DMX + Power over CAT5 Distributor

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David_AVD

David_AVD

Grandpa Elf
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This controller is now available. Further info to be found here




OK, here's another project I'm working on. It a companion to the DMX to SPI (pixel) controller board.

This one has 4 DMX inputs via RJ45 connectors. Each DMX input is replicated to two outputs, also via RJ45 connectors, so there are 8 DMX + power outputs all up. These output connectors also have pins 3 and 4 used for power injection.

Please note that the DMX pinout is the standard ESTA approved one and is not compatible with LOR, Rennard or your uncle Frank's weirdo pixel board. Please don't ask me to make it compatible - it's not going to happen. ::)

This new board also accepts a DC voltage input in the 12V - 36V range. This is the voltage that is fed (via individual fuses) to the RJ45 output sockets. The idea is to feed DMX and power to small controllers via CAT5 cables. These new controllers will have a DC-DC converter on-board to drop the 36V down to the 5V or 12V that the pixels require.

Using 36V means that we can send approx 50 Watts of DC down each CAT5 cable while keeping the current (and cables losses) right down. You can use a lower voltage (down to 12V), but the lower you go, the more losses you get. So, 36V would be great, but 24V would also be good.

Via some jumpers however, you can reconfigure the board to do:
I/P 1 to O/P 1+2, I/P 2 to O/P 3+4, I/P 3 to O/P 5+6 and I/P 4 to O/P 7+8 OR
I/P 1 to O/P 1+2+3+4 and I/P 3 to O/P 5+6+7+8 OR
I/P 1 to O/P 1+2+3+4+5+6 and I/P 4 to O/P 7+8 OR
I/P 1 to O/P 1+2+3+4+5+6+7+8 OR
I/P 1 to O/P 1+2, I/P 2 to O/P 3+4 and I/P 3 to O/P 5+6+7+8

Oh, each of the output fuses also has an associated "power good" LED so you can spot a blown fuse easily.

Anyway, I'm about 50% done with the PCB design. Comments welcomed.
 
Forgive me if I'm wrong, will this new circuit board come into a mega-tree [for example 40 strings of 50 pixels] with 2 cables running around the circumference at the base of the tree [1 DMX data and 1 power up to 36v] and with a 40 of the pending DMx to SPI circuit boards you a working on run the whole tree?
 
Hi Eric,
That's not quite the intended use for my new boards. It's more for where you have a several small pixel strings spread out over a distance.

I think larger scale display items such as mega trees would be better served by a different approach. It would depend on what hardware you already have.
 
I have no hardwear at all just knee deep in WS 2801 pixels (3000 so far) for my new mega tree the rest of the display will be LOR DC and Ac I have already and will be controling via DMX and a DR4
 
OK, the PCB design is now complete, with final critique from the ACL chat gallery! :D

The overall board size is approx 114mm x 102mm (4.5" x 4")

So to recap:
  • Pluggable dual DC input (12V - 36V)
  • 4x DMX inputs (RJ45)
  • 8x DMX + power outputs (RJ45)
  • Selectable in/out DMX routing
  • 2A mini blade fuse per output
  • Power available LED per output
  • Field replaceable RS485 (DMX) chips
  • On-board regulator for DMX chips
  • 5V power LED
  • RJ45 pin-out charts on silkscreen
 
I've added an LED for each DMX input to show activity. Also added "link out" and "ext in" connectors so you can link two of these boards together (with small cable) with just one DMX input.

Should have prototype boards back within 2 weeks.
 
Nice approach to getting lots of signal and power down a single cable.

Of course, this means that there may be lots of 36V or 24V power running around the yard, as opposed to 120V here in the US.

And to think that I have a few 24V power supplies sitting around that I might have to swap for 36V ones.
 
Sorry guys, I completely forgot to post the picture of the finished product:

APC707.jpg


I'll be working on the other P-DMX projects again soon. :)
 
Looking good David, when we have some dmx->spi controllers with dc-dc converters I will be able to use these for my 150 channel light poles/stars


Neil
 
After playing around with this board, I've decided to redo the PCB layout. This is to fix some component clearance issues and implement a couple of slight improvements.

The power and DMX indicator LEDs are now next to their respective RJ45 sockets. There's also a bit more room around each RJ45 socket and I've changed the input power connector to a 30A screw type (was plug-in).

The new PCB is approx 110mm x 145mm (4.325" x 5.7") and will now screw straight into the mounting points of a Jaycar HB6129 plastic enclosure.
 
Just received word that the initial batch of PCBs are on their way to me, so should have some built to show at the BNE meet.
 
This controller is now available. Further info to be found here



great to see some of your projects coming to fruition, i look forward to seeing them at the Brisbane mini
 
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