How to Troubleshoot Random Flashing in E1.31 Controllers (Updated for 2026)

Updated September 2026 for xLights, FPP and today's home networks.

From time to time customers report "flashing," brief interruptions of light output, or stuck pixels on their E1.31 controllers. We can't give one answer for every case because there are too many variables, but this post gives you concrete troubleshooting steps to track down the cause.

E1.31 (also called sACN), along with Art-Net, is just one part of a stack of systems that carries data from your sequencing software to your lights. Let's walk through each layer, from the lights up, and look at the likely causes and how to rule each one out.

1. Lights and power

Start at the bottom. Most E1.31 controllers have a built-in test mode that outputs a pattern straight from the controller, with no computer involved (check your controller's manual or web interface for its test function). This splits the problem in half: if the flashing happens in test mode, the problem is in the controller, lights or power, not the network or software.

Run the test at full white and watch for flashing:

• Flashing only at full white or bright, busy effects, but not on a single color usually means there isn't enough power for the number of lights.
• Minor under-powering shows up at the end of a run, where pixels drop below the voltage they need and glitch or go dark.
• Major under-powering makes the power supply shut off for a few seconds at a time due to over-current, and everything on that supply goes dark.

To check, set all pixels to full white and measure the voltage at the end of each run with a multimeter. A large drop from the start of the run points to a power problem. The fix is usually power injection or splitting the run; see our guide to lights, controllers and power.

2. The network

E1.31 controllers are devices on an Ethernet network, so the network itself can delay or drop data. Things to check:

• Wireless. If any part of the path is wireless (bridges, extenders, mesh, access points), switch to a wired connection for testing. We don't recommend running show data over Wi-Fi unless there's no alternative to a network cable. Wireless adds delay, loses more packets and is subject to interference.
• Multicast vs. unicast. E1.31 can be sent as multicast, which some home routers and mesh systems flood to every device on the network, including Wi-Fi. Setting your controllers to unicast (sending to each controller's IP address) in xLights and FPP avoids this and is the better choice for most home networks.
• A separate show network. For larger displays, many people put the show player and controllers on their own switch or network, away from household traffic.
• Multiple network interfaces. If the computer has both Wi-Fi and wired connections, disable the one you aren't using for the show. We've seen routing problems send show traffic out the wrong interface.
• Simplify. Where possible, connect the computer or FPP directly to the controller with a single cable to take the rest of the network out of the picture.
• Ping. Run a continuous ping to the controller and watch for dropped replies.

3. The show player

Most displays today are run by FPP (Falcon Player) on a Raspberry Pi or similar small computer, or directly from xLights on a PC. If you see flashing:

• Update FPP to the current release.
• Check FPP's output settings: the universes, IP addresses and unicast/multicast settings should match what's configured on the controller.
• To isolate the player, play the same sequence from xLights on a PC. If the flashing goes away, the issue is in the FPP setup or its network connection.

If you're sending from a PC, firewall and security software can inspect or delay outgoing network traffic, which can show up as random flashing. When troubleshooting, temporarily disable third-party firewall software to take it out of the loop. We also recommend testing from a dedicated computer rather than a virtual machine (such as Windows running on a Mac).

4. More than one program sending data

If more than one program is sending E1.31 data to the same controller, the two streams fight each other and the lights flicker between them. This happens more often than you'd think:

• xLights and FPP both sending at the same time (for example, xLights test mode open while FPP is running a schedule).
• A second show player, or an old one you forgot was still running.
• Light-O-Rama's Control Panel, if LOR is also installed. It can keep sending E1.31 data in the background even when the Sequence Editor is closed. To stop it, right-click the light bulb icon in the system tray and choose to unload it.

Make sure only one source is sending data to each controller.

5. The sequence

• Software updates. If a sequence worked last week and now flashes, and nothing in your hardware changed, the latest software version may have introduced a problem. Try rolling back to the previous version and re-testing.
• A bad sequence. Create a new, simple sequence from scratch, with nothing imported, that just turns everything on. If that plays cleanly, the problem is in the original sequence.
• Too much data. Displays now run tens of thousands of channels. If the player can't keep up, output can stutter. Test with a simple sequence or with some controllers removed to narrow it down.

The Test tool in xLights is also a quick way to send clean, simple patterns to one controller or output at a time.

6. Last resort: look at the packets

In rare cases we have to determine whether a problem is in the controller and network or in the software sending the data. For that we use WireShark, a free program that lets you see the actual data going to the controller, including malformed or out-of-order packets. It was the only way to prove the cause in the case shown below:

It's rare to need a tool like this. Your vendor should be able to help well before you get to this point.

7. Firmware

E1.31 is a simple protocol, but a controller's firmware can still have a flaw. Update to the vendor's latest firmware first. If that doesn't fix it, try moving things around: swap which universes go to which outputs and see whether the problem follows the output or the universe.

If you suspect the controller, send your vendor:

• A detailed list of the steps you've taken. Use specific references such as "output 1," not "the output."
• How the controller is configured (universes, channels, outputs) and what's connected to each output (pixel counts, etc.).
• A copy of the sequence that reproduces the problem.
• Details of your network: what's between the player and the controller.

The vendor knows nothing about your setup except what you tell them, so the more detail, the faster the answer.

Conclusion

E1.31 itself is simple, but there are a lot of layers between your sequence and your lights. Start at the bottom, rule out each layer, and never assume something is fine until testing proves it.

HolidayCoro.com

Where Do I Start When Designing a New RGB Pixel Project for My Holiday Display? (Updated for 2026)

Updated September 2026. We rewrote this guide to reflect how pixel displays are designed and built today, including the software most of our customers now use.

HolidayCoro receives a lot of questions each year from people who don't know exactly where to start with the design of a pixel element (house outline, MegaTree, arches and so on), and we understand how overwhelming it can be when you're just starting out. After working with so many customers, a fairly standard process has emerged that takes most people from "How do I?" to "I did it!"

Want help with your project? Fill out our project design form and we'll put together a recommendation and a complete quote with the lights, controller, mounting and accessories you'll need.

Here is the overall process. Each step is covered in more detail below.

(Click the picture to enlarge)

Common questions before you start

I don't want to solder.
You may not have to. Many of our pixels come with waterproof plug-in connectors on each end, and our Ready2Run packages arrive assembled. Elements like MegaTrees can be almost entirely plug-and-play. A house outline is always custom because every house is different, so expect some cutting and connecting there. If you do need to solder, we have videos on the subject, and it's easier than most people expect.

What is a pixel?
A pixel is a single light, or a small group of lights, that can be set to any color independently of the lights around it, much like a pixel on your computer screen. What a pixel is NOT is a whole string of lights that all change to the same color at the same time, even if those lights are RGB. Every pixel is "smart." There is no such thing as a "dumb pixel."

What about dumb RGB?
Dumb RGB is now rarely used. The cost of pixels has come down so much, and pixels can do so much more than dumb RGB, that there's little reason to choose it for a new project. If you aren't using dumb RGB today, stick with pixel products. See our post on dumb vs. smart RGB for more.

What voltage should I use?
The two common pixel voltages are 5v and 12v DC. For most holiday projects, 12v is the more forgiving choice because it runs longer before you need to inject power. See our Knowledge Base article on the pros and cons of each.

What pixel controller do I need?
People often worry about this early, and it's usually one of the easier decisions. We like to say you don't pick the controller, the controller picks you. Once you've defined your design, pixel count and power, the choices narrow quickly. Our Controller Selection Wizard walks you through it.

I don't know anything about DMX. Is this going to be hard?
No. Pixel controllers receive their data over your home network using a protocol called E1.31 (also called sACN), which is DMX sent over Ethernet. There are really only two things to know: a DMX universe holds 512 channels, which is 170 pixels at 3 channels each (red, green, blue), and each controller output is assigned a starting universe and channel. Your sequencing software handles the rest.

Can I connect pixel controllers to my old Light-O-Rama controllers?
Not directly. Older LOR controllers use the LOR protocol over RS-485 serial cable, which is now considered legacy technology. All modern pixel controllers, including ours, use Ethernet. To connect multiple E1.31 controllers, you just use an ordinary network switch.

Step 1: Pick a single project

It's easy to watch YouTube videos of amazing pixel displays and wonder how to get there. It starts with narrowing your focus to a single project, or "element." Think about the whole display, but build one element at a time. Controllers, power and mounting are usually specific to each element, so building one at a time gets you a win and makes every project after it easier.

The most common starting points are:

House outline

• The house becomes the frame for your whole display
• Always custom, since every house is different
• Mounted with Pixel Pipe (seasonal) or PixaTrack (permanent)
• See our house outline primer and detailed design guide

Pixel MegaTree

• Makes a huge impact in a display
• Can be close to plug-and-play when bought as a package, including pre-sequenced songs
• The mounting system is usually the hardest part, not the lights or controller
• See our MegaTree packages and the MegaTree Builder Wizard

Pixel arches

• Typically very easy to build, often in a few hours
• See our arch packages and arch building accessories

Pixel props

• Stars, snowflakes, singing faces, candy canes and hundreds of other shapes, pre-drilled for pixels
• Standard shapes make purchased sequences much easier to use
• See our pixel props

Step 2: Determine the design

Once you've picked an element, decide exactly what you want it to look like. Some questions to ask:

House outline

• Which areas will you outline: roofline, gutter/fascia, windows, doors, garage?
• Can your audience actually see each of those areas from the street?
• Do you want it up for the season, or year-round?
• Do you want the look of nodes, or of traditional bulbs?

MegaTree

• Where will it go: against the house, on a corner by itself, in the middle of the yard?
• How tall should it be? Will it overwhelm the rest of the display?

Arches

• How many, how long, and how tall?

Without a clear idea of the design, it's nearly impossible to work out the rest. It's also hard to know the cost until you've been through the whole process, so you may need to go through it once, then scale the project up or down to fit your budget.

Step 3: Determine the light type

There are several physical formats of pixels. The major groups are:

Nodes
Nodes came from the sign industry in Asia, where channel letter signs are made from sheet metal drilled with 12mm holes and filled with these lights. The holiday lighting community adopted them, and today 12mm nodes are the most common pixel for house outlines, MegaTrees and props. They come in bullet and flat (square) styles, both with a "neck" that fits a ~12mm hole.

Bullet style node. Note the neck that fits a 12mm hole.

Flat or square style node.

Strip (ribbon)
Pixel strip is a flexible circuit board with LEDs along its length, sold by the meter. It's described by LEDs per meter and pixels (ICs) per meter, so 30/10 strip has 30 LEDs and 10 pixels per meter, with every 3 LEDs acting as one pixel. Strip spacing is fixed and it needs a substrate to mount to, so today it's used less for outlines and trees than nodes, but it still has its place. See our pixel strip.

Modules
Squares, rectangles and pucks with LEDs mounted in a rigid housing. Useful where pixels need to point in many directions or fill an area. See our pixel modules.

Bulbs
Pixels with a diffused cover that mimic the look of traditional C7 or C9 bulbs, like our Brilliant Bulbs. A great choice if you want a classic look with full pixel control.

Not sure which you like? Our Pixel Light Selection Wizard can help.

Step 4: Determine the mounting location and method

Nearly every pixel needs to be mounted to something. Pixels are more fragile than traditional lights, and they need to be accurately spaced and aimed because each one has a specific location in your sequencing software. If the lights don't match the layout, the effects won't look right.

Start with your audience. If your display is viewed from the road, stand in the road and look at it from a typical viewer's height. Avoid placing elements where they block each other (a MegaTree in front of a house outline, for example). A good rule of thumb is larger items toward the back and smaller items toward the front.

House outline

• Make sure every outlined section can be seen from where your audience stands.
• For a seasonal install, Pixel Pipe holds your nodes at a fixed spacing and snaps into clear clips that can stay up year-round.
• For a permanent install, PixaTrack encloses the wiring and comes in off-white or brown to blend with the house.
• Mounting under the fascia or soffit hides the hardware but can reflect light onto the wall ("wall washing"). Mounting on the front of the fascia gives a crisp outline.

MegaTree

• Most trees only need to look good from the front (about 180 degrees), since they usually sit at the back of a display.
• A MegaTree is really a rectangle of pixels wrapped into a cone, so the pixels need consistent vertical and horizontal spacing. PixNode strips and the QuickTree mounting system are built for this.

Arches

• Arches are simple: a bent pipe, the pixels attached along it, and stakes in the ground. See our arch building accessories.

Think through the whole life cycle: not just building it, but installing it, repairing it and storing it in the off-season.

Step 5: Determine how many lights you need

More pixels isn't always better. Think about your TV: stand two feet away and you can see the individual pixels, but from across the room the picture is smooth. Holiday pixels work the same way. What matters is the spacing of the pixels compared to how far away your audience is.

Pixel type	Recommended viewing distance
12mm node, 1" center-to-center	10 to 50 feet
12mm node, 2" center-to-center	20 to 80 feet
12mm node, 3" center-to-center	60 to 120 feet
60/20 strip	10 to 60 feet
30/10 strip	30 to 170 feet

Why not just add more pixels?

• Past a certain distance, no one can see the difference. Tightly spaced pixels on a house viewed from 150 feet away look the same as wider spacing.
• More pixels means more channels. Every pixel adds three channels, which means more controller outputs, more network data and larger sequences.
• More pixels means more power. That means heavier wire, more power injection and bigger power supplies.
• Colors blend at a distance. Alternate red and green on very tightly spaced pixels, view them from 75 feet, and you'll see a muddy yellow instead of crisp red and green.

Pick a spacing that fits your viewing distance. Nodes and bulbs let you choose your spacing; strip spacing is fixed.

Step 6: Calculate power and pixel counts

Now put on your math hat. Pixel count is the length of each run divided by the spacing:

20 feet × 12 = 240 inches ÷ 3 inch spacing = 80 pixels

When planning spacing, check three limits with your vendor:

• Minimum spacing, the closest two pixels can be mounted.
• Maximum spacing, set by the wire length between pixels. Confirm the center-to-center spacing, not just the wire length.
• Maximum gap, the distance the data signal can travel between pixels or from the controller to the first pixel. If you need to go farther, long-range receivers or "null" pixels can bridge the gap.

Then calculate power. Watts = volts × amps, and 1 amp = 1,000 milliamps (mA). For example, our 12v 12mm nodes draw about 45 mA each at full white, or about 0.55 watts. A 100-node string is about 55 watts. Add up all your pixels, then size your power supplies with headroom above the total.

Published specs are a starting point, but the only sure way to know is to measure. Wire gauge, temperature, supply voltage and the quality of the pixels all change the real number. Set your pixels to full white for 15 to 30 minutes and measure with a meter.

For a fully worked example, see our detailed house outline design guide.

Step 7: Select the controller

With your pixel counts and power worked out, choosing a controller is straightforward. Look at:

• Pixels per output. How many pixels each output can drive.
• Power per output and per controller. Don't go by the fuse rating; the fuse protects against shorts, it doesn't define capacity.
• Number of outputs. One per continuous run, plus room to grow.
• Distance. A central controller works when your runs start close together. For larger layouts, a controller with long-range receivers lets you put outputs right where the runs start.

No matter how powerful the power supply is, there's a limit to how much current can travel down the small wires in a pixel string. Past that point, you bring power in partway down the run. This is called power injection:

Our Controller Selection Wizard walks you through the options, or browse our Ready2Run pixel controllers.

Step 8: Select the sequencing software

This used to be a hard choice. Today it's easy: use xLights.

About 80% of our residential customers sequence with xLights. It's free, it runs on Windows, Mac and Linux, and it has the largest community and the most tutorials of any sequencing software. At this point, xLights is better than the paid alternatives in every way that matters for a pixel display: its effects are built for pixels, its visualizer shows your display on a model of your house, and it can map sequences built for someone else's layout onto yours.

To run the show itself, most people pair xLights with FPP (Falcon Player), free show-player software that runs on a small, inexpensive computer like a Raspberry Pi. You sequence on your PC, copy the show to FPP, and it runs your schedule every night without tying up a computer.

About 15% of our customers use Light-O-Rama S5 or S6, usually because they already own LOR hardware and sequences. All of our pixel controllers work with it over E1.31. If you're starting fresh, though, start with xLights.

Step 9: Choose how you'll get sequences

There are two approaches, and many people use both:

Sequence it yourself

• Every sequence is 100% customized to your display.
• No sequences to buy.
• It takes time: anywhere from an hour per song for a simple sequence to many hours per minute of music for a detailed, hand-built one.

Buy pre-made sequences

• Lets you use sequences built by people with more experience.
• Works best when your elements match the sequence: MegaTrees and standard props like ours are the easiest.
• Custom elements, especially house outlines, will need some remapping. xLights makes this much easier than it used to be.
• See our MegaTree sequences and whole house pixel sequences.

Let us help

We've tried to boil the process down to its essentials, but it can still feel like a lot. Start with a single project, and like nearly all of our customers, you'll be building bigger and better elements before you know it.

If you'd like a hand, fill out our project design form and we'll put together a recommendation and a complete quote for your project.

Have a great season from HolidayCoro.com!

How to Solder Waterproof Wiring to Pixel Strings (Video)

Worried about how to solder your waterproof extension cables to your pixel strings?  Worry no more, the following video shows how simple it is to solder on wiring to your pixels:

The following products were used in this video:

10ft, 3 core extension cable
12v, WS2811 Pixel String
1/8" Heat Shrink Tubing
3/8" Heat Shrink Tubing

New Customer Projects

We have customers that do some amazing projects with our products - sometimes they are Holiday related and sometimes they go a completely different way.  Here are a few projects our customers have sent in to us this year:

Steven G's Christmas Boat Parade:

Darin D's Pixel Party:

Chris H's Custom Produced Salvation Army Signs:

Valentino D's Dance Party with Singing Monsters:

Soldering Extension Wire onto Strip Light

We have customers that are sometimes concerned about working with strip lighting we sell and how they can extend it and/or attach connectors to it.  The video below shows how simple and quick it can be to solder on extension wiring onto strip lighting:

You can find our extension wire here:

4 Conductor, 18 AWG
3 Conductor, 18 AWG

Is a RGB Pixel Package A Good Choice for My RGB Project?

A very common question we get is - does HolidayCoro have a package or kit of RGB pixel items that can be used for RGB projects.  This blog post hopes to be able to provide you with sound advice about when a "package" or kit is a good choice and when it isn't a good choice for you and your project.  This article is a follow-up to our "Cheap Isn't Free When It Comes To RGB" blog post which talks about the pros and cons of DIY vs vendor developed solutions from a time and cost perspective.  First, let's start off with defining the project you plan to build - while there are many different types of projects that involve RGB and/or pixels - in this article we will use the two most popular uses of pixels today and the ones for which we receive the most questions about:

• Outline a House (soffit, fascia, roof line, windows, etc) with pixels (covered in this blog post)
• Building a pixel MegaTree

Outlining A House with Pixels

Each time we work with a customer on a house outline there are many common items/questions for all installations - length (linear feet) of area to cover, density of control (pixels per meter or inch), budget, controllers and the overall look the customer wants to achieve.  Let's start with these and look at the different options:

• Length of area to cover - There is never a single length for any house type because each house has different lengths and each customer wishes to outline different areas (windows or no windows, roof line or no roof line).  As such, any "package" deal would need to have the specific amount of lighting for that specific installation.  Additionally, other factors such as long run lengths that might need 12v lights instead of 5v lights can also factor into the decision based on the design of the house.
• Density of control - Some displays are viewed from hundreds of feet away, others are viewed from tens of feet - as such, the value of specific pixel density (30 LED/m vs., say 48 LED/m or 60 LED/m) changes from display to display.  Additionally, with different density comes different sequencing and bandwidth requirements, which, depending on the display, can be an important factor.
• Budget - Each person's budget is different and that factors into how they design their display.  Some customers will want nice moulded waterproof connections on lights, others are satisfied by basic, non-waterproof connections.
• Controllers - The number and type of controllers will vary depending on the physical layout of the house.  Sometimes it can be be cheaper and easier to install more controllers than less due to the amount of additional wiring that would be required to support just one controller.

As you can see, even with just this small subset of factors that go into the proper design of a house outline - there will never be the same "package" for each house because there are just too many variables involved.

For house outlines, you'll either need to use a guide like our, how-to blog post on the subject to design your own or use a design service offered by some vendors that look at your specific needs and then can recommend the exact right combination of hardware for your house.  Currently no other vendor other than HolidayCoro offers custom house outline services.  As HolidayCoro attempts to strike a balance as we are a low-margin hardware vendor we offer design services as an additional for fee service which can be found here:  https://www.holidaycoro.com/Services-Consulting-s/1858.htm

For a representation of the hardware in a common house outline, see:  https://www.holidaycoro.com/RGB-House-Outline-Packages-s/1967.htm 

Pixel MegaTree

A pixel MegaTree is a very common project for many displays.  A pixel MegaTree is pretty much just a large matrix of pixels, wrapped around a cone and is used to display effects.  There are a number of inputs into a MegaTree and they are:

• Height and Width of the MegaTree - Typically a "package" MegaTree will be set for a specific height because the diameter of the tree along with the spacing of the pixels in the package determine the final overall height.  If the size of the tree and the mounting method used to build that tree work well for you, a package may be a good choice.  If you have specific spacing requirements, such as the high density needed to display readable, scrolling text, the pixels included with a package may not be the best choice.  Additionally, if you have specific needs such as a smaller tree due to a small yard or close proximity to your audience, or, if your display is huge and you need something more in "scale" with your other display items, a packaged design likely isn't a good choice.
• Pixel Type - The type of pixel used on a MegaTree greatly affects the overall look and functionality of the MegaTree.  Choices can include nodes, strip or even bulbs.  Each physical type of pixel has a pro and con.
• Controller / Power - Since MegaTrees are typically full (360 degree) or half (180 degree) cones, it makes sense to have the power and controller centrally located in the trunk and thus most packages include a controller, power supply(s) and mounting box.

So, while a MegaTree does allow for some level of "standardization" to allow for it to be put into a package, make sure that package meets your pixel type and density requirements - if your specific needs, such as height, spacing or node type differ, you'll likely be better off with a custom solution instead of a package.

HolidayCoro offers common pixel tree formats of 50 pixels x 12 or 50 pixels by 16 in strips and nodes:  https://www.holidaycoro.com/RGB-Pixel-Mega-Tree-Packages-s/1964.htm

If your needs are more specific, HolidayCoro can also design a MegaTree based on your specific project requirements through our consulting service: https://www.holidaycoro.com/Services-Consulting-s/1858.htm

Portable Storage Cases Review (video)

For readers of this blog, you likely find that building your display requires storage of lots of little parts - items like zip ties, SPT plugs, fuses, replacement bulbs, solder, small tools and more.  Keeping all those items separated but together in an easy to use and portable form is important when you go to build your display. Or maybe you just need to organize the garage and get a handle on all those little nuts and bolts so you can finally find them quickly.  The following video review covers seven different cases by four different vendors and aims to narrow down which of these cases are the best value for the job at hand.

Here are links to the products listed in the video:

• Sortimo T-Boxx (corporate site)
• Stack-On DCOG-10
• Stack-On DO-17
• Stanley 014725
• Stanley 014026R
• Harbor Freight Item #93928
• Harbor Freight Item #93927