Christmas Light Pixels are unique in the fact that we can control them via a computer…but not directly.
While our computer will put out a DMX, Art-Net, or e1.31 (sACN) type signal, our pixels are not able to understand that information directly. We can’t just plug them into the computer via USB!
Pixels need the information simplified for their use.
What is a Pixel Controller and How Does it Work?
At it’s simplest form, the pixel controller takes the data from the computer (usually running a sequencer program like xLights or Vixen, or a Rasberry Pi running FPP), and converts it into a format that pixels can use.
This “format” may be a variety of different protocols that may use either three or four wires to communicate the signal to the pixels.
The most important thing to understand when looking for a controller is that you need to match your controller to the type of pixels (the protocol) that you have bought or are planning to buy.
There’s nothing worse than buying a controller that’s not compatible with the pixels you bought!
As I mentioned before, it’s generally a safe bet to go with WS2811, WS2812, WS2813 or similar pixels. Most controllers will work with these types of pixels, and they are the most popular type of pixels out there.
Other Things Pixel Controllers Can Do
Pixel controllers also can do a variety of other helpful things.
They can set a maximum intensity level for each string of pixels that are connected, and they can also do some fancy configuration to assign the exact data that you want to the exact lights that you want… especially if you didn’t wire everything the way that you intended when you first set up your software!
Often, the pixel controller that you buy will have multiple ports. This will allow you to drive multiple strings of pixels from that pixel controller.
Each string of pixels will have a maximum pixel count, usually 170, 340, 680, or 1020+ pixels.
Pay attention to this closely when you buy your controller – it will greatly govern the number of lights you can control overall!
Also, know that more is not always better – a bad pixel at the start of a 1000 pixel run hurts your show a lot more than a bad pixel at the start of a 340-pixel run! But, on the other hand, using the full output capability of your controller saves you money – so it’s a tough balance to debate with yourself!
Each string of pixels that you hook to an output of your pixel controller can also be configured as to what “Universe” and “Channels” it uses from your computer’s sequencing software.
What is a Universe and Channel?
We get these terms from the technology for controlling lights called “DMX”. DMX is the type of signal that has been controlling stage lights since the late 1980’s, and is quite good for a lot of reasons. (Dive deep into DMX here)
Each controllable “Channel” of DMX generally runs 1 function of a light – for pixels that is red, green, or blue.
512 Channels make up a DMX universe. When you run out, you need to start a 2nd universe (or 3rd, 4th, etc).
Back in the 80’s, the architects of this protocol probably intended for large shows to only have a small number of universes. But with LED’s, pixels and moving lights, it’s very easy to get into MANY universes of DMX.
For that reason, the stage lighting industry created Art-Net and sACN (known in the Christmas light world as Art-Net and E1.31), which are both built off of the building blocks of channels and universes.
And that is why we split up our signal to our pixels into blocks of 512 channels, called “universes”.
Each pixel needs to use its own channels, and channels work sequentially in universes. A single port of a pixel controller can output multiple universes to control lots of pixels.
For each port, most pixel controllers will also provide some power to the pixels via a power supply that you connect to power them all.
There are a lot of pros and cons to powering pixels from the controller versus from an external power distribution board, and we go into that here.
What Types of Pixel Controllers Are There?
There are two main types of pixel controllers that you will run into. The most common and older type that you’ll find is a standard pixel controller.
Standard Pixel Controllers
Just as I described above, these pixel controllers will take in the data from your computer via a network cable and convert it to pixel outputs, all within 1 “box”.
Controllers like these may have anywhere from 1 to 16 ports, and each port may be able to control anywhere from 170 to over a thousand pixels.
In the Christmas light world, these controllers usually come as a bare “board” that requires you to wire a power supply and the outputs yourself.
These connections happen via “terminal blocks”, or screw-down connectors that are attached via sockets to the controller board. These allow you to supply your own, preferred type of connectors to plug in your pixels.
Some pixel controller brands offer “Ready to Run” controllers that are built inside of a waterproof case with a power supply and output plugs pre-attached. This can be a time saver, but you need to make sure your pixels have the same connector as the controller before you buy!
Long-Range / Differential Pixel Controllers
The second type of pixel controller is a long-range style system. These are so much easier to work with, but I’ve got to give you a little background first so you understand why.
Why Long Range or 'Differential' Controllers?
Pixel signal, unlike the networked signal that drives the pixel controller, doesn’t like to run far distances.
In fact, depending on a number of factors, it may start to have problems after about 30 feet…. which is not very far when you think about the amount of wire that you’re going to use in your total display!
When the pixel signal starts to get weak, you’ll have problems like flashing, strobing, or completely unresponsive props.
The worst part about this is that your pixels can be working fine one day on a long wire, and then after the rain or a change in temperature things can go awry!
For that reason, it makes sense to go with smaller pixel controllers that are closer to each prop.
The downside to this approach is that there’s a lot of individual controllers that you have to configure and set up separately. It can become a bit of a networking nightmare if you’re not well versed in networking!
Some folks like to use “null pixels”, which are simple pixels that you assign in your sequencing software to always be off. These then amplify the signal so that the rest of your pixels work fine. Getting these right is a bit of guesswork, and a bit of a hack.
At the end of the day, it’s not as ideal of a workaround as a long-range controller, or multiple small controllers. But, I am getting ahead of myself here…
Long-Range, or “Differential” controllers, however, solve that problem for us.
They split the conventional pixel controller in half, with the processing done on a centralized board, and then receivers can be placed right next to your props for your pixel strings will plug into.
I also like to keep my differential controllers in a “safer”, more waterproof area, slightly further away from my pixels – under the carport or a porch works great and lessens the chance of any water getting in!
These receivers can often be hundreds of feet away from the central board. This is a win-win situation, and the great news is that these aren’t all that much more expensive than the regular older style of controllers.
Some examples of these types of controllers are the Falcon F48, and the Advatek Pixlite Long Range system. In the professional world, we also use the ENTTEC Pixelator system, but that’s a little pricey and has a lot of power and features that we generally don’t need when we’re doing Christmas lighting!
What Pixel Controller Do I Need?
Figuring out what controller you need is where the rubber meets the road.
If you’re just planning to do a small display, and you can keep your pixel strings with around a maximum of 30 ft between any two pixels, you can probably get away with a smaller 4-port pixel controller.
This is what I started with, and these controllers can often drive up to three to four thousand pixels.
However, if you’re considering going with a bigger display, and/or want the benefits of the long-range differential style receivers, then you’re going to want to buy a long-range controller.
For example, with the Falcon controllers, one of the most popular brands in the Christmas lighting community, I can get (2) 4-Port controllers for $250 at the time of this writing.
For that same cost, I can get one F48 controller that drives up to 12 receiver boards, that each can drive (4) strings of 680 lights a piece. With the F48, I can add (2) receiver boards, and the total cost is just under $250, for about the same functionality…plus expandability!
We could dive into the weeds on this comparison, as you may have noticed that the two 4-port controllers can drive a few more pixels.
On the other hand, the Falcon F48 controller gives you that centralized processing, and easy setup with the receiver boards. Plus, you can expand your show as time goes on very inexpensively by just buying more receiver boards (up to 12).
So, for this reason, I recommend most people begin with a long-range or “differential” style pixel controller if you’re buying from scratch.
It’s how I’ve used pixels most in the professional world, and the little cost increase far outweighs the downside of the standard type controllers – the length limit on how far the WS2811 signal can go!