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Electronics => Electronics => Topic started by: videorov on April 23, 2008, 06:57:14 PM

Title: Which is smoother for panning a camera stepper motor or servo and
Post by: videorov on April 23, 2008, 06:57:14 PM
Which is easier to control over a 100ft cable that will go to the camera in a waterproof housing.
Trying to figure out which way to go. I want to pan up to 360 degrees  manual mode and would like to have a auto pan mode too. Then I could let it sit and pan back a forth.
Is a servo easy to program to such a thing. I know steppers can looks like, but are they smooth.
Servos should be smooth for panning I would guess.
It all has to work over a 100ft cable in the waterproof housing.
What do I need to do to get this built. Any software out there for making my own
squences for panning.
Power source is 12volts on the boat.
Want to make a paning camera turn up to 360 degrees.  I want to control from a control panel
buttons etc, not just a computer. If a computer could also hook to it that would be a plus.

Title: Re: Which is smoother for panning a camera stepper motor or servo and
Post by: cooldog on April 23, 2008, 07:15:17 PM
I'd say steppers i think the pulse for the servos world deteriorate over that far of wire
Title: Re: Which is smoother for panning a camera stepper motor or servo and
Post by: JesseWelling on April 23, 2008, 07:52:11 PM
My first question is: what kind of camera? How is the video signal getting back to you?
Title: Re: Which is smoother for panning a camera stepper motor or servo and
Post by: izua on April 24, 2008, 01:10:55 PM
steppers do steps, so there will be some ringing before the position stabilises. they can do many turns. you can smooth out the steps using microstep, but it's a real pain if you don't have adequate drivers
hobby servos don't do steps and they move smoothly (if commanded right), but also they can't turn 360.
Title: Re: Which is smoother for panning a camera stepper motor or servo and
Post by: pomprocker on April 24, 2008, 01:15:43 PM
steppers do steps, so there will be some ringing before the position stabilises. they can do many turns. you can smooth out the steps using microstep, but it's a real pain if you don't have adequate drivers
hobby servos don't do steps and they move smoothly (if commanded right), but also they can't turn 360.


how about mount one 180deg servo on top of the other, and one can turn the first 180deg and then engage the second one to rotate the other 180deg for a full 360 in one direction. and it would also work going the other way.
Title: Re: Which is smoother for panning a camera stepper motor or servo and
Post by: airman00 on April 24, 2008, 02:48:59 PM
or how about put a gear on the servo and then mesh a larger gear with two times more teeth  to each other . This will make it turn 360

looks something like this
(http://www.servocity.com/assets/images/SPG755_Small.jpg)
Title: Re: Which is smoother for panning a camera stepper motor or servo and
Post by: videorov on April 25, 2008, 06:58:30 PM
Yes airman00 that looks like turning a larger gear would work.
JesseWelling the camera is just a color video board camera 380 line res 3.6mm small camera.
The video is coming back to me over copper wire for video.
Yes cooldog I was wondering if the servo pulse might get weak at 100ft on the wire. I wonder
if there is a way to keep the pulse strong over the 100ft cable.
Im not using a reciever to talk to the servos in this application. Im direct contol.


Im looking to pan a camera for my underwater camera thats in a waterproof housing. I would like to pan
up to 180 on the right of center and then rotate 180 to the left of center. That way I will have about 360
total. Is there a way I can do this?
Im not using a reciever to talk to the sevos since its down in the water on a wire cable.
Ive read where there are emulators I can use to talk to the servos over a hard wire.
I see where servo city have servo recorder that can control a servo direct too.
It doesn't seem that hard to come up with something that would work. I would have to
have some kind of a voltage regulator over the 100ft wire. Some say I might have some servo chatter
on a wire that long but were not sure.
Im wanting to just pan right now and maybe tilt later. I see where servo city have software where you
can program servos to do diffrent things. I would like to have the camera have a auto pan mode too and
I guess I could do that with that software with digital servos.
Im trying to find out what I can do with these sevors and what I can't.
Ive also considered a stepper motor to pan the camera, but I thought the servo might do a smoother
pan.
Just a project Im learning with.

Thanks for all the replys guys. Im trying to figure out what I need to buy to do what I want to do.
Looks like there are alot of things to program the servos is I can keep the pulse strong over the long
wire run. Airman00 has a good idea using the larger gear idea to get a 360 pan. I don't need a full 360
but close. The camera has 3.7mm lens at 92 degrees view its farly wide.

Im also looking at a clear dome to mount it in or maybe a round tube of acrylic if its not to sharp of
a bend, that might distort the image. I see on ROV's they have a dome on the front and the camera
seems to see through it ok.

Has anyone captured video though diffrent types of domes tubes canopys etc and found one to be better
no distortion?


Thanks for all the replys and help guys.