Wiring Setup - Power and Data over 4 Core Wire
I'm not an electrician, an expert in electrical things, nor do I have any training or degrees to qualify me as such. ;) I'm just a guy who figured out what works for his display. Take this information as such. If it works for you, GREAT! I've accomplished what I set out to do. If you see a problem with what I'm doing or have a question, please e-mail me. I'm always excited and willing to learn something new. I can't assume any responsibility for the outcome of your project if you chose to follow these instructions, or the fallout thereof. If you think I'm an idiot, kindly smile to yourself, click your "back" button three times, and have a nice day!
These are the two different types of modules/nodes I started with. Different modules work better for different applications. The 5050 SMD modules on the right are great for back lighting coro, spelling out words, and any kind of wall wash or flood light applications. They don't, however, look like christmas lights. The through-hole LED Nodes on the left definitely look more like mini lights and they are WAY brighter than the standard half-wave strings you can buy at the big-box stores, but they aren't completely perfect either. They need some additional waterproofing and have other needs I plan to cover in a separate section. To begin, you need to identify which LEDs you'd like to use. In this case, both are 12V, booth have common positive leads, and both are non-digital meaning the entire string acts together. I'm using the modules with the wreaths from my other How-To but the nodes will be used in my trees just like regular mini lights or conical LEDs.
Here are two different DMX decoders that are affordable and commercially available. The decoder on the left is the one sold by HolidayCoro, and on Ali express. They can be pre-addressed to whatever channels you order, they are water resistant, and come with wired leads ready to solder onto. The addresses can be changed with free software available online, a link to download the software is supplied when you purchase the $20 DMX dongle needed to do it. This dongle can also be used with several software programs widely used in the lighting community. The controller on the right is slightly more expensive and does require some kind of waterproof enclosure, but the dimming is almost perfect and the address is set with an on-board dip switch. I love using it for testing as it is easy to re-set the address and has screw terminals to attach the modules. This lets me connect it to different kinds of modules/nodes and even run more than one at the same time.
Each of the strings or display elements has a set of "pigtails" that allow it to connect to the network of other strings. Each set has one male and one female plug to allow them to be daisy chained into a network. By running power and data together, I've simplified the setup allowing literally any element to be re-located simply by unplugging it from it's previous location, and plugging it in at it's new location. As the display grows this becomes more important!
After experiencing multiple failures with my pigtail setup during the 2011 christmas season, I decided there had to be a better alternative. Now, I loved the price point of using cat5 and the couplers were something that was familiar, but they just didn't hold up. My first discovery was that under any damp condition, the plating metal inside each of the couplers would wear off. Once the copper conductor was exposed it almost instantly oxidized causing shorts. After trying di-electric grease slathered on every coupler I was still experiencing failures, not a lot, but enough. Going forward I'm scrapping that approach in favor of the 4 core waterproof pigtails. The wire is heavier gauge allowing more current draw and they are available at a great price, not to mention they are ready to go, no "assembly" required. As I put more and more time into building and programming the display, the time factor is something that has progressively become more and more valuable.
In order to keep things simple and to keep my extensions interchangeable, I'm using only 4 core wire and waterproof pigtails. 4 wires going into each controller, 4 wires going out. By using the pairs illustrated above I've made it impossible to ever accidentally run power back down a data wire. I've decided not to use the "ground" wire in the DMX data pairings because in my case, the open DMX USB adapters don't have one anyway. I am sticking to the uniform and traditional pairings that a male plug is the incoming wire and the female plug is the outgoing wire. If a string or element were to ever be plugged directly into a power/data wire it won't light and it won't fry the string. As I stated earlier, on the incoming side I'm actually using a pair of pigtails, one male and one female to allow them to be daisy chained. The photo below illustrates a finished DMX decoder with all necessary pigtails in it's finished condition.
Another design change from my setup last season is adding the waterproof couplers between the decoders and whatever string or display element it is controlling. If I soldered the decoder directly at the end of the node string or modules then I have to bring in the entire string or pole, or whatever it is inside if something goes wrong with it. The same holds tru for programming them. In order to make it simple and easy, the extra coupler allows me to completely remove the decoder, replace it, or re-program it without messing with any of the installed strings or elements. Is also allows for the addition of extension cables between the decoder and whatever it is controlling. This works great for my trees where I can run one decoder at the base of the tree to minimize cabling between each tree, then just run a single extension up to the RGB node strings. I'll be using the same waterproof pigtails at the end of the node strings, modules, floods, etc. In this case, my wire colors match. White is the common 12v positive, and the red green and blue are the neutral wires for their corresponding colors. Not all nodes or modules are the same. I've had red wire light green LEDs, blue wires for common positive, etc.
In the case of the 5050 modules I'm using for the wreaths, the common positive is yellow, the blue wire is blue neutral, but the red and green wires are switched for their respective colors. Test your nodes before you solder them to make sure you have the correct color wires controlling the appropriate color LEDs.
Most of my trees are fairly new as we just built the house in 2010. As a result, none of them are more than 10' tall so I'll be using string extensions between the strings and the decoders. I have made my own in the past, using a standard 14 gauge 4 core speaker wire soldered directly to the pigtails but for next year I am working with a manufacturer to have these made. After soldering each lead from the pigtails to their corresponding wires I run about an inch of heat shrink over the soldered joint. After each is covered in heat shrink I pull the wires together, coat them all with liquid tape, the slide down a 4" section of 8mm heat shrink over the whole thing. Again, my testing has shown this to be the most water tight connection so far. With our brutal Kansas winters snow, ice, and moisture is a real concern.
MODIFYING THE ENTTEC OPEN DMX USB
To begin we want to disassemble the Enttec Open DMX USB. This is pretty easy to do, it's just 4 screws that need to be removed with a screwdriver. Be careful not to strip out the threads in either the 5 pin XLR jack or the small holes on the sides of the base.
In order to accommodate the new 4 pin waterproof pigtail we need to drill a 3/8" hole directly above the USB port in the outside metal shell. I used a standard metal drill bit on my cordless drill. Use a punch to mark the center and drill away! After you've made the hole, clean up any burrs or shard edges, I used a dremel to get rid of the biggest ones, then fit a small rubber grommet in the hole. The ones I used I found in an auto parts store for a few cents each. Our new pigtail will run through this hole.
Next we want to prepare the pigtail and the XLR jack for soldering. Cut off the blue and black power wires flush on the pigtail. We don't want any chance of 12V power shorting something in the Enttec. I coat the ends with a little liquid electrical tape. Next we want to "tin" or apply a small ammount of solder onto the center and first pin to the left of center on the back of the 5 pin XLR jack. Tinning both the wire ends and the pin connectors with solder before putting them together will make joining them later much easier.
Before soldering the pigtail to the XLR jack, thread it through the rubber grommet in the case. Line up the red wire (This is our DMX Positive Wire) with the center pin, pin #3 in the XLR jack. Touch the tip of your iron to them both and the tinned surfaces will fuse. Next line up the green wire (This is our DMX Negative Wire) with the first pin left of center, pin #2 in the XLR Jack. Again, just touch the tip of the iron to each and they will fuse. Next, align the board in the housing base and place a zip tie around the pigtail wire. This will prevent the wire from pulling through the grommet or pputting strain on the soldered joint.
Re-assemble the Enttec Open DMX USB case, carefully replacing the screws in their respective holes. The two longer screws hold the XLR jack to the face, the two shorter screws re-assemble the two halves of the case. That's it! The Enttec Open dongle can now connect via the traditional 5 pin XLR jack it came with OR the new 4 core waterproof pigtail setup! Doesn't get much simpler than that. For purposes of testing and assembly I often use a 12A benchtop supply, one I made from an old PC power supply. To make it easy to power up, test, and program the DMX Decoders from HolidayCoro.com, I wired an additional pigtail directly to the power supply.
MODIFYING THE LYNX DMX USB
One of the best parts of this hobby are the talented and intelligent members of the user community. So many of the best and most innovative software and hardware developments come directly from the user community. One of the best testaments to this type of this development is the LYNX Line from RJ at DIY Lighting Animation. This intelligent DMX dongle (similar to the Enttec Pro) can be built for under $50! I orderd PCBs to make 4 of the dongles and didn't quite get it done in time for 2011. With some down time and planning available I decided to finally make the push and get them built. I was amazed at how easy it was. RJ has a wonderful tutorial that walks you through step by step construction so I won't repeat that here. I just want to show how I added a plug for my 4 core pigtail setup. Again, the important thing to keep in mind is that it's just 4 wires. Two for power, and two for data. That's it.
The LYNX Group buy makes available this simple enclosure. It's basically a very common PVC project box that has two square holes cut at one end for the incoming USB and outgoing Cat5 jack. I don't want to lose any part of the original design, similar to how I did the Enttec, I just want to add the 4 core pigtail to the setup. Because I had the room in this instance, I decided to fit the entire plug into the box so that I can simply and easily screw on an extension or blender directly to the dongle. I took a very simple approach to this, starting small with a drill then slowly cutting away a hole until I got a nice snug fit around the plug. A few small dabs of super glue will hold it in place. In the pics you can see that I've already removed the black and blue power carriers, all we are concerned with is the red and green data carriers.
Here you can see the fully assembled LYNX DMX Dongle minus the PIC (still waiting to program those). The data wires just loop around to the back of the board where we tacked them. All that's left is to secure the cover!
Plugged in and powered up we now have a DMX LYNX Dongle with standard USB input and outputs to BOTH our 4 core waterproof pigtial format as well as the traditional Cat5 RS485
BLENDERS and POWER INJECTORS
VIDEO WRAP UP