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MattT
26-09-2015, 09:27 AM
I am in the process of building a 2" shaft pillow block mount. Building the mechanical parts to the mount is no problem but electronics is a mystery to me.

So where to start with understanding this subject. Any books/sites that are good for understanding how to read a circuit diagram, I guess is the sort of thing I'm after.

Pictured is a 10" 359 tooth Byers drive that will be the RA gear for the mount. I have a 12V stepper motor with it. What do I need to get this motor powered up to track. It comes with 'instructions' pictured. My vague understanding is supply 12V power and it will do its stuff....correct :help:

Matt

peter_4059
26-09-2015, 11:10 AM
Matt,

I think you are going to need a stepper motor controller. Have a look at this site as this controller is already set up for astro and will interface to astro software through ascom:
http://www.astroeq.co.uk/tutorials.php

AndrewJ
26-09-2015, 03:35 PM
Gday Matt
Do you have a better piccy of the motor and its
markings ( or a clear transcription ).
Looks like its a 6 wire stepper in which case a dedicated controller is required to run it. Lots of available choices there but more info reqd on what model it is.

Andrew

MattT
26-09-2015, 03:51 PM
Hi Andrew,

It's a Hurst motor Model ABS, 12VDC, 4 1/2 W.
6 wires that are black, red,white, blue, black and white stripe, blue and white stripe.
Looks exactly like the Hurst Losmandy steppers that I have on the Gaunt mount.

Matt

Edit: it is exactly the same model as the Losmandy stepper.

AndrewJ
26-09-2015, 06:07 PM
Gday Matt
I meant the stuff next to the part number etc
Those nos give you access to the internal resistance details and gear reductions, all of which you need to size the current capacity of the driver and the reqd stepping rate.

Andrew

MattT
27-09-2015, 08:15 AM
Hi Andrew,

Other numbers are P/N 3008-002
Below that Red 150 3497

Will take a photo if that is better.

Peter thanks for link, looks good.

AndrewJ
27-09-2015, 09:05 AM
Gday Matt

Ahh excellent.
When you mentioned it was the same as the Losmandy
i couldnt find any refs to an "ABS" model motor
Most talked of "CA" types

For the ABS types, the following link gives all the details
http://www.hurst-motors.com/asabsgeared.html

but based on it being used by the losmandy,
could you just get an old losmandy Hbx etc to drive it???
( Edit. Hmm, perhaps not, as it looks like the losmandy
controller uses a crystal, so will be fixed for the
losmandy wormwheel tooth count, and the G11 uses 360
whereas yr gear is 359 )

Found this interesting thread on driving the Hursts
http://www.science-bbs.com/17-astro-amateur/99edb2fd4a67a19d-2.htm


Andrew

MattT
27-09-2015, 01:24 PM
Thanks Andrew.
I forgot to mention that there is a gear reduction on the worm and stepper motor. My quick count gives 20 on the motor and 60 on the worm gear giving a 3:1.
The Losmandy steppers go straight to the worm with no reduction so I don't think the Losmandy drive will work.
I think a trip to Jaycar is in order for a 6 pin RJ11 plug. I'll take the motor and instructions along. The guys in my local are pretty helpful...going to ask what to do with all this on CN and see what turns up.
Ed sells these with a 110v synchronous motor which I think is just plug it in and it works. Ed reccomended a 12V for me in Oz (I rang him up) and I hoped it would be plug and play but it seems not.

Might be making a phone call to Ed Byers again....

AndrewJ
27-09-2015, 01:54 PM
Gday Matt

You currently have a stepper, so will need a stepper driver of some sort to run it. These can be made to run at any speed you want ( if the motor is capoable of it ) using a PIC type driver.
The main thing is to see how fast it is going to need to run
ie the motor you list has a 150:1 reduction gearbox built in already
so with a 3:1 reduction on top of that, you have a 450:1 reduction driving a 360 tooth wormwheel, so its not going to go real fast at the output axle :-)
Hurst do sell different motors that you just apply voltage to and they run at a set speed, but they are a different model type.
IIRC, the early Meades used these, and you needed to buy a specific version, as they were pre wired to go CW or CCW at a set speed.

Andrew

MattT
28-09-2015, 11:03 AM
Currently reading up on steppers for telescope control...another learning curve. No doubt it will become clear as I go along.

:thanx:

MattT
30-09-2015, 02:31 PM
Now I'm getting somewhere I think. Have found AWRtechnologies in the UK which has what I want ...but at a price. Will put in a link when I'm at my computer. http://www.awrtech.co.uk/ih/ih_spec.htm

As I mentioned earlier I have an EQ6 board and simple hand control. The EQ6 has 180 teeth. If I put a 2:1 reduction gear set between my stepper and worm gears that should be close to tracking should it not? Thinking out loud here. As an edit I just thought there are gears on the EQ6 steppers so will have to take those into account too.

Thoughts on this approach?

AndrewJ
30-09-2015, 03:11 PM
Gday Matt

The EQ6Pro has a 1.8deg stepper ( microstepped at 64x ) driving a 12-47 reduction belt, so it immediately becomes a problem.
You could always use EQMod to drive it, as you can configure that any way you want, but not sure if your motor is suitable for microstepping.
Also, your stepper already has a 150:1 gearbox built into it, and you mentioned having a 3:1 drive between worm and motor.
With a stepper, you need to work out the steps per arcsec ratio when comparing controllers, you cant just look at the wormwheel toothcount.

Andrew

MattT
30-09-2015, 06:05 PM
Thanks Andrew....back to the electronics drawing board.

GC - South Aus
30-09-2015, 06:34 PM
G'day Matt

Have you thought of or seen Mel Bartels work on stepper controllers and software for telescopes?

Here is a link for the controller:
http://www.bbastrodesigns.com/StepperSystem.html

You can also use different software (i.e. Scope, Scope II, Guide-Project Pluto), this includes controller software which can also interface with planetarium programs:
https://github.com/garlick/bartels-scope
http://www.gototelescopes.com/eq.htm
http://www.projectpluto.com/scope.htm
http://www.bbastrodesigns.com/operate_interfacing.html

Other information/links:
http://www.bbastrodesigns.com/BBAstroDesigns.html

Example others controller system (gives you an idea):
http://www.astromart.com/classifieds/details.asp?classified_id=597808
http://www.pmdo.com/tele2.htm

I don't know if this is of any use to you or if you are already aware of this. But I thought it may give you some ideas on controller boxes and potential software to operate it.

Cheers & Good Luck

Gav

OzEclipse
30-09-2015, 08:34 PM
Hi Matt,

Jaycar used to sell a stepper controller kit. I think it is discontinued. I used it in one of my portable solar eclipse mount motor controls. It's only for unipolar stepper motors.


There are many off the shelf printed circuit boards available on ebay that have everything you need. These are made in China and cost $1-$5 each. You only need a few of these -

Regulated POWER SUPPLY
http://www.ebay.com/itm/DC-DC-Buck-Step-Down-Converter-Module-LM2596-Voltage-Regulator-Led-Voltmeter-/160995621268?hash=item257c163994

PULSE GENERATOR sets the base clock speed for the motor
http://www.ebay.com/itm/NE555-adjustable-frequency-pulse-generator-module-For-Arduino-Smart-Car-/310565377052?hash=item484f23941c
STEPPER DRIVER


http://www.schmalzhaus.com/EasyDriver/


This one allows microstepping, forward reverse, full,1/2, 1/4, 1/8 times microstepping selectable and should drive your motor without an intermediate driver. The driver cards fully populated with components can be purchased very reasonably from sparkfun who support the designer to produce more of this stuff. You can also buy ripoff versions of this board on ebay for a few dollars.

This boards takes a simple pulse generator input or can be controlled from a computer via usb. It is handy to be able to run a drive without having to have a computer attached.

cheers



Joe

MattT
30-09-2015, 08:47 PM
Ta Gav and Joe. I have seen Mel Bartels site but really don't want to spend that kinda cash. Same goes for the AWRtech parts. Tomorrow I will get into my local Jaycar and see what they have.

Have also been told this will work....http://www.alltronics.com/mas_assets/acrobat/97K004.pdf

An email to Ed Byers is in order too. I have a 3:1 gear reduction on the stepper and worm...most gears are 4:1 which would make sense, wonder if this is an error.

My ideal is a simple handset with slew controls....no computers in sight....except encoders and Argo Navis.

OzEclipse
30-09-2015, 09:27 PM
Matt,

That's exactly what I have described. Completely standalone. You can build it for about $25 - $50 in parts depending where you shop. Jaycar don't have anything that will drive that Hurst motor. Set the timer to drive siderial at 1/8 microstep, then slew at 1x gives you 8x slew speed.

My lightweight mount has to pack into a suitcase and fly around the world so the controller is completely stand alone. My lightweight mount is controlled by the old discontinued Jaycar stepper controller. But I am going to build a new control circuit based on the same circuit as I have described here with pulse generator and easy stepper controller. The power supply, easy stepper card & pulse gen cards are so small, I can build them into the housing of my mount and eliminate the whole controller box.

If your circuit is driven by a pulse generator, you can adjust the frequency to any speed you need. Then 3:1 / 4:1 ceases to matter.

If you go down this path, I can give you some info how to wire it up to slew etc.

The alltronics circuit is an unipolar stepper control similar to the old Jaycar one. The Hurst stepper motor you have is a bipolar and needs a different type of drive circuit. I am not sure the Alltronics driver will drive the Hurst motor.

cheers

Joe

GC - South Aus
01-10-2015, 04:03 AM
G'day Matt

That is pretty much what I have sent you as well.

The first link is how to make and what is needed (DIY). All up the parts may reach around $50 or so. The instructions and parts list is for the controller and hand control unit.

The software is optional and the 'scope' software can now be downloaded for free. From links within the website.

The other links are just information or examples. Yes bbsastrodesigns will give you a custom built option if you wish and at a price. But there is enough info there for your own DIY project.

Cheers

Gav

AndrewJ
01-10-2015, 05:48 AM
As per before, you still need to find the pulse rate the motor will be required to run at to give sidereal tracking with the current gearing. ie you may need to change the gearing between motor and worm to enable the motor to operate correctly over the range you want ( if you want to microstep etc ).

Andrew

MattT
01-10-2015, 01:24 PM
Thanks Gav, Joe and Andrew. This is going to take a bit of time for me to understand what I need…working for a living gets in the way of ATMing…will get there eventually :D

DIY is definitely my preferred way. Gav a dumb question if I may…are the Bartels parts all easily available to buy?

to be continued….

GC - South Aus
01-10-2015, 04:51 PM
G'day Matt

While I am not 100% sure, I wouldn't see why not.
From memory there is a list of components at the bottom of the web page. Perhaps print it off next check with Jaycar either online or in person.

There is always eBay too!

Sorry that is about the extent of my knowledge, just wanted to try and point you in a direction. My previous mount came with the controller already built, but it was this exact system and I used the scope program with the Argo Navis system.

Cheers

Gav

AlexN
01-10-2015, 05:31 PM
I have a project in the pipeline that requires me to build a mount and I was considering byers gear/worm for RA drive and something simple like belt driven Dec.

I will watch this thread with much interest and anticipation.

AlexN
01-10-2015, 05:32 PM
As Peter mentioned too. The astroeq Page is worth looking into.

MattT
01-10-2015, 09:32 PM
Thanks Gav I'll look into it.

Alex I'm building a pillow block mount with 2" precision SS shafts. The Dec axis will be a tangent arm as it's simple to build. The Byers drive is amazing. Ed Byers has retired once already and with extra import taxes coming soon I'd say get one sooner than later

Matt

AlexN
01-10-2015, 10:47 PM
This is what I'm hoping to build something like. I'm not fussed on super accurate tracking for long exposure photography. This is intended to carry a big heavy scope with a long focal length for planetary imaging and observation. The only reason I'm looking to build one is because buying a mount for a scope as heavy as this will be is very cost restrictive.

MattT
02-10-2015, 06:20 PM
Seans work is really good.

My mount will cost around $3K to build and I'm building it to take an 8" f10-12 refractor...maybe I mihght get a 9" f15 Istar achro....a long way off in the taxable future :lol:

Here is what I would like to knock up....and what I have so far if you haven't already seen it in CN.

AlexN
02-10-2015, 08:21 PM
I'm building a 12.5" f25 dall kirkham. As I mentioned, planetary imaging only. Just tossing up between a gem and a horseshoe. Your mount looks beautiful thus far.

GC - South Aus
03-10-2015, 05:53 AM
G'day Alex and Matt

Those monster mounts look beauties! :eyepop:

I would love to be able to build something like these.

Matt, other than the pic did you have any plans for your build?

What do you think the max load capacity on something like these would be?

Also, the loop things which hold the bearing (I am assuming) and the shaft on both axis. What are they exactly, are they pre-fabricated/made or something you have to make yourself?

I am not that technically minded, but making something that could last a life time rather than waiting for a great deal on a G11 or NEQ6, and then tinkering with it may be a better option.

You have sparked my imagination, probably not a good thing. :lol:

Looking forward to hearing from you!

Cheers

Gav

MattT
03-10-2015, 08:10 AM
Hi Gav,
I will have to start a thread about the 2" pillow block build. It's one of those things that is going to take a couple of years :eyepop:

The RA scetion is all wrong and is in re-build mode, so all I have so far is the Dec axis.

The loop things are the pillow block bearings from ebay. Cost abot $35 each from Bolton Bearings in the UK. Lots of choices out there.

12x160mm Aluminium plate, SF QD Bushes with a straight 50mm bore and a pair of 50 x500mm Precision Stainless steel shafts. Lots of machine screws.

Weight capacity? No idea but 40+kgs pretty easily I would hope, much more than I would ever put on top of it.

The electrics for the RA gear is my real Achilles heal. You guys have helped hugely with that.

MattT
03-10-2015, 08:30 AM
A couple of questions for astroeq and eqmod users, or anyone who knows.

The astroeq unit needs a computer with eqmod to slew about, is that right?

Does eqmod work with apple computers?

OzEclipse
03-10-2015, 10:46 AM
Matt,
In an earlier post I wrote:-
I made a mistake and misread something on the Hurst site. The Hurst motor you have is unipolar not bipolar. There are many online tutorials that explain the difference between the two types in detail.

A bipolar driver can run any unipolar or bipolar motor.

However a unipolar driver can't drive a bipolar motor.

The Alltronics unipolar driver should drive the Hurst motor.


joe

AlexN
03-10-2015, 11:09 AM
Matt, astroeq and eqmod require a computer to operate.

To my knowledge it is pc only, not mac.

If you only have a mac laptop, I would recommend installing vmware and creating a virtual computer with windows installed in it. This way you run your mac as normal, and when you want to use your mount you fire up vmware, start the virtual computer and operate the telescope through that. It's essentially a computer within a computer.

I'm not sure ofany off the shelf way to drive your mount without a laptop unless you plan on getting the gear ratio absolutely perfect (clock drive sort of thing)

With the computer connected, so long as you know the gear ratios, the computer will compensate.

With eqmod and my heq5, I have fitted a belt drive kit which gives me the exact same ratio as the standard spur gears did. I changed the pulley on the RA worm to give higher resolution. I simply told eqmod that instead of the standard 4:1 gearing ratio in RA it has a 6:1 ratio. Eqmod now tracks at the right speed for the new ratio.

AndrewJ
03-10-2015, 12:40 PM
Gday Alex

Depending on how much flexibility you want, the basic drive would be relatively off the shelf.
There are many std Stepper driver units, that can handle the power to the motor itself, as well as the driving logic. These need to be driven, and the most flexible way is to use some form of PIC microprocessor. The PICAXE is a simple unit that could easily handle this, or you could go to the more complex PIC / Arduino / Raspberry Pi etc
Ie most of these controllers only require a pin to select direction, and a port that can output the required stepping rate, and you can make it track. If you want to get fancier, like knowing where you are, it gets a bit more complex :-)
Andrew

GC - South Aus
03-10-2015, 04:08 PM
Matt

In relation to Mac what version have you got?

A lot of them can be dual boot MAC and Windows OS.

I currently run both OS's on my 20" IMac which I think is 2.4Ghz Duo Core (older model). Generally if its an intel processor it works as a native PC! You choose what OS you want when loading the Mac (turning it on).

I guess I should point out that the only difference between this method and VMWare is that you can only run OS at a time. So if you want to switch to Mac or Vice Versa, you have to shutdown, restart and choose the other OS on boot up. But VMWare usually runs slower than a PC and can be a headache at time compared to a native PC operation of the same OS!

It is quite easy to do and instructions can be found online. There are plenty of instructional videos on YouTube too.
Regards

Gav

MattT
12-10-2015, 08:06 AM
I have had a week of reading and youtubing on stepper motors and drivers :confuse3:

I did say earlier I didn't want to spend a lot of cash on this but have decidecd to go with this system.

http://www.awrtech.co.uk/system5.htm

Does everything I want it to do and costs 195 UK pounds inc post. Given the exchange rate that is a bit more than I would have liked...could say that about lots of things...but at least it will work :D

One of these days when I have the head space I will learn about electronics.

Now it's back to the 2" pillow block build :thumbsup:

Thanks for the help along the way

:thanx:

Matt