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Thread: Box to power various componenets without a motherboard?

  1. #1
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    Box to power various componenets without a motherboard?

    Hi everybody,

    I am hoping to utilize CarPC parts & mentality to construct a customized enclosure tethered to and existing PC.

    This box will serve as a "pass through" box. It will not be a computer in itself; more like and external module, housing a few key components.

    At the end of the post, I will give some background about my project, but for now- I will just get straight to the point. I have linked to my proposed parts.

    What I require is an enclosure that provides power to the following internal components:

    Touch Screen LCD panel (connecting to external source PC via DVI for display & USB for touch interface)
    2 x POE injectors (standard Ethernet in | powered Ethernet out)
    2 x SATA SSD (receives standard SATA cable from external source)

    So in essence, it is simply an external monitor with a couple of hard drives and POE injectors thrown in.

    For simplicity, I would like to use DC/DC power supply in the box (making it easier to power via laptop battery pack)

    Assembling such a device without using a motherboard poses challenges which are beyond me- this is why I am here asking for some help.

    My main concern is how to actually provide power to each of the enclosed components. I can use a paper clip to trick the power supply into thinking it's connected to a motherboard, but...

    Is it possible to somehow hack the power supply to run power to each of my above components without needing a motherboard??


    Also, as I am no expert in any of this, if anyone has any other concerns, please let me know!



    __________________________________________________ _________



    Background:
    (read on if interested)

    As part of the open source cinema project Apertus, I am building a stereoscopic 3D camera rig, utilizing 2 of the open source Elphel 353 cameras- running open source software. You can follow / contribute to the project at apertus.org

    The cameras are network controlled and powered via POE (power over ethernet)
    These are very high resolution / high quality camera's; and as such- they require a powerful PC to display both video streams.

    So I need to develop a box that attaches to the camera rig- but serves as a secondary monitor for the main host PC. This box also serves as an enclosure for 2 SSD's that attach to each camera over SATA; and also a POE injector to provide power to the cameras.

    By unifying all these peripherals into one box, not only do all the connections become manageable- but powering the components becomes much more elegant as well - The ability to connect a mains / battery pack to the whole box, rather than attempting to connect each component individually!

    Here is a rough digram of the box:

  2. #2
    Raw Wave
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    What is the power consumption (voltage & current) of the cameras?
    By POE do you mean that power thru the ethernet connection (as opposed to controlled...)? I ask in case the CAT-x can't handle the power.

    And I presume you control the power to the box, hence the power to the PC that in turn controls the devices.
    You need to specify such things, and if you want the AC-DC co-hosed (I suggest not) rather than having a single DC input or 2 DC inputs (DC from mains & 12VDC) with (say) AC priority.

  3. #3
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    Hi OldSpark, thanks getting back to me.

    The Elphel Camera accepts 12-36V DC power (peaking at around 5w)
    more info on the camera here
    more info on the camera power supply here

    The camera is both controlled and powered through the single power injected CAT 5E ethernet.

    total power load of components
    Liliput 7'' (10V-11V) 8W
    Elphel (12V-36V) 5W (x2 = 10W)
    Eidusa INJERCTER-PS48 (48V) 12W (x2 = 24W)
    Various SSD's >5w (x2 = 10W)

    Maximum total load = 52Watts

    I would like the box to be powered independently from the host PC with a single DC input.
    (I can then use an AC adapter from the mains, or a laptop battery pack to power it.)

  4. #4
    MySQL Error soundman98's Avatar
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    for the ssd's and screen, a modified atx psu would work fine--i think the m1, or m3 series 'might' be ok-- in your case, the noise they produce might not be acceptable(there is a thread in the power supply section on this). technically, the screen should work on unregulated 12-15vdc, but in most cases, the screen will have longer life with regulated power..

    the eidusa POE injectors--are these the ones that you are thinking of using for powering the cameras? i don't see any power input specs on some of the boards, so can't really comment on them.


    also something i didn't really see in your first post:

    does this setup need to be mobile(hence lightweight+compact), and what kind of space requirements does this project need to have?

  5. #5
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    Yes, the eidusa POE injectors are what I was thinking of using, But I am open to a different product- should it be better suited.
    (I have contacted the camera manufacturer to determine if the above mentioned would be suitable)

    Regarding form factor, I should have been more specific, Yes the box needs to be portable.
    Im thinking that it would be ideal to use a "2nd Generation Bybyte Double Din Nano-ITX carputer enclosure" to house all the components, including the screen.
    Being lightweight and quiet are also desirable factors.

    Ideally, the internals of the box, including power supply- would all be DC power, and I would connect an external power brick to the device which converts from mains power to DC.
    I want to use a CarPC power supply because they are silent, and will perform better when the device is connected to battery, rather than main power.

  6. #6
    Raw Wave
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    I just bought a cute adaptor for AUD$29.
    10-14VDC input or 110-240 50/60Hz AC input; 100W output with 5A from 12-20V or 4A from 22-24V (switch selectable outputs of 12, 15, 16, 18, 19, 20, 22 & 24V) and a 5V/1A USB output. The cig socket has a 3AG glass fuse (10A?)

    It's best pictured at alibaba:441043930:-100w_universal_notebook_power_adapter though that doesn't show its AC lead nor the tip selection - but look here, here or here for an idea, though mine came in a blister pack.

    For 100W it's small - a mere 115x65x30mm (4.5x2.5x1.25") - and seems robust, though I haven't yet tried it. But I'd expect it to handle 60W without problem.
    Not that I know how it handles BOTH DC & AC inputs together, but it should take the AC as a priority unless they assume one OR the other, but NOT both. (Maybe I'll open it up...)


    That's just FYI. It's rare that I see a combined AC/DC input unit so cheap - I was rapt getting a DC input with 15V-24V 45W output for $25 ~half a year ago.

  7. #7
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    I have one of those OldSpark cot it from citysoftware when it was on special. Gets a bit warm on AC and noticed it created interference in a commodore's radio when I tried charging my laptop with it But didn't get so warm on DC..

    Could you just use a POE switch? We used one at work for some sensors that got their power over ethernet..
    For memory something like this:
    http://www.netgear.com.au/au/Product...itches/GS110TP

  8. #8
    MySQL Error soundman98's Avatar
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    lol, i just used that same switch for 7 ip camera's for one of my customers...


    here's the problems i see so far:

    psu for hdd/screen:

    the m1, or m3 are the most desirable due to their very small form factor.
    but they are not desirable due to the high chance that they will introduce noise into the system-- which could affect picture quality..

    for this, i would recommend a dsatx, or opus-series psu, because these have much less noise issues. the problem though is that these are much larger, so they would be harder to fit.


    POE injectors:

    this is potentially the toughest issue.

    i could not locate any POE injectors that would upconvert 12/24v dc to the required 48vdc that POE uses.

    so because of this, i believe the secondary power option-- to power the cameras with 12-24vdc would be your best option.




    because the cameras consume about 5w(according to what you said before) the dsatx, or similarly-rated opus should also be able to provide plenty of regulated power to the cameras as well.

    imo, the external battery pack should be rated for 24v, so you can get slightly longer run times then attempting to use 12v batteries.

  9. #9
    Raw Wave
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    Quote Originally Posted by soundman98 View Post
    imo, the external battery pack should be rated for 24v, so you can get slightly longer run times then attempting to use 12v batteries.
    Excluding efficiencies (where higher battery voltages are more efficient and lower current), it's the total of Volts x AH.
    Since a 24V (or 48V) battery is 2 x 12V batteries (or 4x), you have as much energy (V x AH) as all the batteries in parallel.
    Not that paralleling batteries is good - much better to have them in series - but the point is that one bigger 12V battery is better than multiple - eg, 1x15AH or 18AH instead of 2 x 7AH etc in parallel. (No paralleling complications; probably a cheaper battery that will last longer; no need to replace all batteries in case one fails.)

  10. #10
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    Hi guys,

    thanks for all your ideas!

    To simplify things, I can completely avoid using a POE card. I have been told by the camera manufacturer that I could simply splice some power into the Ethernet, by way of a 2 pin Molex Microfit 3.0.
    the two non-signal pairs are separated from the RJ45 connector, extended another 10cm and a 2-pin Molex Microfit-3 connectors are attached.
    So there's a solution for the POE.

    Now I'm hoping to complicate things a bit further, by also putting a gigabit switch inside the device!

    So things that need power from the PSU.

    2 x 2-pin Molex Microfit-3 connectors (for the cameras)
    2 x SSD's
    1 x Dlink DGS-1005D switch
    1 x lilliput 7" screen

    I like the suggested dsatx PSU, and with enough creative packing, I should be able to fit the above components into the Bybyte enclosure!

    What I completely do not understand is how to physically wire everything up!
    What adapters and cables are needed and what do they connect to!?

    (As an example of my ignorance)- I am correct in assuming that I could connect all the devices to the PSU via Molex's with appropriate adapters? If someone could assist me here, in layman's terms; I would be very grateful!

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