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DMX Splitter

Discussion in 'The Development Lab' started by David_AVD, Sep 10, 2011.

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  1. David_AVD

    David_AVD Bite my shiny metal ass!

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    As people add more DMX controllers to their displays, the subject of DMX splitters comes up again and again.

    There's quite a few DIY DMX splitters scattered around the Internet, but a lot of them have issues such as:
    • No pre-etched PCB available
    • Incorrect receiver implementation
    • Poor general design
    • 240V (or 110V) required
    • No RJ45 connectors
    If there is interest, I can design a DMX splitter that overcomes the above issues. It could be a simpler non-isolated design, an isolated input design, or a fully isolated design. A wiki page outlining the different types of DMX splitters can be found here.

    Isolation adds a fair bit of cost to a DMX splitter, so it may be that two designs (non-isolated and isolated) are done. Anyway, over to you for discussion. :)
     
  2. Gordon Lights

    Gordon Lights New Elf

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    Great idea. Any thoughts on approximate costs?
    Fabian
     
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    David_AVD

    David_AVD Bite my shiny metal ass!

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    The costs would vary a lot depending on number of outputs and whether or not it is an isolated design. How about we start with the requirements and I'll see if I can pluck some figures out of the air as a guide?
     
  4. Gordon Lights

    Gordon Lights New Elf

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    Unless I'm missing someting, I would expect a fairly linear price curve per split. I would imagine in most cases a 4 way and maybe an 8 way split would be the most practical. Personally I would always vote for a fully isolated design.
    Fabian
     
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    David_AVD

    David_AVD Bite my shiny metal ass!

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    OK, I see what you mean Fabian. I'll work out some rough estimated prices for the input and output sections this week.
     
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    David_AVD

    David_AVD Bite my shiny metal ass!

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    The raw parts cost for the input section is about $4.50 for the input section and $9.50 for each output section. Each includes a small allowance for a portion of PCB.

    Normally the output section parts would be more due to the cost of the DC-DC converter, but I can get them for $2.50 + GST (100-up) at present. It's a DIL package so takes up a little more space, but if the price is right. We may even be able to "dual footprint" the board so it can take either type according to availability.

    I have not allowed for assembly labour, case, postage, etc in the above pricing.

    EDIT: I did allow for IC sockets and RJ45 connectors however.
     
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    David_AVD

    David_AVD Bite my shiny metal ass!

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    Started the schematic and PCB layout today.

    Would people prefer the RJ45 sockets to be straight (plugs in vertically) or right angle (plugs in parallel with PCB) type?
     
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    David_AVD

    David_AVD Bite my shiny metal ass!

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    I was thinking of R/A connectors myself so that two boards could be stacked to make an 8 way unit.

    As for a nice case, a DMX splitter like this would likely be going out in the yard, so would probably be best mounted in a sealed enclosure. No point wasting money on a fancy extrusion in that case I reckon.
     
  9. XDU

    XDU Full Time Elf

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    David, did you progress these splitters or was there not enough interest?
     
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    David_AVD

    David_AVD Bite my shiny metal ass!

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    Nobody really commented on the proposed pricing so I figured it was a dead dog. If there's interest I'm happy to proceed however.
     
  11. XDU

    XDU Full Time Elf

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    Pity, the pricing was pretty reasonable
     
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    David_AVD

    David_AVD Bite my shiny metal ass!

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    DMX works "most of the time" with crappy distribution methods and it seems folks would rather chase intermittent faults than spend some money to do it right. :p
     
  13. kevr

    kevr Full Time Elf

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    Hi David,


    I am interested in this as I have had problems getting the 240v transformers in the other post here


    If we could get a splitter that could run of a DC supply, 12v, 24v or whatever that we are using in the yard all the better. I paid about $30 US for my splitter PCB and gear from Mouser and then had to get them to NZ just as a comparison.


    Kev :)
     
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    David_AVD

    David_AVD Bite my shiny metal ass!

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    That splitter from RJ is a simple non-isolated one. I was aiming to do one with isolated input and outputs, but the complexity and cost does jump up a fair bit.

    Maybe there's room for both (non-isolated and isolated) projects?
     
  15. kevr

    kevr Full Time Elf

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    I did look at this one as well but only 120V.


    I am using a mix of wireless as well but still think a splattering of splitters around is a good idea. I use the TA200 enclosures for a fair bit of my stuff which are great boxes, if you can get the shipping down, they are about $3 US for the box.


    The one thing you find out pretty quick with this hobby don't get too hung up on what the bits cost because by the time it gets to the southern hemisphere it ain't cheap!!


    Mental note hide the next credit card statement.


    Kev :)
     
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