Running CCD cameras from a PC PSU

[Maxxarcade]

I have a Linux based DVR setup which I am soon upgrading the cameras on. I just bought 4 Sharp 1/3" CCD cameras off ebay that require about 400ma each, at 12V DC.

I was hoping to simply run them from the DVR PC's PSU, which is a 300W Sparkle. My only concern is about noise coming from the PSU and affecting the picture. Can I just add another 2200uf or so low-esr cap in parallel with the 12V output, or will it cause problems with the PSU? I was just going to mount a barrier strip on the back of the PC for making a 12V bus for all the cameras, and just put the cap on that.

EDIT: Oops, wrong topic... Should have probably posted this on the power supply forum.

[gonzo0815]

Re: Running CCD cameras from a PC PSU

The problem is probably not the noise from the PSu, than probably the noise from the HDD`s and other 12v supplied HW.
I have done this with the 5v and the 12v rails of my older system, to power the speaker and my USB hub with that and eliminating those cheap & hot wallplugs and clear off the mess on the desk.

The USB hub does not have any problems with that, but my cheapo speakers get disturbed from the elektronic garbade produced by HDD`S adn GFX card.
So there was a permanent humm probably the dc HDD motor and some fans.
Additionally i could hear the mouse pointer moving and some other gfx related things there.
I tried to fixe this by adding some ultra low esr caps, a coil (first some small coils, then the biggest one i have had in the junk box) and a few small HF ceramic caps to form a pi filter.
But without succes.
The system was not affeckted from the capcitance, as long as you do not attache them, when the system is running (i think this is obviouse).
The other aspekt is, that you do not overdo it, as the ATX spec defines a max startup capacitive load.

From my point of view, i would say, the only way to clear off the noise & garbage from the line, would be a linear voltage regulator sutch as the 78xx or LM317 or the low drop alternatives.
A linear voltage regulator has very high noise rejecktion, if properly build.
As the 12v is already the lower limit for my speakers, i could not do that, whitout putting in a step up circuit first (wich was a littel to mutch effort, to eliminate one wallplug...)

Botom line: any digital device should work fine with the noise & garbage, but analaog circuits wich have some kind of amplifier in it are not easily decoupled.

[dood]

Re: Running CCD cameras from a PC PSU

We used to run all our cameras off of an old AT PSU, before we upgraded to a real power center. It drove the cameras fine, but that's all it was doing, it wasn't powering anything except the cameras. Perhaps this would be a better route to take. I'm sure you can dig up an old AT PSU somewhere

[kc8adu]

Re: Running CCD cameras from a PC PSU

it will work fine.
i added a small blaupunkt car stereo amp to a garage pc so a friend could play her mp3's with some real speakers attached.
had to put a 3300@16 lxz right at the amp to get rid of hdd whine at startup.
no problem running full volume with this 40x2 amp on a cheap dell desktop box.