedded programming so simple, anyone can do it. I bought various parts so I can build 4 systems just in case something breaks or if I have problems with one design vs. the other. Having to wait for shipping could take months, the parts are only $5 each or so. Including wires, soldering gear, all kinds of electronics just-in-case accessories.
If you like Arduinos, have you considered blue pills? Cheaper and faster, and there is STM32Duino for them. It's basically Arduino core for STM32 architecture. I tested STM32Duino for one type of 433MHz radio card and porting Arduino code was pretty easy.
https://predictabledesigns.com/introduc ... tm32duino/
https://github.com/stm32duino/Arduino_Core_STM32
https://www.stm32duino.com/
That was the first one I considered since the OnStep group has a custom PCB for it. Looking at that product, it required a long list of parts, and there were things on the PCB that I did not need and/or did not like. So for those reasons I went with some COTS parts.

That has nothing to do with the STM32 itself and it may be a fine chip. However some OnStep members have a lot of trouble with them. There are a few threads over 100 messages each about the problems if you want to look. Part of it because there was an assumption that they had 128 KB while they are spec-ed with 64 KB (AFAICT). They found batches that had 128 KB and assumed all of them would be but apparently not, and that is what the discussion is about. A bit silly and it is no reason why the STM32 would not be good as spec-ed.

Anyway I felt more comfortable with widely used parts such as the Teensy and it worked very well for me. Everything works as expected and with cheaper parts that are not as commonly used there are often gotchas here and there.
... Henk. :D Telescopes: GSO 12" Astrograph, "Comet Hunter" MN152, ES ED127CF, ES ED80, WO Redcat51, Z12, AT6RC, Celestron Skymaster 20x80, Mounts and tripod: Losmandy G11S with OnStep, AVX, Tiltall, Cameras: ASI2600MC, ASI2600MM, ASI120 mini, Fuji X-a1, Canon XSi, T6, ELPH 100HS, DIY: OnStep controller, Pi4b/power rig, Afocal adapter, Foldable Dob base, Az/Alt Dob setting circles, Accessories: ZWO 36 mm filter wheel, TV Paracorr 2, Baader MPCC Mk III, ES FF, SSAG, QHY OAG-M, EAF electronic focuser, Plossls, Barlows, Telrad, Laser collimators (Seben LK1, Z12, Howie Glatter), Cheshire, 2 Orion RACIs 8x50, Software: KStars-Ekos, DSS, PHD2, Nebulosity, Photo Gallery, Gimp, CHDK, Computers:Pi4b, 2x running KStars/Ekos, Toshiba Satellite 17", Website:Henk's astro images
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Re: Taking the OnStep plunge

#18

Post by turboscrew »


Yes, the flash size is coded in the device "name". STM32F103C8T6 - C=48 pins, 8=64kB flash, T=LQFP package, 6=temp range -40 .. 85°C. And STM32s are used a lot in embedded industry.
STM32s are 32-bit whereas AVRs are 8.bit. Also, bigger Arduinos have chips with the same ARM core.
- Juha

Senior Embedded SW Designer
Telescope: OrionOptics XV12, Mount: CEM120, Tri-pier 360 and alternative dobson mount.
Grab 'n go: Omegon AC 102/660 on AZ-3 mount
Eyepieces: 26 mm Omegon SWAN 70°, 15 mm TV Plössl, 12.5 mm Baader Morpheus, 10 mm TV Delos, 6 mm Baader Classic Ortho, 5 mm TV DeLite, 4 mm and 3 mm TV Radians
Cameras: ZWO ASI 294MM Pro, Omegon veLOX 178C
OAG: TS-Optics TSOAG09, ZWO EFW 7 x 36 mm, ZWO filter sets: LRGB and Ha/OIII/SII
Explore Scientific HR 2" coma corrector, Meade x3 1.25" Barlow, TV PowerMate 4x 2"
Some filters (#80A, ND-96, ND-09, Astronomik UHC)
Laptop: Acer Enduro Urban N3 semi-rugged, Windows 11
LAT 61° 28' 10.9" N, Bortle 5

I don't suffer from insanity. I'm enjoying every minute of it.

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Re: Taking the OnStep plunge

#19

Post by SkyHiker »


I finally received the Wemos R32 (an Arduino-Uno like board with Wifi, Bluetooth and a ton of memory) and got it working with the CNC v3 shield with SPI and the TMC2130 drivers. This was not so easy as apparently one Wemos was broken.

I ordered two of each, as always, just in case, the shipping time is the most critical not the $0.99 cost of the Wemos for instance. The SPI connection worked through one CNC v3 board but not through the other. I haven't thoroughly debugged it but these hardware problems (presumably) take a lot of time to iron out. SPI is used for mode switching so you can slew at full step and track at 16x micro-step. I have lost my confidence in cheap parts a bit but they are still cheap, oh well just order multiples.

I mounted it on the G11S with the Pi, it's a bit kludgy and does not have a cover yet but it slews at 4 degrees per second and tracks so quietly and smooth I have to look to convince myself that it is working. Now it's a matter of the smoke and fog to go away so I can try it under the stars.
20200907_133620.jpg
... Henk. :D Telescopes: GSO 12" Astrograph, "Comet Hunter" MN152, ES ED127CF, ES ED80, WO Redcat51, Z12, AT6RC, Celestron Skymaster 20x80, Mounts and tripod: Losmandy G11S with OnStep, AVX, Tiltall, Cameras: ASI2600MC, ASI2600MM, ASI120 mini, Fuji X-a1, Canon XSi, T6, ELPH 100HS, DIY: OnStep controller, Pi4b/power rig, Afocal adapter, Foldable Dob base, Az/Alt Dob setting circles, Accessories: ZWO 36 mm filter wheel, TV Paracorr 2, Baader MPCC Mk III, ES FF, SSAG, QHY OAG-M, EAF electronic focuser, Plossls, Barlows, Telrad, Laser collimators (Seben LK1, Z12, Howie Glatter), Cheshire, 2 Orion RACIs 8x50, Software: KStars-Ekos, DSS, PHD2, Nebulosity, Photo Gallery, Gimp, CHDK, Computers:Pi4b, 2x running KStars/Ekos, Toshiba Satellite 17", Website:Henk's astro images
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Re: Taking the OnStep plunge

#20

Post by helicon »


Looks nice Henk. Good thinking on ordering the extra parts.
-Michael
Refractors: ES AR152 f/6.5 Achromat on Twilight II, Celestron 102mm XLT f/9.8 on Celestron Heavy Duty Alt Az mount, KOWA 90mm spotting scope
Binoculars: Celestron SkyMaster 15x70, Bushnell 10x50
Eyepieces: Various, GSO Superview, 9mm Plossl, Celestron 25mm Plossl
Camera: ZWO ASI 120
Naked Eye: Two Eyeballs
Latitude: 48.7229° N
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