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Future proofing a DIY dolly for open moco
http://forum.timescapes.org/phpBB3/viewtopic.php?f=37&t=2339
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Author:  Joachim Buambeki [ Thu May 13, 2010 9:36 am ]
Post subject:  Future proofing a DIY dolly for open moco

Hi,

sorry if this question is redundant, but I haven't found anything about my question.
I know it is a dolly question, but I figured that it would fit in here better than in the dolly forum.

Is there anything I should consider when building a DIY dolly in terms of being compatible with open moco?

If yes, please make it simple, since I am a bit technically challenged. :?

Regards
David

Author:  milapse [ Thu May 13, 2010 9:59 am ]
Post subject:  Re: Future proofing a DIY dolly for open moco

Just about 'any' stepper or DC motor could interface with omoco.

Kinda groovy eh! :lol:

Author:  shutterdrone-old1 [ Thu May 13, 2010 10:34 am ]
Post subject:  Re: Future proofing a DIY dolly for open moco

As milapse said, as long as you have _any_ sort of DC motor or stepper, it can be adapted to openmoco - even if you use an incompatible driver today, new, better replacements will be cheap.

For example, you can buy a fairly boring driver in a box for $100 from servocity, or you can get this for $50 which blows it away in every regard, you just have to add a couple of wires to complete it: http://www.pololu.com/catalog/product/1392

Building your system around components like this not only saves you money, it gives you ultimate freedom for future possibilities. In this case, this motor driver lets you control it from a computer, an RC ESC, a simple potentiometer, a serial interface from things like openmoco, or a pwm interface like openmoco. =) If you decide later you want ultimate accuracy, it lets you add and fine-tune a feedback mechanism.

My suggestion is - focus on components which provide options for how you interact with them. If you have any questions about the right motors, the right drivers for your motors, etc. I'd love to give you some info which would make it easier to find what you're looking for.


!c

Author:  Joachim Buambeki [ Thu May 13, 2010 3:08 pm ]
Post subject:  Re: Future proofing a DIY dolly for open moco

Thanks for both your replies.
shutterdrone wrote:
If you have any questions about the right motors, the right drivers for your motors, etc. I'd love to give you some info which would make it easier to find what you're looking for.
You can bet that I will come back to your generous offer, thank you!

Initially I wanted to go with aluminum truss (I work in a theatre and know that they are easy to handle and solid), but the it seems to me that a monorail is to be preferred, is that right? I am a bit worried about the seams of a truss (I have not found truss without any beads from the welding on the seam yet). I need to have the ability to disassemble into pieces between 4 to 6 feet for portability.

Also I wanted to drive the dolly using a belt, because I thought that it would be more sturdy, but here I read, that it is not recommended to use a belt.
milapse wrote:
I did come up with a design that was 'antz approved' . Basically (as I understand it) belts are no no... and you don't want to have long cabling.
Is a cable able to lift a light dolly in a vertical setup? Also I am worried that the cable and the driving wheel become slippery when it gets wet (slight rain)

Regards
David

PS: After my additional questions I think this belongs for sure in the dolly section rather than in the openmoco one, perhaps one the mods could move it.

Author:  milapse [ Thu May 13, 2010 3:21 pm ]
Post subject:  Re: Future proofing a DIY dolly for open moco

Joachim Buambeki wrote:
Also I wanted to drive the dolly using a belt, because I thought that it would be more sturdy, but here I read, that it is not recommended to use a belt.


You know that Antz is in Antarctica and Murray is doing a project on a northern ice sheet right? :-) That's why I was referring to belts being bad... for INSANELY cold environments.

Author:  matt b [ Thu May 13, 2010 4:53 pm ]
Post subject:  Re: Future proofing a DIY dolly for open moco

If you are using timing belts and planning to shoot with different track lengths you can make up correct length belts to suit each set up.

Or you can purchase an extremely long length and make up a special clamp that secures the belt in place but allows the excess length to pass through and to be safely coiled up out of the way.

I have an 18m heavy duty kevlar type belt from an old moco rig but I hardly use the entire length - but it's complete just in case a director wants a long track!

For longer runs we used to swap the belt pulley over to a sprocket engaging motor bike chain and shoot with that.

Author:  seant [ Thu Oct 28, 2010 10:50 pm ]
Post subject:  Re: Future proofing a DIY dolly for open moco

Hey Everyone, I just wanted to ask about the motor controller "shutterdrone" posted a link to.

http://www.pololu.com/catalog/product/1392

I noticed that the motor controller only allowed for control over one motor, i am really interested in building a rig that would control three (pan, tilt and dolly) is there a controller you could point me towards or a different thread that touches on that subject.

Thanks.

Author:  doubledark [ Thu Apr 21, 2011 3:47 pm ]
Post subject:  Re: Future proofing a DIY dolly for open moco

I'm also looking to do what the previous poster wants; any one able to shed some light on where to look ?

thanks

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