Arena 5 made outputting to LED strips a piece of cake. Arena can sample the video pixels and output RGB values to the strip via DMX.
DMX is great, because it’s been around since forever and has become an industry standard that most devices will be able to work with.
The downside is that it has the concept of ‘universes’, which is basically a fancy term to describe all the lights that are on a single control line. A universe is limited 512 DMX channels. This is fine for conventional lighting setups, and was more than enough when the protocol was established way back in the eighties. But with every RGB pixel taking up 3 channels (1 for Red, 1 for Green, 1 for Blue), you can only control a maximum of 170 pixels per universe. With LED strips becoming super cheap and more and more high-res, building anything fancy can quickly require 10 or more universes.
In the past, we’ve always recommended USB to DMX devices to get started with DMX. These are great, because they’re simple in operation and relatively cheap. The trouble is they only output 1 or 2 universes at the most and don’t work via USB hubs. So using USB, you quickly run out of breathing room.
A great alternative is Art-Net. Art-Net lets you send DMX signals via a regular network connection. Especially when working with computers, Art-Net is awesome, because you can use the same Ethernet cable as you use to connect to the internet. Instead of connecting to your modem, you connect it to an Art-Net to DMX device, which will convert it to a signal that your DMX light will understand. Using a regular network switch or router, you can add as many Art-Net devices as you like, so you’re not limited by the amount of ports your computer has.
So the race is on to find affordable, reliable Art-Net to DMX devices. We took a look at Showjockey’s selection. Showjockey
is a manufacturer based in China (and they have many interesting gadgets
aside from Art-Net stuff too!). We got a chance to play with their 4 universe SJ-DMX-E4 and the crazy 16 universe SJ-DMX-E16.
The Showjockey material comes nicely packaged, but is very spartan when it comes to documentation. The package does contain some booklets, but these are just advertising material for their other products. Since setting up Art-Net can be a bit of a black box, this can be a deal breaker, especially since the Showjockey devices have a somewhat unique setup method. It would greatly benefit from a manual, or maybe just a short setup guide.
An Art-Net device is essentially a network device, so it needs an IP address in order to let the sender computer know where to send its packages. Unlike a computer, Art-Net devices generally are programmed to have a fixed IP address. We were informed that all Showjockey devices default to IP 192.168.1.200 and subnet mask 255.255.255.0. Since our office network expects all IPs to be in the 192.168.178.x range, we had to jump through some hoops to get the devices to work.
On the SJ-DMX-E16, things weren’t so complicated. It has a little onboard menu display where you can set things like the IP address, and once we figured that you need to turn it off and on again
to have these changes take effect, we were blasting pixels in no time.
As long as your Art-Net device is in the right IP range, Resolume will broadcast to all IPs in that range, so no further tech setup was needed. Our test setup consisted of 12 8x8 RGB LED tiles. With each tile needing 192 channels (8 * 8 * 3), we were stuck to 2 tiles per universe. We ran a single Ethernet line to the SJ-DMX-E16. We then ran the first 6 DMX outputs to each of the 2 tiles in each universe, with 10 outputs still to spare.
We had a bit more trouble on the SJ-DMX-E4. This one doesn’t have an onboard menu, so you first need to set your computer’s ip to the 192.168.1.x range (we used 192.168.1.10) and connect the SJ-DMX-E4 directly to it with an Ethernet cable. At this point, you can access a setup page by typing 192.168.1.200 in a browser. Here you can change the IP address, the name the device has on the network and things like the universe and subnet offset. Once we set up the IP correctly and power cycled the little rascal, this device was also working correctly.
Another thing you can set via this page is the universe and subnet offset. This is really useful when you want to work with multiple devices on the same network. For instance, we can use both devices in the same network, simply by setting the first device to start on subnet 0 and the second device to start on subnet 1. This way, any Lumiverses patched to subnet 0 will always go to the first device, and Lumiverses patched on subnet 1 will always go to the second device.
All in all, the beauty of Art-Net is that once you actually have it working, it’s pretty rock solid. You can hot plug power and DMX cables, and the LEDs will just pick up right where they were. The Showjockey devices work with a web interface, which is a great way to configure the device without the need for additional software. It’s also worth to note that the SJ-DMX-E16 can be configured both via the onboard menu and the web interface, and changes on one end will be picked up on the other.
The downside of the Showjockey boxes is that they’re a bit of a black box without a setup guide. Especially when you have to jump through some hoops if your IP is not in the same range initially. They have some videos online
showing you the process, but these are hilariously unprofessional. Also, there’s a status LED on the device, which we’ve never seen change from red. It would be nice if that gave some additional feedback on what’s going on.
On the upside, they’ve been very responsive to our requests, and can’t be beat on price: the 4 universe SJ-DMX-E4 is $196, the 16 universe SJ-DMX-E16 is $600, and there is also a 2 universe SJ-DMX-E2 for $120.
More info via http://www.showjockey.com