RGB pixels and decorative lighting
We all remember the time when we saw the light display that got us hooked. 35 years ago my parents took their eight year old to a nearby suburb where nearly all the houses were decorated with lights. The display that grabbed my attention had its lights being electronically coordinated and controlled. To the best of my memory it was only about eight channels of lighting control, but back in the late 1970s this was virtually unseen and I was amazed at the patterns that could be created. It burnt a memory in my mind that still stays with me to this day.
Now I create memories for those that come to enjoy my decorative lighting display, with channel counts that have substantially grown. There have been a lot of changes in lighting and the technology that drives our lights. Most of these changes occurred in the past ten years and the complexity of our displays continues to grow. Having been involved in the electrical industry for the last 25 years and a founding members of www.auschristmaslighting.com, which specializes in teaching all about decorative RGB lighting for the Do-It-Yourself enthusiast, I have acquired the knowledge and skills required to design complex decorative light displays. Now I can demonstrate an easy way to use new colorful, pixel lighting technology for the general lighting decorator. Let’s take a quick look at the past, then work our way to the present and into the future, discussing the intricacies of pixel lighting technology.
Advances in Decorative Lighting
Decorative lighting has come a long way in the last ten years and even more in the past two to three years. We have seen major shifts in technology, from using the standard incandescent string, to controlling lights with AC dimmer controllers. This led to the LED (Light Emitting Diode) revolution. Today we are entrenched in the RGB light and pixels revolution. Many people are curious, “What is RGB, and what are pixels?” RGB describes a red, a green and a blue (RGB) LED contained within a single embodiment, allowing color-blending between the three. This enables us to use virtually any shade of any color in our displays.
Simple RGB is commonly referred to as dumb RGB or single pixel RGB, meaning that the whole light string or
strip is controlled as one. Pixels are an extension of RGB lighting and incorporate a miniature IC (Integrated Circuit chip) into every light or small group of lights, which controls one LED independently of other LEDs. This is commonly referred to as intelligent lighting or pixels.
Controlling lights with a computer to create custom patterns began many years ago. The actual date of this is hard to determine as it was well before the Internet. Early adopters used automated, Programmable Logic Controllers (PLCs) to control their lights creating patterns. Then a small community of Christmas lighting enthusiasts developed their own controller boards. They began with just an on-and-off control, but software was developed to allow easier sequencing and control of the lighting. Additionally, music was synchronized with the light display. This was revolutionary, ushering in the beginning of synchronized musical Christmas light shows. Controllers were developed with the ability to dim the lights’ intensity. Different controllers started becoming available as this online community grew.
During this evolution in lighting control, the LED was born. The LED was far more efficient and reliable. Initially LEDs could not be reliably dimmed, until a company called Minleon introduced the first dimmable LED replacement bulb to the U.S. market. LED lighting was revolutionary because the technology allowed users to have many more lights without running into power load concerns. LEDs consume eight to ten times less power than traditional incandescent lights. Plus, LEDs do not require the level of ongoing maintenance that average incandescent strings require. But many people thought LEDs color wasn’t appealing — especially the whites — and avoided them. Now with certain states like California having bans on incandescent lighting due to their high
level of energy waste, we will see a continued phasing out of incandescent lighting over the next couple of years.
Recent improvements in LED technology have given us a much better color selection with many types of white color options now available.
Because of their ability to blend colors, RGB LED lighting is becoming more common. If we want red only the red LED shines. If we want purple then both the red and the blue LED shine. If the red, green and blue are all turned on, we will get white. By dimming any of the combinations of red, green and blue we can create virtually any color in the spectrum. This is commonly referred to as being “dumb” or single pixel RGB lighting control. Effectively we now have three times the channels of lighting to control compared to what was previously available with the single-color, traditional light string. In the past many users needed three or four separate light strings to achieve what one RGB light string could achieve.
The latest evolution in lighting technology is pixel control, also known as intelligent or smart lighting. With pixel control, a small integrated electronic circuit chip is added to each LED or a small group of LEDs, so lights can be turned off-and-on, dimmed, and changed color independent to the other lights in a string. This lighting primarily started in the digital signage industry, but hobbyists quickly recognized the potential of using these lights for decorative purposes. Pixel-controlled lighting dramatically increased the possibilities in sequencing RGB LED lights. A string of 50 lights has gone from one channel for single-color string, to three channels for a three color string, to now 150 channels for the same amount of lights for an RGB pixel string. This is a substantial increase in the way we manage our lighting and in the intricacies with which we sequence large channel displays.
Solutions to Pixel Data & Power Limitations
With elaborate light displays data distribution and voltage considerations must be taken into account. In the past, when using 110-volt light strings and dimmers, this was not an issue. Pixels use a form of data that is sent through the light string. The first light in the string receives the data for the whole string. That IC chip grabs the first 3 channels of data (red, green and blue) to process before passing the remaining data onto the next light until the last light in the sequence receives its data. The data effectively is cascading down the string. Each IC chip for each light thinks it’s the first light and grabs the first 3 channels of data before removing those 3 channels of data and sending it to the next light/IC chip.
Pixelated data has a limited distance range. In most cases the distance between the first pixel and controller, or between pixels, should be eight to 20 feet with the shorter the distance the better. The lights tend to flicker and become uncontrollable if the distance between the controller and the first pixel is too far. This issue is solved in two ways.
The first method is to use a ‘dummy pixel’. Each pixel’s IC chip in a string regenerates the data signal before sending the data to the next light/IC chip, so by adding a ‘dummy pixel’ we can effectively increase our distance between the first pixel and the controller or increase the gap between lights.
A second method is to use a differential data signal. A small piece of hardware converts the pixel data to a more stable transmission that can travel a greater distance (300 feet) from the controller to the first light, or between lights. By the end, this data is then converted back to the original data signal that was originally sent from the controller so that the pixel IC chips can process.
Solutions for Voltage Drop
When using low voltage, pixelated lighting we need to be aware of voltage drop. Pixels normally run on 5vdc or 12vdc power. This low voltage has inherent issues that need to be managed. Voltage drop symptoms usually are seen when mixing all three colors to get white—when the maximum load is channelled down the wire. All three colors are running at 100%. Signs of voltage drop can be noticed in a pink tinge in the lights that progressively gets redder down the string as the level of voltage becomes lower. Another symptom is flickering lights, as the IC chip struggles to maintain control due to the voltage drop created.
You may wonder, “Why use low voltage and not 110-volt like with traditional strings?” The reason is LED circuit design. LEDs have a voltage rating specification of approximately 3.2 volts for green, 3.2 for blue and 2.3 volts for red. When LEDs are joined together in a series circuit (connected one through the other) we add the voltage of each LED that is in the series circuit together. So for a 110-volt circuit using a green LED you may see approximately 30 LEDs connected together in a circuit. This raises the LED circuit to approximately 96 volts (30 x 3.2 volts) and in turn creates a much more efficient LED circuit when running at 110 volts. We still have to remove 14 volts from the supply to maintain the desired 96 volts to run our LED circuit. The issue here is that the fewer LEDs used in this circuit, the more inefficient this design becomes. Running a single pixel that has an LED with a rating of 3.2 volts on 110 volts is extremely inefficient as nearly all the power will be wasted as heat. For this reason, pixels cannot run on 110 volts as they are either an individual LED or a small group of LEDs (three to six LEDs). This is why LEDs mainly come with either 5vdc or 12vdc ratings. But by using 5vdc or 12vdc we must deal with voltage drop.
Voltage drop is the percentage of volts that is lost across the length of a wire or string. Voltage drop is a combination of four main factors which are the fundamentals of electricity known as Ohm’s Law.
- Current (I) – Amps are the amount of energy flowing down the string based on the amount of lights connected and running.
- Resistance (R) – The smaller the gauge of a wire the higher resistance to the flow of electricity. The longer the distance of wire the higher the total resistance.
- Voltage (V) – The higher the voltage, the lower the current becomes and thus the lower the percentage of voltage drop. The lower the voltage, the higher the current becomes for the same watts of power used.
- Power (P) – Power is measured in watts and made up of volts and current. For example, a 300 watt power supply at 5vdc will output approximately 60 amps (300/5), but that exact same 300 watts of power running at 110 volts will then only be drawing approximately 2.73 amps (300/110) for the same amount of power used. So as the volts go down the current goes up for the same amount of power needed.
Through manipulating these factors—by using larger sized wire (resistance), having shorter distances between the power supply and the controller (resistance), using 12vdc instead of 5vdc (voltage) or under-driving the LEDs to use less power (current)—you can manage the level of voltage drop that is seen.
With 12vdc power and a single LED you still are wasting more power than you are using for actual light. So the user must compromise. The LEDs normally are driven by the IC chip to run at a lower current level, this affects light output. To the average human eye this can be hard to detect as we do not see light in a linear fashion. Light becomes saturated at the higher ends of LED power and dimming, so by reducing the current, we reduce the wattage and thus reduce the amount of wasted energy with very little noticeable visual difference. What we see in some light strips are two or three LEDs connected in series so that the voltage needed is closer to the 12vdc and thus less wasted energy.
5vdc power is a more efficient method when running pixels because the voltage difference needed to run the LED is lower. But using 5vdc means higher current requirements, with the percentage of voltage drop being a lot less compared to that of a 12vdc system. Using 5-volt requires larger gauge wire to carry the extra current.
The interface used to connect your light controllers from the computer also has changed with the onset of pixel technology. In the past, light controllers were connected via the USB port to a computer, but the USB port has data transmission limitations. So many larger channel pixel controllers now work on a computer Ethernet network. The two main protocol standards used are Art-Net and E1.31. These are made up of channel universes. Each universe is 512 channels, but for pixels this is actually 510 channels because three does not divide equally into 512. This equates to 170 RGB channels or pixel lights per universe (510/3). You can see how the traditional USB dongle quickly can become uneconomical with larger pixel driven shows. Alternatively, a computer Ethernet network will allow for tens of thousands of channels through the one network interface. This is a present trend.
An alternative and simple approach is to have a standalone light system where the sequence is stored on an SD memory card through a master controller. This takes away the need to use a computer to run your light show.
The final challenge to be aware of when dealing with RGB pixels is sequencing. We have gone from a single channel string to a string where each light is now three channels. This has dramatically increased the channel counts and the hardware requirements needed for RGB pixel lighting. We need to use software that allows for easy management of RGB pixels. Where in the past a single light display element was made of three or four independently controlled strings or electrical channels today may have thousands of channels. Each of those channels/lights must be mapped into the sequencing software. Traditionally sequencing was done in a grid with a time line and timing intervals. Then effects were placed onto a particular channel(s) within the grid using timing intervals. This was not hard to manage when we designed light shows with 256 channels or less. But as the channel count increases, the channels and display elements become harder to manage the traditional way. Software developers now use a more object-based sequencing approach. Instead of sequencing the appropriate channels with a controller, we now see an approach where we create the display elements, sequence at a display element level and apply effects to that display element. This means a controller can be made up of multiple display elements or a display element could be made up of multiple controllers. You can then group these display elements within your display together to then treat your whole display as one element. This approach allows for greater control and simplicity.
Different sequencing software exists with varying levels of RGB pixel support and complexity. It is recommended that people play around with the different offerings within the community to find the software that suits them best. There is no piece of software that has it all, but there are some that have a lot more to offer than others.
A Little About Minleon
How can you include this effective lighting technology in your displays without having to manage power, data and sequencing? Light shows inherently need to be managed, but Minleon is working on solutions for the novice market. Minleon is a lighting company who made their name in the U.S. with high-quality dimmable replaceable LED bulbs. They now offer an extensive range of RGB pixel lighting products and control systems which are made with the highest quality. Many commercial installers swear by their products due to the quality material and proven track record of reliability. Minleon is focused on developing RGB lighting with the novice in mind. They produce a wide range of controllers, lights and accessories to make it easier for both entry-level displays and full blown commercial light shows by offering a comprehensive range of products and accessories that will suit beginners and professionals alike. Minleon has taken a scalable approach with their product offerings. New users can operate their simple single-output controllers straight out of the box. They are installed with built-in effects operated by remote control. The same lights and controllers connect to a computer and Minleon’s Lightshow Pro software for direct control if and when a user desires to delve more deeply into light design and take full control of how their show functions..
Minleon already offers standalone show capability with their Effects Controller system. A user can sequence with Minleon’s LightShow Pro software and export the custom sequence file to an SD card for standalone playback. To make things even simpler, a user can avoid pixel sequencing and SD cards if he chooses, as the Effects Controller has over 20 built-in effects that can be adjusted to suit any event as you need it.
More options come with the Effects Controller standalone system—which also offers built-in effects, and the Network Controller which has the option of using industry standard protocol like Art-Net. Both novices and professionals can use this technology with confidence.
Looking to the future, Minleon has recognized that control through mobile phone apps is a simple way to make RGB pixel lighting more accessible to use. Minleon will release a wireless controller through a mobile phone to allow the user to play back a song in their phone and have the lights dance to the music in real time. The user also will be able to choose any color or effect they desire, remotely or even play games with their lights. You will be able to use your lights for Christmas, but also for any occasion: parties, garden lighting, whatever your imagination can dream. The next step in the evolution of decorative lighting is here and now: making pixel lighting much simpler and hands-on for everybody. Stay tuned for the next evolution. Looking for more information? www.minleonusa.com
Who is Fasteddy? I’m an Electrical strategist for Australia’s largest steel making plant which means that I deal with maintenance planning, maintenance manual creation, root cause analysis, and improving the production value of the electrical assets. I’ve been involved in the Christmas Lighting hobby for a while and was one of the founding members of www.auschristmaslighting.com, which I’m still very active on, so I’ve enjoyed doing this and still do at a hobby level and have been doing RGB displays for many years. I have been looking to turn my hobby into a business and Minleon is a good company. So now I’m working on making that happen in my little part of the world downunder, also known as Australia.
This article was included in the April 2014 issue of PlanetChristmas Magazine.
By Edward Vassallo (aka: Fasteddy)