[Konvas] off-topic -- motorized heads

[Sean McVeigh]

Definitely a cool feature.  I thought about doing this, but I think  
due to my rather high gearing ratio, there will be no way to free-move  
the head by hand without somehow disengaging the motor.  Definitely  
something I'd like to see in the next (2-axis) iteration :)
As for storing the data, I can appreciate the usefulness of the laptop  
in that instance, but again, it's only a couple KB worth of data to  
store a move.  Easily accommodated in the flash of a small  
microcontroller (there are some pretty substantial low-cost, low-power  
system-on-a-chip type parts nowadays), or in an attached piece of  
compact-flash or similar couple-dollar part :)  And it'll run off a  
tiny battery for days :)  Heck, we're at the point where we can record  
hours worth of audio on a single tiny flash card.  Telemetry data is  
peanuts compared to that ;)

Speaking of CNC mill, that's my project for the spring!

Cheers,
Sean


On 11-Dec-08, at 9:25 PM, H. W. Stone wrote:

> The mechanicals were Off The Shelf geared units that were made for  
> CNC mills.
>
> The 'added feature' of the laptop is that you can "hand move" the  
> camera, recording it on the laptop, then having it reproduce it time  
> after time after time-- and save thousands of moves.
>
>
> -----Original Message-----
> From: Sean McVeigh <konvas at smallpony.ca>
> To: Konvas Discussion List <cinema at konvas.org>
> Sent: Thu, 11 Dec 2008 4:21 pm
> Subject: Re: [Konvas] off-topic -- motorized heads
>
> Thanks H.W. I'm more concerned with the mechanical resolution right  
> now, if you have any insight on that front.
> The controller has plenty of processing power, and I know he doesn't  
> want to lug a laptop around all the time, so I'm thinking something  
> on the order of 10 pre-programmed moves, plus a manual setting.  
> It'll have a tiny LCD and a keypad or dial or something similar for  
> manual setup. ie. set it to 5 degrees-per-minute speed and just let  
> it go. I should reiterate of course, that he's more interested in  
> very slow moves rather than snappy ones :) Like doing a panning  
> coastal sunset in timelapse, or similar.
>
> Cheers,
> Sean
>
> H. W. Stone wrote:
> > The people I have talked to recommend running it via a laptop--  
> not > directly. They also recommend MAC over PC, and that you use  
> Firewire > to connect it instead of USB2, but USB2 "will normally"  
> work fairly > well. That apparently keeps the problems to a minimum,  
> and allows you > to upgrade joysticks, controllers, and store moves  
> to use in different > locations weeks later, too.
> >
> >
> > -----Original Message-----
> > From: Sean McVeigh <konvas at smallpony.ca>
> > To: Konvas Discussion List <cinema at konvas.org>
> > Sent: Thu, 11 Dec 2008 2:49 pm
> > Subject: [Konvas] off-topic -- motorized heads
> >
> > I'm building a motorized pan head for a friend for xmas... was >  
> wondering if anyone has any experience with such equipment. I'm  
> using > a stepper motor coupled through a worm gear to drive the  
> plate... does > anyone see any problem with a 0.025 degree/step  
> (90as/step) final > resolution on the output plate? He mainly wants  
> to use it for very > slow pans and timelapse type work, so I think  
> it'll probably be fine.
> > I'm probably needlessly concerned, as I've maybe been paying too  
> much > attention to astrophotography-related websites while trying  
> to spec it > out, where the requirements are more like single-digit  
> arc-seconds per > step.
> >
> > Anyone want to recommend some features for such a head? Since it's  
> > going to have a microcontroller brain, I can probably do things  
> like > re-play moves for green-screen matching. Going to make it  
> programmable > off-line so that you could draw curves for it to  
> follow.. heck could > probably even take a dump from a tracker so  
> you could match-move new > shots for compositing.
> >
> > I guess next, he'll want a tilt head so he can stick the two  
> together > and plug a joystick into it :) oh.. there's another  
> feature!! DB-15 > connector :)
> >
> > Cheers,
> > Sean
> >
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