RGB as simple as 1, 2, 3
The eight pixel house
There’s a technology heading for the decorative lighting world that has the potential to be a very disruptive force. Just as we try to get our heads around basic LEDs to displace incandescents, now we’re being asked to use something called RGB based lighting, meaning the lights can be told to change to any color of the rainbow. Good gosh. Can someone slow down so the rest of us normal people can catch up?
LEDs are here to stay
By now you probably already know the advantages of Light Emitting Diodes (LEDs). They only consume 10-20% of the power of their incandescent cousins, have a lifespan 20-50 times longer and can be manufactured to emit light in almost any color. LEDs are solid state devices so they are incredibly durable and you seldom have to worry about breaking one when accidentally stepping on it.
LED based Christmas lights are finally getting reliable, bright enough and in many cases, have a physical form factor just like their incandescent cousins so old-timers feel comfortable using them. Now the complaint is some LED based holiday lights are too bright when used indoors and need a dimmer so they can fit in with the mood of the room.
Most LED based light strings work fine in a computer animated environment, indoors or out. Deploying large displays is easier since you don’t need to spend near as much time and money focused on the electrical infrastructure required to supply huge amounts of power. Many find it’s cheaper to totally replace their incandescent lights with LEDs than having to put in new electrical distribution panels to handle more incandescents.
A real LED benefit is the bulb color doesn’t fade over time. A string of blue LEDs remains the same color year after year because the light is created internally as blue instead of in incandescents where a white light is colored by a blue lens that fades in the sunlight. LEDs produce very pure and vivid light colors.
Can you tell LEDs are the future of holiday lighting decorating? They are. As your incandescent lights wear out, it makes sense to migrate to the LED world. LEDs might initially cost more but we’ve found they are a good investment.
Now there’s something called RGB LEDs. Someone figured out you can project the colors red, green and blue (RGB) at the same place on a screen and the resulting color is white. They call it the additive color model. Mix the red, green and blue intensities and you can create almost any color. Put red, green and blue LEDs close together, back away, mix the intensities of each color and the human eye sees all the different colors of the rainbow. Merge those three discrete LEDs into something that looks like a single LED and now you have an RGB based LED. One point of light can be commanded to be almost any color. This is the basic concept behind the computer screen you’re probably reading these words on right now. RGB technology is what drives the full color animated signs you see at businesses and the latest generation billboards along the highway.
Here’s where things can get overwhelming
With a typical string of Christmas lights, power is provided over two wires. The light string is wired in such a way as to distribute the power as needed to all the bulbs. Adjust the voltage level and all the lights dim or brighten equally. Remove the power and they go dark. It’s easy to understand because the electrical circuit requires only one control channel, no matter how many lights are on it.
With an RGB based LED, you must supply it with three different power feeds: one for red, another for green and still another for blue. The voltage level of each power feed determines the final color we see coming from the RGB light source.
An RGB based LED can be wired to be controlled individually or in such a way where several RGB based LEDs are controlled as one. The industry calls each of these RGB based groups a pixel. Your high definition television has over two million very small RGB pixels. The key for decorators to remember is an RGB pixel can be one or several RGB points of light.
If you’re familiar with Light-O-Rama’s pioneering Cosmic Color Ribbons, you’ve experienced RGB based LED technology. A Cosmic Color Ribbon is five meters long and has 150 RGB based LEDs mounted on it. The long ribbon can be configured so it has 50 pixels, meaning the ribbon is broken into 50 sections and each section is three RGB LEDs. Each section of that ribbon is under your full control and can be any color at any time. With a little programming a computer can make those individual sections chase each other, change colors and wow your audience. That’s the good news.
The not-so-good news is programming those RGB LED pixels to create all the light acrobatics we’ve become used to seeing can be daunting. Each pixel requires three control channels: one for red, one for green and another for blue. One pixel isn’t bad. 50 pixels? 150 control channels. Have a thousand RGB LED pixels? Now we’re talking 3,000 control channels and users start talking about channel explosion. If you’re challenged by programming a simple 16 channel light controller then RGB based LED displays have the potential of thousands of channels, intense frustration and a need for hardcore computer geeks.
If you really want to get into programming/sequencing/using RGB technology with hundreds or thousands of pixels, there are some decent options. Light-O-Rama has an add-on to their standard sequencing software called SuperStar. Colored start and end points are created on a virtual lighting grid and the software figures out how to build and transition the pixels over the timeframe you select in the music. Another option is a program called Madrix and has been profiled in PlanetChristmas magazine in the past. This is a standalone program that listens to the music and creates its own pixel designs in real-time. SuperStar and Madrix are powerful but can be tough to master. There’s also the challenge of connecting the output of the programs to all of your RGB LEDs. Typically, the raw RGB communications protocol is based on DMX-512. Remember the need for that hardcore computer geek before? Now you need an electrical engineer that’s also a computer geek.
Dip the toe
What can you do if you want to dip your toe in the RGB LED waters without worrying something nasty will bite it off? Consider single pixel (aka: dumb) RGB devices and direct RGB control.
What’s a single pixel RGB device? A good example is an RGB based floodlight. It’s one physical device but has three control channels. That floodlight can be commanded to produce any color by mixing the output of the very bright RGB LEDs built into it. We found some great floodlights at Light-O-Rama and are rated at 10 watts each, meaning they’re bright and can hurt your eyes if you stare into one. Most RGB devices work at 12 volts DC so a 10 watt RGB flood requires about one amp of power. Some floodlights we have found are also waterproof meaning they can be submerged in a fountain. How much money are we talking about? Less than $30 a floodlight.
Now take a look at one pixel RGB ribbons. The light ribbon is five meters long (a little over 16 feet) and all the LEDs can be told to be the same color simultaneously by mixing the proper RGB control channels. You can easily outline windows, doors, stairs, railings and eves. Depending on the type of ribbon you have, we’ve found the current draw to be around 1-2 amps. Some of these ribbons are even designed for underwater usage. How much? Less than $50 a light ribbon.
How do you control these single pixel RGB devices? Light-O-Rama has introduced a special 24 channel low voltage controller designed specifically to work with eight RGB devices. It’s the CMB24D. How much? $110.
We started dreaming about what could be done in the holiday lighting world with this single pixel technology. Management gave us permission to find out on a real house.
Build an 8 Pixel RGB System
We ordered a Light-O-Rama CMB24D controller and started experimenting. The board requires a low voltage power supply and we quickly “re-purposed” one from a retired laptop computer. The RGB controller board has eight output connectors with each connector pin labeled +, R, G, B. Each single pixel RGB device has four wires labeled +, R, G, B. Matching the connector pins to the wires couldn’t be easier and required only a small screwdriver to secure. Within minutes we were making our single pixel floods and ribbons change colors through the Light-O-Rama Hardware Utility test console.
We started thinking about how to really test single pixels and soon the crew was outside attaching RGB light ribbons to a structure. Here’s how we did it and what we learned.
Single pixel devices on a real house
I wish we I could say we went searching for the perfect house to use as our test bed. Nope. We used one of our own and planning consisted of a poor drawing on a napkin. We did think ahead just a little and knew we needed to use the Light-O-Rama design concept of four groups of four so we could use their off-the-shelf sequences. In our minds we ended up with four horizontal elements (the windows) and four vertical elements (the gutter, door and steps.) We attacked our project at around 2:30 that afternoon.
We found an outdoor enclosure that used to hide the timer for an irrigation system and it was perfect for mounting our RGB controller board and power supply. Someone did have to rummage around to locate a 12 volt DC supply big enough to power the electronics on the controller board as well as the RGB devices we attached to it. Since we knew each RGB single pixel device could draw up to two amps of power and we were using eight of them, a 20 amp power supply made sense. We had a supply purchased earlier from eBay for about $25 and it proved perfect for our needs. With a little effort you can find 5-20 amp outdoor related DC power supplies specifically designed for LED use at a reasonable price. Be careful of using the power supply from landscape lighting systems because many have an AC output.
We played with the RGB floods but ended up not using them in our real-life demonstration. The structure was brown brick and didn’t reflect light well so we stuck with the light ribbons.
It didn’t take us long to figure out light ribbons are great for straight lines. Right angle turns and curves aren’t what they’re designed for. Depending on the type of ribbon being used it can be sliced at designated cut points to create a 90 degree turn but you need some single conductor wires to bridge the cut segments. Slicing and soldering is easy but does require a steady hand and you can’t overheat the ribbon. We found slicing and soldering provides the cleanest look but it’s a hassle in the field. We ended up applying some clear silicone caulk to the cut ribbon ends to keep the connections weather
If you have some extra length to your single pixel ribbon you can do a “loop, twist and turn” at the 90 degree corners. It doesn’t produce the cleanest change of direction but you don’t have to do any cutting and soldering, either.
Some ribbons come with double-sided tape on the back. Peel off the protective paper and stick the ribbon on a smooth surface. It’s very convenient as long as you’re careful and it’s always 70 degrees. The crew found when outside the double-sided tape heats up, lets loose and the ribbons tend to fall off the structure. We ended up using some extra wide staples to physically attach the ribbon to the structure at key points. Be very carefully to not puncture the ribbons with the staples, for obvious reasons. The ribbon proved very flexible and easy to work with, at least during the summer. Use common sense in colder weather and bend the ribbons with care.
The house had stairs leading to the front porch and the crew was getting tired. They ended up just laying a couple of ribbons on the stairs to create a clean horizontal line. Much to everyone’s surprise, they looked great.
When the crew was done mounting the single pixel light ribbons to the structure late that afternoon, they stepped back about 25 feet to admire their work. The casual observer would never notice the light ribbons.
The crew started speculating about year-round displays. Leave the lights up and use different color schemes based on the season. Orange for Halloween, red/green/white for Christmas, pink for Valentines and green for St. Patrick’s Day. The possibilities become endless.
Distributing the power
Each single pixel RGB device requires four wires. One common and a control wire for red, green and blue. Even though in our experiments each single pixel device drew 2 amps or less at 12 volts, we were concerned about voltage loss over long distances. Earlier we had managed to score some four conductor, 18 gauge alarm wire on eBay and it proved ideal for running from our centrally located RGB controller to all the RGB devices. We experienced no voltage drop issues. The key to remember is voltage drop is your enemy and the wire can never be too big.
We did discover why the RGB ribbons are only five meters long. Some ribbons have the option of extending the length by simply plugging another ribbon into the end of the first. When the entire ribbon was fully powered everything looked fine a few feet into the second ribbon and then all the LEDs started to fade. We figured the copper traces used in the light ribbons were not thick/wide enough to handle the extra current required by the second ribbon. We found it best to power each RGB single pixel device individually. We used two single pixel ribbons along the eve of the structure, ran a separate 4 conductor cable to each but connected both ribbons to the same RGB pixel connector on the controller board.
Making the RGB devices dance to the music
Since there are only eight RGB devices/pixels in our setup, it’s pretty easy to sequence the lights to music. Remember, each RGB pixel requires three channels so with the eight pixels we needed 24 channel sequences. In our case we purchased an off-the-shelf ‘You Can Modify’ 48 channel sequence from http://sequences.lightorama.com and remapped the first 24 channels to the 24 RGB channels using that four by four design concept. It took almost five minutes.
The crew waited until dark, plugged in our RGB controller, fired up the sequence on the computer, turned up the music on the speakers and stepped outside. We were dazzled. With just a few hours of work the house was dancing to the music with ribbons of lights so much brighter than typical Christmas lights outlining a window. Watching the light ribbons change colors in perfect sync with the music was quite a rush.
The lights weren’t on for more than 30 seconds before cars were stopping and people asking how we did it. Some commented on the crisp, straight lines of the lights. Others talked about the intense colors. The rest were just mesmerized with all the pretty colors flashing to the music.
According to the timeclock, about four hours ahd been invested in this little project. The crew deemed their work a success. Since then not a day goes by where someone around the office doesn’t talk about how they’re going to ‘RGB’ their house this Christmas. Then they start talking about Halloween, 4th of July and it never really ends.
RGB based LED technology definitely can have a place in the holiday decorating world. The key is don’t be tempted or intimidated thinking you need thousands of individually controlled pixels of light. A few single pixel devices changing colors at your command can make a big difference in any display. Remember to start small, grasp the concepts and hang on for all the fun you’re going to have amazing your audiences.
This article was included in the September 2013 issue of PlanetChristmas Magazine.
By the PlanetChristmas Elves