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Tiny servos for lens control

Discussion in 'Electronics' started by Jose Luis Ocejo, Oct 11, 2012.

  1. Josh Lambeth

    Josh Lambeth Well-Known Member

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    Thanks for that link...

    Ill start playing with this later today probably... Time to go build my copter again (just got back from Denver... where I now have 2 more bad motors. UGH!!!!!!!)

    Josh
     
  2. Andrew Goodwin

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    I've used the Xbee utility to 're-flash' some of our units. The key with that software is to do it several times. Just because it doesn't work the first time you try doesn't mean it won't work the second, or the 11th time you try.
     
  3. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Bad as "dead" or bad as in noisy? I'm just replacing some motors because I think they're causing vibration, so I'm just wondering what "bad" means. :)

    Andy.
     
  4. Jose Luis Ocejo

    Jose Luis Ocejo Active Member

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    All this is very cool but .......Any thoughts on the servo for the lens.......maybe.......
     
  5. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Oooops, JLO, sorry...the thread drifted. I think the closest we came was Katya's reply on page 1, message #8 when she referred us to Philip Bloom's web page. I think the short answer is, thus far, we don't know the answer to your question. Apologies!

    Andy.
     
  6. Jose Luis Ocejo

    Jose Luis Ocejo Active Member

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    Hi guys I had a reply from Arthur the owner of the picture with the servo on the len,s he is in the middle of some shoot in Brazil, any way he briefly mention what is involve to make this happen and there is some modifications to the inside of the servo he will post instructions as soon as he has a chance apparently several people have ask for this any way thats that on the other hand that possibility of communication with the Canon using the Xbee is pretty cool
     
  7. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Hi JLO:
    Were the modifications to the servo just to make it able to turn complete revolutions without a hard stop?

    Andy.
     
  8. Jose Luis Ocejo

    Jose Luis Ocejo Active Member

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    here is the reply I got:


    That servo I've used is a ALIGN DS410 Digital. I used that only because I had it around. The zoom system is still in beta, I've modified it a lot since that picture. The most important mod is that I had to modify the servo, had to remove the potentiometer and replace it with 2 resistors - just like the Cinestar Gimbal with the Radians or the Pan servo - and hd to install 2 microswitches between the servo PCB and the motor. This microswitches are used as a servo travel limit.

    Why I had to do that? The pot mod was because the servo didn't have enough travel to move the lens ring all the way, so I had to increase the travel or use a bigger gear. With a bigger gear I'll lost precision.... so... longer travel. But with the mod the servo didn't know when to stop moving, and during flight we already have a lot of things to think about, and to remember to stop the zoom command when it reaches the limit wasn't in my priority list. That's why I had to install the switches.

    As soon as I get back home, I'll prepare a quick assembly manual for the system. Many people are asking me about it.

    Cheers,
     
  9. Katya Nelhams-Wright

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    Hi JLO
    I already have a set of these for my Canon EF lenses but I was thinking that you would have to put a lot of pressure on the servo gear to make the connection with the half inch lens gear robust enough to drive the lens. Do you think it would be possible to get it snug enough to all work?
    Kat
     
  10. Jose Luis Ocejo

    Jose Luis Ocejo Active Member

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    Well once you pull on the zip tie gear hugs the lend pretty nice I don't see the gear slipping, or perhaps your question is the necessary presure that the servo need so the teeth on the gears don't jump, well it depends on the hardware u use to mount the servo on, also if the lens is cold it could be more stiff
     
  11. Katya Nelhams-Wright

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    Hi JLO.
    Yes I was wondering whether the necessary pressure could be put on the servo so the teeth don't jump. I have considered mounting the servo actually on the lens so that it was pushing against itself and then not particularly affected by the tilt of the lens. I guess it depends on how small the servo is. All food for thought but would love to rig something up soon if you figure something out:)
    Kat
     
  12. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Katya/JLO: Might you not be better off using a toothed drive belt? They don't need too much pressure to engage.

    Andy.
     
  13. Arthur Vieira

    Arthur Vieira Flight Squad

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    Wow, I was on a trip and missed this post. I'm still catching up.... Sorry for the absence.
    This weekend I'll draw some schematics of my Zoom control and the servo mod. I got all parts easily on the web.
    I'm using it for zoom only as my AV link doesn't have enough quality for focus adjustment and because in 99% of my flights I don't need to touch it.
    Some considerations.
    I used a gear/follow focus rig because a rubber wheel touching the lens or a belt system, in my opinion, would require a lot of pressure between the lens and the servo and this would :
    A: require a heavier/stronger setup.
    and or
    B: be able to move the servo or camera out of alignment during flight (Pressure + flight moves).

    I'll post the drawing here this weekend.
     
  14. robert Luxton

    robert Luxton New Member

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  15. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Rob:

    Firstly, if it's not too much trouble, would you be kind enough to change your user name to your real first name and last name, please? The reasons for this (and how to do do it) are explained here: http://forum.freeflysystems.com/index.php?threads/real-names.497/

    Secondy, that's a neat idea. The issue would be how to set up what is, in effect, a bidirectional USB connection between the controller on the ground and the camera in the air that is good enough that (a) the controller thinks it's talking to the camera and (b) the camera thinks it's being talked to via the controller.

    Something like this might work, but the range is only 30 feet.
    The problem is that if you search for:
    wireless usb
    you get a plethora of Wifi access devices that plug into a USB port.

    It think what you need is something perhaps called:
    cable-less usb
    Or some equivalent.

    Let us all know if you find something that has decent operational range.

    Andy.
     
  16. Cris Olariu

    Cris Olariu Member

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    I'm wondering if anyone fully figured out a solution for this. Looks like everyone abandoned the topic...
    In any case, I started looking at this product: http://jag35.com/weffv2.html
    I found out from some of the reviews that it has a range of 1000 ft operating on the 2.4GHz band.
    Any thoughts?
     
  17. Gary Haynes

    Gary Haynes Administrator
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  18. Tim Joy

    Tim Joy Active Member

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    Here's something I built. It was made for the GH2 and now doesn't fit the GH3... oopps.

    It works well. It's a 10-turn pot so it has a lot of travel and great resolution. I haven't used it in flight because the winter made the lens too sticky. I suppose it could be mounted elsewhere, in front underneath.

    Edit- to add, the whole assembly weighs about as much as a standard servo and the servo used is a hitec MG HS81

    I think it would be much better to build a long arm that comes off the lens for more leverage. This design puts a lot of pressure on the lens and mount unless the zoom is very smooth and friction free.
     

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  19. Josh Lambeth

    Josh Lambeth Well-Known Member

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    Which Pot is that? I was thinking about using one of the old ones from the CS Gimbal before Radians.

    Josh
     
  20. Zach Beggs

    Zach Beggs Member

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