IIDC Camera Control Library

I have a somewhat off-topic question. I'm working with mobile robots and
laptops, and would like to untether my cameras from the wall power. Does
anyone have suggestions about battery powering IIDC video cameras?

Thanks,
Jason

Hi,
I use a pcmcia card with 6pins connectors; the card have a 12V input to 
supply power to the camera , then I need a extra power supply for the 
laptop(the pcmciacard in fact) but not for the camera.

If you need to run the laptop from battery it might be possible to 
extract the 12v for the pcmcia card from the laptop too.



Jason Meltzer wrote:

>I have a somewhat off-topic question. I'm working with mobile robots and
>laptops, and would like to untether my cameras from the wall power. Does
>anyone have suggestions about battery powering IIDC video cameras?
>
>Thanks,
>Jason
>
>
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Reply to the mail from Jason Meltzer (jasonm1@...):

> I have a somewhat off-topic question. I'm working with mobile robots and
> laptops, and would like to untether my cameras from the wall power. Does
> anyone have suggestions about battery powering IIDC video cameras?

I use an Apple iBook running Linux just for this reason: It provides power on the firewire bus while running on battery. 

Beside that it should also be possible to carefully remove the shielding from a 6 pin cable, connect the power cords to a battery and carefully rere-shield the data cables.

 -Arne

Hello!

Arne Caspari sagte:
> Reply to the mail from Jason Meltzer (jasonm1@...):
>
>> I have a somewhat off-topic question. I'm working with mobile robots
and
>> laptops, and would like to untether my cameras from the wall power.
Does
>> anyone have suggestions about battery powering IIDC video cameras?
> Beside that it should also be possible to carefully remove the shielding
from a 6 pin cable, connect the power cords to a battery and carefully
rere-shield the data cables.

You could use a small firewire-hub, too. Almost every hub has a additional
 power-in for supplying the connected firewire-devices. It should be easy
to find out the correct voltage and use a Battery for powering the hub.

Cheers,

Markus

The battery approach definitely works; I've done it.  A nice approach
might be to build a little circuit board with a firewire jack and a 9V
battery connector or two (a device can supply up to 30V) wired up to the
right pins.  If you wanted to get fancy, you could add a diode to keep
your battery from blowing up if there's already, say, 12V on the bus.=20
With something like this, you could just daisy-chain it onto any bus that
needed power.

-A.J.
aja@...


Arne Caspari said:
> Reply to the mail from Jason Meltzer (jasonm1@...):
>
>> I have a somewhat off-topic question. I'm working with mobile robots a=
nd
>> laptops, and would like to untether my cameras from the wall power. Do=
es
>> anyone have suggestions about battery powering IIDC video cameras?
>
> I use an Apple iBook running Linux just for this reason: It provides po=
wer
> on the firewire bus while running on battery.
>
> Beside that it should also be possible to carefully remove the shieldin=
g
> from a 6 pin cable, connect the power cords to a battery and carefully
> rere-shield the data cables.
>
>  -Arne
>
>
>
> -------------------------------------------------------
> This SF.Net email is sponsored by BEA Weblogic Workshop
> FREE Java Enterprise J2EE developer tools!
> Get your free copy of BEA WebLogic Workshop 8.1 today.
> http://ads.osdn.com/?ad_id=3D4721&alloc_id=3D10040&op=3Dclick
> _______________________________________________
> Mailing list for libdc1394-devel
> libdc1394-devel@...
> https://lists.sourceforge.net/lists/listinfo/libdc1394-devel
>

On Tue, 20 Jul 2004, Arne Caspari wrote:

> Beside that it should also be possible to carefully remove the shielding
> from a 6 pin cable, connect the power cords to a battery and carefully
> rere-shield the data cables.

Why go to that effort when you can simply insert a powered hub in the 
line?

Firewire cable is double shielded, with the outer shield connected at one 
end and the inner shield at the other. I've found that if you short the 
two, you get really bad results. 

As for battery versus wall: the cameras don't care if the power comes from 
a battery or the wall. Just put 12 volts into the hub and problem solved.

Reply to the mail from John Stanley (stanley@...):

> 
> On Tue, 20 Jul 2004, Arne Caspari wrote:
> 
> > Beside that it should also be possible to carefully remove the shielding
> > from a 6 pin cable, connect the power cords to a battery and carefully
> > rere-shield the data cables.
> 
> Why go to that effort when you can simply insert a powered hub in the 
> line?

This is simple: If I am on battery, it means that I am mobile. A hub means that you need to have two cables, batteries with a small cable of their own and the hub intself but if you simply build this little cable, you only need to carry the batteries and the one cable. 
Beside that the hub will take battery power by itself. 

 -Arne

On Wed, 21 Jul 2004, Arne Caspari wrote:

> > Why go to that effort when you can simply insert a powered hub in the 
> > line?
> 
> This is simple: If I am on battery, it means that I am mobile. A hub
> means that you need to have two cables, batteries with a small cable of
> their own and the hub intself but if you simply build this little cable,
> you only need to carry the batteries and the one cable.

And if that cable breaks, you cannot simply go to the local computer store 
and get a new one, you must build a new one. There is a great deal to be 
said for using COTS hardware.

The overhead is one cable and a hub. Same battery, you still need one 
cable to the camera anyway.

> Beside that the hub will take battery power by itself. 

A trivial amount of power compared to the camera and the computer.

On Mon, 2004-07-19 at 20:23, Simon wrote:
> Hi!
> 
> I an trying to use the libdc1394 in order to capture
> videos from two Sony Dfw-vl500 iee1394 digital cameras at
> 640x480, YUV422 and 30 fps.
> I have only one firewire host adaptor.
> 
> If i start two instances of coriander i can 
> view the two streams like this:
> cam1: 640x480 YUV422 30fps
> cam2: 640x480 YUV422 _15fps_
> 
> That works. However if i change the second camera
> to 30fps coriander locks up and both cameras 
> show 0fps.
> I have to kill coriander, disconnect & reconnect the cameras
> in order to access them again.
> 
> The same happens with my own C++ program using libdc1394
> and also if i use dc1394_multiview (in 640x480,yuv422,30fps mode) from
> the libdc1394 examples dir.
> 
> I am using libdc1394 0.9.3 (debian unstable).
> Kernel Version is 2.4.25.
> 
> Does anybody have an idea ?
> The Bandwith of the firewireport should be enough:
> 2 cams * 640*480 * 16 Bits/Pixel (YUV422) * 30 f/s / 2^20 = 281,25 MBit/s
> 
> Which is smaller than the 400 MBit/s of a firewireport.
> Or am i wrong ?
> 
> Has anyone managed to capture with 2 (or more) cameras @30fps in full res ??

I do that a lot and have no problems. One thing I did not try is to
launch 2 instances of coriander. Have you tried to run the example
programs in gdb?

Damien

-- 
  _    Damien Douxchamps
 ('-   PhD Student / Research Assistant
 //\   Image Processing Group, Communications Lab, UCL, Belgium
 V_/_  http://www.tele.ucl.ac.be/MEMBERS/Douxchamps_Damien_e.html

On Friday 23 July 2004 18:44, Damien Douxchamps wrote:
> > 2 cams * 640*480 * 16 Bits/Pixel (YUV422) * 30 f/s / 2^20 = 281,25 MBit/s
> > 
> > Which is smaller than the 400 MBit/s of a firewireport.
> > Or am i wrong ?
> > 
> > Has anyone managed to capture with 2 (or more) cameras @30fps in full res ??
> 
> I do that a lot and have no problems. One thing I did not try is to
> launch 2 instances of coriander. Have you tried to run the example
> programs in gdb?
I have only one firewire card installed, you too ?

Do you capture with _both_ cameras 
640*480 (YUV422)  at 30 fps ?

Arne wrote (not shure if he wrote to the list or only to me) that this should be impossible
because one videostream (640x480, yuv422, 30fps) eats
64% of the wirewire Bandwidth
(see http://www.1394imaging.com/resources/backgnd/1394/video_bandwidth/ )

If it is working for youcould you send me some more information about
which libdc version you are using ?
Thank you very much !

Simon