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Camera slider for medium/large camera

Discussion in 'Other Builds' started by PierreLenfestey, Jan 23, 2016.

  1. PierreLenfestey

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    Apologies if this has already been discussed - I haven't seen anything in the forum that's directly relevant to this, considering the size of the camera I'm using. I'm looking to build a motion control camera slider for a Sony PXW-FS7. I want to build just the one axis, but may add a pan and/or tilt axes later on. This probably means I'm looking at smoothly moving a weight of around 5-7kg very smoothly at speeds of approx. 10cm/sec. Ideally I'd be using quiet steppers in case I want to film with sound, but it's not a deal breaker.
    I'd also like to consider the possibility of using the slider in a vertical configuration, which means a vertical lift of around 5kg - although for this configuration I could probably strip the camera down to around 3kg.

    I've been looking at a 150cm, 20x80mm V-Slot rail with Nema17 and the extreme solid v wheels. The 80mm width is chosen for the stability I'd hope it'd provide for the camera platform.

    In terms of the configuration, I'm thinking of using a belt driven unit, with the V-Slot rail in a "landscape " orientation - 80mm side flat to the ground. Then I'd be using the belt (not sure if it should be 2 or 3mm) to wrap around the center of the V-Slot rail and attach to an 80mm gantry plate. The idea here would be to reduce any sideways stresses on starting the movement of the gantry.

    I'm also thinking of driving the Nema17 with a Big Easydriver controlled by Arduino and programming the unit to accelerate the gantry, rather than just straight up to speed.

    I'd love to hear if there is any experience in making such a thing, or if there's any advice on the construction and parts.
     
  2. Rick 2.0

    Rick 2.0 OpenBuilds Team
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    For something that substantial, I would probably go with a section of C-Beam (flat side up) and would also probably cut a 3/16" or 1/4" thick plate for a 6 wheel gantry. As for the vertical motion, using a counter weight over a pulley at the high end would be a good idea. The motor doesn't have to work so hard and you don't have to worry about the belt slipping and the system crashing.
     
    Mark Carew likes this.
  3. PierreLenfestey

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    Sweet! Thanks for that., I take it that the plate for the gantry is to stop it from deflecting under the weight of the camera?

    Love the site, by the way.
     
  4. Rick 2.0

    Rick 2.0 OpenBuilds Team
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    Yes, and when the plate flexes it loosens the grip of the wheels which can lead to a bit of play in the system.
     
  5. PierreLenfestey

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    Thanks, sage advice :)
     
  6. PierreLenfestey

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    So I'd like to place an order with Oozenest in the UK (to avoid excessive shipping charges) and so I need to make sure I'm getting the right stuff ordered.
    One thing I can't seem to get my head around is how the spacer plates work with the spacers. If I understand correctly, I'm going to need a pair of spacer blocks. On one side I have conventional spacers 6mm in depth which are 10mm wide, on the other side I have eccentric spacers which have a 7.14mm component which slots into the spacer block to allow for adjustment. Doesn't this mean that, even with tightening, the spacer block might allow the bolts holding the "fixed" wheels to deflect a little? or is it cool that there will be an M5 bolt going through a 10mm shaft until it reaches the 6mm spacer? Hope that makes sense.
     
  7. PierreLenfestey

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    And for that setup I'm guessing I have to use 40mm M5 low profile screws to attach plate, spacer blocks, spacers and wheels together.
     
  8. Rick 2.0

    Rick 2.0 OpenBuilds Team
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    You need to give us a much better idea of what you are building. I'm not sure why you are even needing the spacer blocks.
     
  9. PierreLenfestey

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    Thanks, Rick

    It's a belt-driven1500mm C-Beam kit to act as a Moco horizontal camera slider - one axis. I'm proposing to raise the mounting plate because I want the plate to be pulled from the center. The Nema17 looks like it can only be mounted in the center of the rail if it's attached vertically, in this orientation it seems as if the belt would have to be attached so that it stands above the C-Beam, not along the slots in the extrusion. With the belt circling the pulleys in this orientation, it looks as if the plate would have to be raised to accept the belt underneath the plate.
     
  10. Rick 2.0

    Rick 2.0 OpenBuilds Team
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    So basically something like this:

    [​IMG]

    What the drawing fails to show is the inset screws that hold the spacer blocks in place. They can be seen better here: (Same idea, different system. Note the screw heads just between the wheel screws.)

    [​IMG]

    For the short screws, 15mm ought do it. For the long screws, 3+12+6+11+4=36 so yes, 40mm will work.

    As far as the 5mm screw in the fixed side, no it really does not seem a good idea that it is wallowing around in a 7.14mm hole. Personally, if I was building this I would fill the holes in the riser block on the fixed side with J-B Weld and then drill them out at 5mm once the epoxy had set up using the smaller holes in the top plate as a guide.
     
  11. PierreLenfestey

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    You are wise and generous thank you very much for the advice :) and, yes, that top image is exactly what I was looking to do.
    The drilling idea is genius, ta.
     

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