Since I aquired an Losmandy G11 mount without any goto provision I decided to create my own solution. I was a bit reluctant to use a Gemini, mainly because of the cost, but also due to the reliability since the servo motors are somewhat prone to failure. I also like to have complete control over the software/firmware so that no "show stopper" issues will ever be a problem for me. Looking around the 'net I saw other goto systems that seemed capable, but either they had needlessly complex hardware or were commercial systems that cost about twice what they should.
OnStep is a computerized goto system, usually for stepper motor equipped mounts though any step/dir interface motor driver (including servo) should work. It was designed, from the beginning, as a more or less general purpose system and provisions were made in the firmware to allow for use on a variety of mounts including Equatorial and Alt/Az (GEM, Fork, Dobsonian, etc.) It uses an LX200 like computer command set with a few extensions to suit hand controller-less operation.
There's a telescope hand controller App for Android (free in the Google Play Store,) an option to control through a website (Smart Web Server,) and a dedicated physical hand controller (Smart Hand Controller.) Or, on a PC there's ASCOM and INDI drivers for control. These options allow you to setup and control OnStep using a wide range of software including my Sky Planetarium, Cartes du Ciel, Stellarium, SkySafari, KStars, PHD2, etc. You can see most of the control possibilities in the diagram below:
Also, please visit my StellarJourney.com site for updates, links to OnStep resources, my other astronomy software, or to see some Images taken with the assistance of my OnStep operated mounts.
If you find OnStep useful and would like to show your appreciation and support please consider making a small monetary donation. This keeps me motivated and helps cover expenses associated with my projects.
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Re: R1
marorte otero
Hello Drew, yesterday I connected everything and my surprise was when I connected the perfect R1 but the problem I do not know if I have done something wrong or it is the R1, when I connect it I hit the East with the jostick and the two engines go crazy from I give the West and they stop, I give the North and the engines run, I give the South either, I don't know if it's the R1 or I'm already lost. All the best
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Re: My Dobson project
kevin
from the 10,666 pulses per degree it also means your minimum movement is 1/ 10666 degrees ,about 6 arcseconds. Again i don't know if that is good enough for you but i have read about people doing astrophotography guiding in the 1/2 arcsecond range so presumably there systems are better than that step size?
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Re: My Dobson project
kevin
When tracking , an eq mount ( bit diferent to a dob unless you are on the equator and the star is overhead) , will be about 24 hours for 360 degrees so 1 degree per 4mins . the pulse rate would then be about 10666/(4mins*60seconds)= 44 pulses per second.
because of your 6:1 belt, one rev of the motor output shaft is actually 60 degees so a slew rate of 1 degree per sec is 1 rev per minute. To move at 1 degree per second 10,600 pulses per second (10.6 KHz). which will depend if your hardare controller can generate it, i think most should do a lot more than that. this is then divided by 32 for each actual motor step (333) then 200 to get the motor rev per second ( 1.66) then 100 for the gearbox to get the output shaft speed of 1 rpm.
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Re: My Dobson project
kevin
sorry I cant read your photo but i suspect you have "double accounted" for your 100 gearbox. the stepper is 200, 32 microsteping the first gearbox is 100 the second gearbox ( listed as worm drive in the config generator) is 6. or you can put in 600 fro the first gearnox and 1 for the wormdrive either way this gererates
#define AXIS1_STEPS_PER_DEGREE 10666.666666666666 // 12800, n. Number of steps per degree: <-Req'd // n = (stepper_steps * micro_steps * overall_gear_reduction)/360.0 and read this as "pulses to the driver per degree" , which seems reasonable to me. depending how you have wired your controller and driver you may be able to change how many microsteps you use when slewing if you can't then just put the same number in.
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Re: R1
That could be your internet browser. I have had trouble with things disappearing and/or not appearing after an edit. The culprit is the browser cache which keeps a copy and reuses it even when you refresh the page.
I don't know what browser you are using but all of them will allow you to clear the cache. Just be sure you are clearing only the cache. Avoid clearing "all" or data or cookies, etc.
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Re: My Dobson project
Tomas de Mora
I have doubts about the correct choice of motors.
Suppose I keep the same pulley ratio
AZ 20-120
ALT 20-240
If I buy a planetary motor with 100: 1 reduction and 0.018 step angle (200 steps) and keep the microsteps in drivers at 32, the total reduction in AZ would be 100: 1 and 6: 1, a total reduction of 600: 1, transferring this data to the OnStep calculator.  Am I doing something wrong? If the data is correct, it is a brutal reduction that far exceeds the specifications of OnStep (61200), I also understand that to achieve 1º / sec of SLEWRATE, the AZ motor must turn at 12000RPM
and the ALT at ¡ 48000 !. In this case, and maintaining that pulley ratio, would a motor with a 10: 1 or 20: 1 reduction be the correct thing to do?
Forgive for my ignorance, I am not an engineer, my profession is in the field of pharmacy and health.
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Re: My Dobson project
kevin
I like the starter ring idea, briliant source of a large gear.
Out of interest years ago in an instument i saw a neat idea to remove backlash but i dont know if it would scale. Basically there were 2 large thin gears on the same shaft and the small gear meshed with both of them ( or other way round). the 2 large gears are either spring loaded if it is a low torque drive or adjusted and screwed. Not the actual ones but i found this page that shows the principle. https://www.kggear.co.jp/en/kg-stock-gears/anti-backlash-spur-gears If the ring gear is thick enough and you have the machining skills maybe the bendix can be turned down and a second one bored out to fit onto it like the ASG type in the link.
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Re: Hardware point to force Park MaxPCB2
Pete,
You can send the LX200, or any else command via WIFI to Onstep to park your mount Alain.
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Re: My Dobson project
barsuk.neo@...
Yes, metal. I used a crown from the starter flywheel and a bendix from the car starter, as well as a stepper motor with a planetary gearbox. But since the tooth of the crown and bendix is large, when the direction of rotation is changed, the backlash will be sampled. The bendix surface is also hardened. I processed it on a lathe, and drilled it with cobalt drills. I got the idea here : https://youtu.be/YLftPAcaMxI и http://www.astronomoamador.com.br/arduino-controle-de-telescopio
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Re: R1
On Fri, Nov 26, 2021 at 12:44 PM, Drew 🔭📷🚴♂️ wrote:
Drew, I thought that I edited the Wiki this morning to place that in -just as I did here- but I guess I was dreamingThen save and exit the IDE. Restart the IDE by clicking the .ino file which allows the following to be done.Thanks, that was needed. since I can't find my Wiki edit??? Getting older by the minute... not much fun ;0)
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Hardware point to force Park MaxPCB2
My observatory is near completion. I have a repurposed Harbor Freight Power Hoist motor driving a rack and pinion roll off roof. I recently added a rain detector to automatically close the roof if rain occurs during remote imaging sessions. This means that I need to remote park my mount. I am using a MaxPCB2 + Teensy 3.6 driving a G11 mount.
Is there a hardware point on the MaxPCB2 that I can use to set the mount to park and unpark based on an incoming signal? As usual, thanks for your help. Pete
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Re: My Dobson project
Tomas de Mora
Thanks Khalid
But for now it is just a project.
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Re: My Dobson project
Tomas de Mora
Impressive, I love what you have built.
The sprockets are metal?
One of the simplest and most compact solutions I have seen.
Exactly I was thinking of dispensing with the belts and directly attacking the ALT and AZ pulleys like you.
It is clear that I must increase the width of the belts, the size of the pulleys and put some motors with more torque.
Thanks
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Re: My Dobson project
barsuk.neo@...
You can estimate the load on the belt teeth as follows: remove the belts from both axles, install the pipe in the rings, now try pressing your finger on the large pulleys. This is especially true for the Alt axis when the pipe is closer to the horizontal position. I believe that the belt will not last long. I would significantly increase the diameter of the driven pulleys/gears and try to increase the gear ratio. You have a small gear ratio (because of this, the mounting axes will move quickly even at the lowest speed), and at large magnifications it will be difficult for you to catch an object in the eyepiece. My automation option is sw dob 8: https://disk.yandex.ru/d/eNAS-KbnuncBdg
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Re: R1
marorte otero
Drew, with your last message it has become clear to me what I was asking, my doubt was that I have seen tutorial videos that the esp8266 connected with the esp32, but you have already made it clear to me in the comment, I am going to solder the sockets to the module and test it. Thank you very much for all your time spent answering me, thank you from the heart. All the best
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Re: R1
On Fri, Nov 26, 2021 at 04:34 PM, marorte otero wrote:
if the esp32 module should be connected together with the esp8266 or only the esp32 is connected?I need a little more info on your setup. Typically, for the BGC (Bluetooth GamePad Controller) the Wemos ESP8266 SWS (SmartWebServer - Wifi) is replaced by the Wemos ESP32. The same SWS firmware is used, but the BLE capability of the ESP32 is used to connect to the BGC.
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Re: R1
marorte otero
Hi Drew, everything turned out great, thank you very much for all the time dedicated to my cause.
Another question I have is if the esp32 module should be connected together with the esp8266 or only the esp32 is connected?
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Re: R1
On Fri, Nov 26, 2021 at 03:29 PM, Ken Hunter wrote:
Then save and exit the IDE. Restart the IDE by clicking the .ino file which allows the following to be done.Thanks, that was needed.
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Re: R1
On Wed, Nov 24, 2021 at 04:33 PM, Drew 🔭📷🚴♂️ wrote:
My edits are BOLD... You will need to have the ESP32 firmware installed. Under the menu File->Preferences open the dialog and add this line in the "Additional "Boards Manager URL's" text box: "http://arduino.esp8266.com/stable/package_esp8266com_index.json,https://dl.espressif.com/dl/package_esp32_index.json" (no quotes). Then save and exit the IDE. Restart the IDE by clicking the .ino file which allows the following to be done. The ESP32 firmware can then be installed from the Hardware Manager in Arduino IDE. Select the "tools" tab, go down to the "Board:" selection. The "Boards manager" will be the top selection. Click it and enter "ESP32" into the search box. Install version 2.0.0 . This is very important! Later version have problems with the serial port that the Wemos uses.
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Re: R1
marorte otero
Hi Drew, thank you very much for the information, right now I am in front of the computer trying to solve the problem
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