19th April 2003, 14:28
I'm looking for a complete diagram to build my own motion control. Where could I find one to download or, maybe, buy one for a good price?
Another doubt that I have is about the software that would control the camera. Is there any software free for for this? In case not, what would be the better indicated and which is the price?
29th April 2003, 14:38
i'm sorry i did not see this post sooner or i would have replied.
i was a motion control cameraman for some years and might be able to shed some light on your situation.
while the underlying concept of motion control is very simple, the level of integration required for good film work is quite sophisticated and not to be ventured into lightly. one man, Bill Thomas of Kuper Controls has pretty much devoted his career to developing software just for this purpose.
if all you are looking for is a "diagram" then i'm afraid very few resources exist....all of the motion control systems out there are either custom built or of a proprietary nature (Mechanical Concepts, General Lift, Tiffen, Sorensen and Mark Roberts all have excellent and well engineered rigs). my best suggestion would be to figure out what you need moco for then try and design a simple rig to accomplish only the tasks you need (i.e. pan/tilt only or pan/track, etc).
you can find TONS (literally: TONS) of used moco gear on the secondary market: swap meets, manufacturing closeouts, ebay, etc.... this includes linear slides, bearings, rotators, motors, drivers and ballscrews. if you or somebody you know has a bit of mechanical prowess you can frankenstein these surplus/used parts into a very servicable motion control rig.
as for the software to control it there is really only one choice, the RTMC cards from Kuper Controls and the software that goes with it. they sell for a variety of prices depending on the number of axes you need. my guess is that Bill would probably sell an older RTMC card with 16 axes for around $1500 or less. it's been awhile since i bought mine so i'm not current with the prices (plus he's come out with a few updated products in recent years which might have driven down the price of older cards).
his software is the industry standard and contains all of the bells and whistles you need to correctly interface a film/video camera into a motion control system.
so, to recap here's the design/hardware/software "diagram"
the software runs on a PC.....the PC has a dedicated hardware card that generates a set of signals (step&direction) that tell motors when to move.....these signals go into what are called drivers (basically powersupplies for stepper motors), these drivers convert the digital signals into the correct power phase for steppers to operate.....the drivers send power to the stepper motors and the motors move in discreet increments.....the motors are hooked up to either linear (track, lift, boom) or rotary (pan, tilt, swing) actuators which move your motion control system around. the camera is a special case which is handled as a special rotary axis by the software to take into account shutter phase, framerate, etc.
if you'd like more info including contact info for the vendors i've listed feel free to contact me off-list.
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