CCTV cameras: single PSU or individual PSUs ?

[budm]

Re: CCTV cameras: single PSU or individual PSUs ?

But how about "How would you deal with initial power on?" as eccerr0r pointed out?
That relay circuit also needs to have hysteresis.

[Dannyx]

Re: CCTV cameras: single PSU or individual PSUs ?

ATX PSUs? Reliable? Ever looked at this website?

Yeah, like I said, I'm sure there ARE good ATX supplies, but only high-end ones. I'd dare to say my Corsair HX1200i is amongst them, since I can't imagine that thing would fail on me like a Deer, a Premier or a Delux, would it ?

[Retro-Hipster]

Re: CCTV cameras: single PSU or individual PSUs ?

That would depend on what the latch circuit is. if you're talking about the simple circuit with the relay then just turning on the primary PSU would click the relay on. Since the relay on. If the primary psu turned off, the so would the relay, switching the power to the secondary.. in terms of what could be used as a latch, you could do this with several things. You could do this with a relay and A switch for instance. ( press the switch to turn on the relay. The relay then powers itself through the output.) Give me a sec and I'll do a quick schematic. I this this could work.. You know. As a manual reset sort of deal. Haha

[Curious.George]

Re: CCTV cameras: single PSU or individual PSUs ?

(Still have a decent Bench supply, but meh.)

I have a rack-mountable triple supply that is digitally programmable. Its handy when I'm dealing with something "unknown" as I can type in voltage set and max current limit -- then monitor the voltage and current without having to drag out a meter to see if the "unknown" is, perhaps, toast!

Most of the time though, the PSU's I deal with are just from old pc's. Because I'm "the boss" I worry that taking server type hardware home would set a bad example. (We often sell our old server stuff to reseller types.)

We break-down servers and other bits of kit -- power supplies just get tossed into a Gaylord. So, fish through the Gaylord for something that "looks about right" (chances are, it's perfectly functional).

Biggest problem is dealing with the edge connectors that are commonplace on enterprise kit. Solution is just to solder directly to the fingers. Attached pic of the supplies I use to test powerchairs -- "(BIG) battery eliminators"). Anderson connectors are common on the chairs (high current rating, ease of connect/disconnect)

[Retro-Hipster]

Re: CCTV cameras: single PSU or individual PSUs ?

Okay! I drew up the schematic in everycircuit to try to explain this a little bit better. there are some limitations to the layout capabilities of everycircuit so it's a bit of a mess.
https://netorgft4619478-my.sharepoin...RsPjNMNzawY1hw

For an explanation of how the circuit works you can watch this video I made.

https://youtu.be/cxZXUr33Ic8

[Retro-Hipster]

Re: CCTV cameras: single PSU or individual PSUs ?

Ah.. It posted my post twice. :/ also, i have been messaging using my phone.. It seems that it has auto corrected some stuff. :| oh, also, i didn't notice that the schemaic I posted had 16v on one of the supply voltages... That should be 12v..

[eccerr0r]

Re: CCTV cameras: single PSU or individual PSUs ?

Ah... it would be more interesting when the supplies are symmetric to each other, which is what redundant server PSUs generally are.

[Retro-Hipster]

Re: CCTV cameras: single PSU or individual PSUs ?

AH, yeah, honestly this whole thing just stemmed from the thought that you could do a pretty simple active/passive failover with a relay and a few support components. ^.^; I didn't even really have an intention of drawing up a schematic, but people were asking some questions about it. (I certainly didn't intend on Hijacking Danny's thread.. SORRY DANNY!) Frankly, under any normal circumstances, I would probably just use oring shotky diodes on two supplies or use a couple of mosfet's as a stand in's. If I needed fancier I'd just go with mosfet's and a purpose-made IC with overcurrent/undercurrent and low/high voltage cuttoffs...

[Dannyx]

Re: CCTV cameras: single PSU or individual PSUs ?

Yeah, well it's no big deal - good ideas are always welcome and the best one are those which come at random and completely unrelated

I'm always on the lookout for a good project, PSUs included, so I never pass up a good dumpster dive, although our joint doesn't seem to be throwing out stuff all that often and most of it is useless anyway. We do have some servers around, so the possibility of coming across a PSU like that is possible, but just barely, because it's unlikely to still be functional at that point...hence why it's in the dumpster behind the building, where I usually like to stroll and "window-shop"