Arduino Ascom focuser Mark2

[D4N]

Just finished making one of these for my scope, so far very impressed with it

/Dan

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[tekkydave]

Just finished making one of these for my scope, so far very impressed with it

/Dan

Sent from my iPad using Tapatalk

Hi Dan,

Glad you like it.

[Peakedge]

Have now completed my focuser now and installed. Thanks very much, tekkydave.

I have no problem using the focuser manually in APT and am delighted but am struggling setting it up for autofocus.

Has anyone managed this and got any advice?

David

[calli]

Hi,

I am on my way to build another incarnation of that nice project. CAD is quite ready and I also printed the first parts. I printed the mount and the motor plate seperately and fixed it with bolts and nuts. So I can better "iterate" over versions to recover my bad design skills :-) And i don't need any support structure printed.

I am also trying to make a simple Android APP to control the focusser via Bluetooth. I used so far AppInventor 2 for it but it can be a beast doing more complex things with it. So far I can control it but the feedback ist not very good, because I did not found a good method to sync button pressing and the arduino sketch (original AAFM2). I seems to me that we could need some syncronous commands also in the Sketch, so that a MOve command will not immedeately return an OK but only when it actually reaches the desired position. I tried something with H# command but so far not with good results. Also the decelleration close to reach the end position is not a feature I like for the "Handcontrol".

I could easily modify the sketch but of course I want to keep it compatible and have the possibility to use ASCOM or manual control by a android device.

At the time I am waiting for the belt. I used a T5 belt becaus thats what I can print more easy.

BTW: I tried to get the motor running with AStepper and Stepper libs but failed (normally I use poluluo drivers and NEMA motors). What is the secret of this thingy? With the AAFM2 sketch it runs smooth....

Cheers,

Carsten

 

PS: I am sure I forgott something, so be prepared for more postings as I cant edit so far. Seems I can now!

Edited January 24, 2016 by calli
Because I can! ;-)

[tekkydave]

Hi calli,

That's all looking great to me. I originally had the move (Tnnnn) command waiting for the focuser to get to the position before returning to the calling program. The problem is it blocks the driver from any other comms with the nano. I suppose for short moves it doesn't matter but I decided to just send target positions and let the nano do the work asynchronously. I like your motor mount - it might be worth uploading it to Thingiverse as I'm sure others would find it useful. I have yet to design & print a bracket/mount I am happy with. Also, don't worry about being compatible with any of my code. I did the project as an experiment in Arduino and Ascom programming to get to know the environments so please feel free to borrow or steal any parts of it you find useful. If you think it's useful to others put it up on Sourceforge as a project. I have had mine downloaded by people all over the world, not just SGLers.

[calli]

Hi Dave,

any chance you can include the sync move command again? As addition, so the ASCOM can use the asynchronous ones and for controlling "by hand" we have the sync command. The reason why I dont want to make my own sketch is that of course I want to use the upstream version and not have to change or backport when I want to use either handcontrol or ASCOM. I can try to put it in and send you a patch of course.

Maybe we can discuss this more. I think a synchronous version of T which only sends a OK when the position is actually reached would be also sufficient. And I have to experiment more with the H# command maybe this can solve my problems also.

 

I will upload the CADs to thingyverse of course.

 

Carsten

[calli]

I think I can use H# and M# for getting the effect. Now I have to get that into the Android app...

 

Carsten

[tekkydave]

Could your app set a target using the T# command then call M# in a loop until it responds M0 indicating it has reached target position. Or even call P# to check the current position until it matches the target. This would avoid breaking the way the existing driver & sketch work. The Ascom drivers are designed to be async. I don't have a a version that uses async it was just a method I used when I started the project which was discarded.

[calli]

Yep. Thats the plan.

 

Carsten

[calli]

Ok, got it!

Here is the APK and the MIT App Inventor 2 Sources. The App Inventor is a graphical online/cloud APP maker. You programm with logic bricks. Easy but can get messy for more complicated things...

Click on "Connect" to connect via Bluetooth. I used one of theese cheap Bluetooth modules for Arduino. Be sure to match the serial speed for the Ardunio AAF Sketch and the BT module. This way you can control the AAF fine and coarse. The Send button and the logging is only for debugging.

Now I have to get that into my DEW Heater Box and combine it with the heater control...

Best,
Carsten

Edited January 25, 2016 by calli

[calli]

Getting a bit crowded in my box... I managed to combine my Dew-Heater sketch and the AAF sketch and control it by my mobile phone.

I added a connector to the fousser and a bluetooth module. Now with the mobile phone as control box I wanted the absolute temperature back... I guess I will change that. Of course then the AAF can also use that temperature.

Because I am waiting for the belt, I searched my RC-Heli stuff and found a T5 belt from my (sold ong times ago) methanol engine 50er TRex. I did cut it (overlaping) and glued it with CA. I did not expect much but after pressing the connection I cant ripp it by hand...

Carsten

[calli]

Ha,

just tried it "for real" (but at daylight). SOOOOO great! Only a minimal vibration from my glued belt and my printed pinions, but still much better than shaky-hands-carsten-try-to-hold-breathe-focussing.

Now design and print a housing for the motor driver and solder some cables.

Carsten

PS: For the temperature compensation of focus.... How is this calibrated? And which software is doing it?

[tekkydave]

The temperature compensation is normally done by the client application so you will need to find an algorithm and build it into your app.

[calli]

Yea, sorry for beeing unclear here. WHICH client app? Are there free ones?

 

Carsten

[KRYPTON]

Has anyone built a Focuser that can be controlled by an Arduino micro-controller using  infrared remote control? I am in the process of building one but have little experience with coding. If someone has made one I would be grateful for a look at you code/sketch. Many thanks

Ken

[Mav359]

Hi Guys

Sorry but i am being extremely lazy, i tried reading through the post and went a little brain dead so i'm just gonna ask the question....

I have had my focusers for my C9.25 & Mak127 for a couple of years now based on the original SGL Yahoo group and they have worked brilliantly, took a while to get a system working, i have to plug in the USB first wait a moment for the Aurdino to boot then plug in the easy stepper board. They work great, little dated with a bigger stepper motor and the easy stepper board but all good.

The software i'm using though is the original SGL Yahoo group software which whilst it works is a ok at best, so where are you guys at on a software front and will my easy stepper board work with anything thats has been developed from here?

[calli]

4 hours ago, KRYPTON said:

Has anyone built a Focuser that can be controlled by an Arduino micro-controller using  infrared remote control? I am in the process of building one but have little experience with coding. If someone has made one I would be grateful for a look at you code/sketch. Many thanks

Ken

I was actually considering this. I have a neat little IR from a old Sony cam. There are many projects and libraries for IR . however i then decided to go for Bluetooth because that opens control from PC and mobile or tablet and at least my mobile is always in site. The focusser sketch (maybe  use the Mark 1) is easy to understand and expand . just ask here if you need help.

 

Carsten

 

Carsten

[KRYPTON]

Thank you  Carsten for your advice on a Bluetooth version. I have looked at the schematic and the input to the system seems to be a temperature sensor. What would this be replaced with for a Bluetooth version?

 

Ken

[calli]

No you just don't use the USBtoSerial connection but connect the TXD/RXD Pins crossed(!) and VCC and GND to the Bluetooth module (usually they came preconfigured at 9600baud 8N1 check this!). On Arduino Pro or such without a proper USB connector this shares pins with the Sketch upload, so you have to disconnect the Bluetooth Module for Sketch updates. All other connections stay the same. An Arduino has plenty ports to use ;-)

Have a look at my image above. The BT module is bottom left, 4 wires red VCC, black GND, the others TXT/RXD.

As soon as the physical connection is there and the config BOTH in sketch and on the BT module is corect you should be able to connect. However... On my Win8.1 PC it was a pita to get the BT working. These options are all scattered around. But now it works (after some 20 Minutes, the Android was like 10 seconds...)

Carsten

[tekkydave]

17 hours ago, Mav359 said:

Hi Guys

Sorry but i am being extremely lazy, i tried reading through the post and went a little brain dead so i'm just gonna ask the question....

I have had my focusers for my C9.25 & Mak127 for a couple of years now based on the original SGL Yahoo group and they have worked brilliantly, took a while to get a system working, i have to plug in the USB first wait a moment for the Aurdino to boot then plug in the easy stepper board. They work great, little dated with a bigger stepper motor and the easy stepper board but all good.

The software i'm using though is the original SGL Yahoo group software which whilst it works is a ok at best, so where are you guys at on a software front and will my easy stepper board work with anything thats has been developed from here?

I think a couple of others have asked the same question before. I don't know if anyone succeeded but a search of the topic may find an answer. I think the easystepper uses step/direction pins rather than driving the coils individually. It should be possible using my sketch if you modify the clockwise() and anticlockwise() functions to pulse the correct pins on the nano. Maybe you could steal the relevant routines from the SGL sketch and substitute them for the clockwise() and anticlockwise() function calls.

[KRYPTON]

Thanks again  Carsten I have a BT module on order. Do you use a phone or laptop to communicate with your focusser and what software did you use to control it?

 

Ken

[calli]

1 hour ago, KRYPTON said:

Thanks again  Carsten I have a BT module on order. Do you use a phone or laptop to communicate with your focusser and what software did you use to control it?

On PC you could theoretically (I did not test it so far) use the ASCOM drivers from Dave.

On my mobile I wrote a APP which you can get here: https://dl.dropboxusercontent.com/u/4898693/FocusserAPP.7z

Its for my combined DEW Heater but I guess it will work for the original Sketch as well.

Carsten

[calli]

Hi folks,

I am a bit concerned about the motor and its bearings due to the pull of the belt. I am not sure if it is designed to take these lateral forces? What are your long time experiences?

Carsten

[calli]

Just to let you know that I also managed to install the ASCOM Platform and can now control the focusser via Bluetooth(!) from PC also! My additions to the sketch (for the dew heater) did not break something it seems :-)

I would like to have a generic command line in your FocusAAF.exe, that way I could also control my heater.

Great Stuff!
Carsten

[Mick J]

15 minutes ago, calli said:

Great Stuff!
Carsten

Great Stuff indeed Carsten,  just wish I understood half of it.