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brownrb
2015-02-13
2019-11-29
  • brownrb

    brownrb - 2015-02-13

    A place to share pictures of your successful builds

     
  • brownrb

    brownrb - 2015-02-20

    Wow Jim that looks really cool! Congratulations. The power on/off is a great idea, I wish I had of thought of it sooner. My PSU 12VDC 29A when powered off keeps power for 5-10s then drops. So my focuser has a bot of a fit powering down, I have taken to just pulling the DC plug to turn it off. I think I'll fit that switch.
    Neat looking belt drive, looks like a NEMA17 motor. Are you using the L293D shield or the DRV8825 driver?

     
  • Jim Stefancic

    Jim Stefancic - 2015-02-27

    Thanks, Robert. The stepper is a bipolar NEMA17 and the driver board is a DRV8825. I never was able to set the current correctly on it, so I am getting some "hysteresis": move 1000 steps one way-move 1000steps back and the endpoint is different. It could be that my focuser is slipping, but it won't matter a lot since the movements will be small around a manually set focus starting point.

     
  • brownrb

    brownrb - 2015-02-27

    Understand well about setting the pot on the DRV8825 board - fiddly and delicate, minute turns result in huge changes. Took me quite a while to get it right, I started with full steps and told the focuser to go, turned the pot till it was only just stepping (a fraction past the point where it sorts wants to move but doesnt). Then switched to half steps and repeated the process, a very small amount more, then to 1/4 steps till it sounded smooth. At that point it seemed fine, mind you I did this like a dozen times without using a multimeter to measure the current as I just couldnt seem to get it right by measuring the current,
    Cheers

     
  • brownrb

    brownrb - 2015-02-27

    With my NEMA17PG5, I can go in and out around 6000 steps multiple times and it always seems to land in the same place. This is using the L293D Sheild and a UNO.

    With my NEMA17PG27, with a Nano and DRV8825, I can go 34747 steps in and out multiple times and it is still very close if not in the same spot. I remember adjusting the trimpot (with a plastic screwdriver) using 1/4 microsteps watching and listening to the motor (no load connected) till it appeared not to be missing any beats/steps and running smooth. Very very fine adjustments starting from trying to not turning, to trying to turn but jittering, to turning and missing a beat/step to just right.

    I have noticed that with coil power ON (which I must have because its a heavy imaging train) the stepper does not even get warm after 20-30m. The steppers I recommended draw like 300mA when set right, so that is 12*.3 or 3.6 WATTS, so these will run real cold. If you use a different stepper the amount of heat will depend upon whatever current limit the pot is set to.

     
  • Milen Velinov

    Milen Velinov - 2015-03-14

    Hello Robert, here some pic of my build. Still awaiting the case from China so the controller is accommodated in a case from micrometer and the display is dangling. I did not try the reset circuit but will do next week. I'm very pleased with it and admire guys like you and Tom Carpenter(I'm using my build of his astroeq). At the moment I'm using the focuser with APT 2.81 and it works miracles! Autofocusing tool works very well. Only thing that is missing from the functionality of the high end commercial focusers is the automatic temperature compensation - which doesn't bother me as APT notifies me about the temp changes to make adjustment - brilliant! About the Linux support - the indi moonlite driver connects to the focuser, reads the current position, temperature and max steps but does not have option to turn the motor power on and supports only full and half step mode.
    It does not respond to the buttons in and out. I've tested it on linux mint 17 and ubuntu 14.04. For such a nice developed focuser would be nice to have indi driver wouldn't it? I will chat with the boys at indilib as they are willing to integrate as much hardware as possible. I'm not a programer as I left the trade 20years ago but I can help as a tester :).

     
  • Milen Velinov

    Milen Velinov - 2015-03-14

    And here is the source for indilib

     
  • brownrb

    brownrb - 2015-03-15

    Hi Milen
    "but does not have option to turn the motor power on and supports only full and half step mode"
    yes, that is correct as there are no moonlite commands for this. So that's not available in moonlite (ie moonlite does not support coil power off and only supports full and half stepping),

    If you are getting as far as connecting and having values displayed then no need for reset circuitry, that is not going to help.

    I have the moonlite files from the Indi site and was reviewing them yesterday. It does has a debug feature which would be very useful to have a look at any debug file. On the quick read of the code I cant really see any issue, though the debug file would help a lot.

    I will have a closer look at the GP/SN/FQ type commands in the INDI driver. It all sounds rather strange as it works without issue with the windows based moonlite drivers so I suspect there is something a little different about the INDI driver that I mightve missed.

    The temp comp is out of the question as a DIY solution as each users implementation will differ. As I understand it it has something to do with the thermal characteristics of the focuser - as theirs is enclosed and made by them then they know this. I was not able to find much related to this on the Net.

    Cheers and thanks for the photos, most appreciated
    Robert

     
  • brownrb

    brownrb - 2015-03-15

    Ok, had another look and I think I might know what it is.
    I need to know what version of the Arduino code you are running.
    I can make the required minor code changes and send you a version to test.
    Please use my email address that is listed in the pdf file, it will be quicker.
    Cheers
    Robert

     
  • brownrb

    brownrb - 2015-03-15

    "I will chat with the boys at indilib as they are willing to integrate as much hardware as possible. "

    Note: If they are interested to do an INDI focuser driver it would be best to use the newer v200 protocol support, this way it would have all the other advantages as well. Am happy to provide details and support where I can could not actively test as I dont run Linux. The v200 protocol doc is not posted here yet, but its final and all the code has been migrated in the yet to be released versions.

     
  • bj jones

    bj jones - 2016-01-19

    My build
    getting close to testing

     
  • brownrb

    brownrb - 2016-01-20

    Wow that looks impressive!

     
  • bj jones

    bj jones - 2016-01-20

    My PCB, i made following your readme file. this is my first PCB ever!

     
    • brownrb

      brownrb - 2016-01-23

      Hi BJ
      Just one other thing.I did not have any tinit liquid to finish the board, so I used the wifes clear nail polish to cover the finished pcb copper tracks once it was tested ok and before final mounting inside the case. . This prevents the copper tracks from oziding and causing problems later on.

      Cheers
      Robert

       
  • brownrb

    brownrb - 2016-01-20

    I must say that is one fine pcb for the first effort, you mustve been really really pleased. Ive made quite a few and still remember that poor excuse of a PCB I made first, using photo resist and all the whiz bang stff. Yours really shows what can be done with a few simple tools. Thats quality work, fantastic.

     
  • bj jones

    bj jones - 2016-02-01

    Heres is how i mounted it to my 8" Newt. I need to find a better belt and a larger pulley on the Stepper. i found a free 1" pulley, but would like to find a 1.5" to match the knob on the focuser. for a 1:1

     
  • brownrb

    brownrb - 2016-02-01

    or an alternative source

    https://sdp-si.com/eStore/Catalog

     
  • Martin Broger

    Martin Broger - 2016-02-02

    Here is my "monster" ;) It was my third attempt to build the focuser... I call him Mark 3 ;)

    Finally everything works fine. At some point I've decided to put the LCD in some extra case connected via straight through RS232 cable. Also the push buttons are external via RS232 cable. I only had to mount an RS232 jack for the pushbuttons somewhere in the main case. Will do this later...

    Pic 1-6 shows the empty case mounted on the motor bracket -> The orange thing ;) It is 3D printed and "developed" by le me. It's far away from perfect but it works very well.

    On pic 7+8 you can see that the two LED's are on a seperate board for easy soldering. Also the 10A10 Diode has found it's place.

    Pic 9-11 shows the external LCD and Handbox with the pushbuttons and everything put together. Have to find a nice place for the LCD on the tube also.

    Cheers
    Martin

     
  • brownrb

    brownrb - 2016-02-03

    Martin, one fine build, wish I had a 3D printer but alas most the spare cash goes into buying parts to try differernt ideas, sensors, buttons, lcd's etc. What I really like is how each user oversomes the challenges of mounting the focuser and the use of belts, extensions etc. You have been very inventive indeed! Congratulations Martin, a jobe very well done indeed! And many thanks for the photos, it really is great to see them!

    Cheers
    Robert

     
  • bj jones

    bj jones - 2016-02-03

    Martin thats a Nice Unit, Glad to see you got the LCD going.
    Great job !

     
  • Martin Broger

    Martin Broger - 2016-02-03

    Thank you very much indeed guys! Rob had "pushed the right buttons" on my LCD to make it work.

    I did not own a 3D printer. I have used an online service. The parts itself are drawn in Sketchup Make and then converted to a 3D printer friendly file. Together with the brackets for the focuser I have also made the brackets for the motors for my EQ5 mount. Five pieces in total were 90 Euros + 15 bucks for shipping. Because of the high shipping cost I've decided to order all the parts together. Motor brackets are Mark2 ;) All in all not cheap but worth the fun. Especially this 3D printing stuff is the greatest invention since the invention of fire ;)

    Probably not helpfull for the guys outside Europe but here is the link to the 3D printing service. Shipping to the rest of World is 20 Euros. http://www.fabberhouse.de/default.aspx

    Cheers
    Martin

     

    Last edit: Martin Broger 2016-02-03
  • Jeremy Bolesky

    Jeremy Bolesky - 2019-11-29

    The focuser is working great, and I can control it from CloudMakers AstroDSLR using a Mac. I haven't had good seeing conditions yet to use AstroDSLR for full autofocus, but I'm confident the focuser will be able to handle it.

    I learned a lot with this build!

    While I was getting parts, I came across a project with voice feedback, and decided that would be a nice feature to replace the buzzer. Then I decided I wanted to do a little more with the voice, so I added a switch with a button that plays snarky Star Trek quotes.

    I decided to put the control board in the box with the motor-I needed room for a speaker anyway. I also replaced the db9 and USB connections with aircraft connectors because I hate cutting odd shaped holes in project boxes. One of the things I learned was how to use laser printer compatible water-slide decals to make nice project box graphics. I'm pretty happy with the results.

    I designed the rings and mount for the motor, modeled them in Fusion360, and had them 3-D printed. The mount turned out much better than I expected on the first try, but it's not something I would want to attach in the dark.

    In spite of the instructions saying to buy pre-made jst connectors, I tried to crimp my own. Big mistake. I had no idea they were so difficult-making them is like reconnecting amputated butterfly wings with a staple gun. I started with solid wire, which kept breaking at the connectors. I remade them with stranded wire, and they were still a little flaky. I ended up buying pre-made jst pigtails. Unless you've made a lot of jst connectors in the past, save yourself a lot of frustration and buy them.

     

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