Pixels 101
How It Works

So you want to learn about pixels and what makes them blink and flash? Perhaps you saw some display or performance and often wondered.... hmm how did they do that? So you searched high and low and realized your up and over your head in information.  Its almost like you want to take a sip but instead they hand you the fire hose!  The internet is rich of information but as many new to this hobby find you will find a plethora of information.  So... You are here because there is some itch to understand more, but with one issue on your mind??? How and where do I start?  I hope to provide you with the needed information so you can begin and enjoy your new found hobby.  Please note this blog post is in the works and there will be grammar errors. As time progresses I will get this cleaned up and updated. 

THE BEGINING Of LIGHT SHOWS- Blinky flashy lights have been around for quite awhile.  You see them everywhere  from the street signs of main street to the Electronics you have in your house. One thing is for sure if you want to stand out with lights you need to make them BLINK! Back in day if someone wanted to have a light show display they used AC lights with a mechanical relay wheel that would turn on sections of lights in a timed sequence and repeat over and over again. It was a kind of effect or blink that would animate light to life.  Over time mechanical wheels were replaced by transistors and later by integrated circuits. Lights themselves have evolved from the traditional incandescent bulb to the now popular LED.  

LED's LED's and more LED's   Light Emitting Diodes or LED's for short are used in todays lighting trends.  Sure they are not new but their use and increasing popularity have pushed manufactures to improve and release new kinds even as we speak!  LED's are passive meaning they too function simply kind of like a light bulb.. Something has to turn it on.  LED's are everywhere and their power consumption compared to their predecessor is much lower making them much more desirable.   One thing to note...LED's in the electronic world are driven a bit differently then a traditional light bulb.  LED's typically use DC (directional current).  If you are somewhat familiar with electronics you will know that LED's are also diodes.  A diode is an interesting but very important electronic component. LED's because of their diode nature will only allow DC electricity to flow one direction.  If you connect them backwards to power they will not light up.    Not only do LED's commonly run on DC current they also prefer to be ran by a pulsing method. The Pulse method  is commonly known in the electronics world as Pulse Width Modulation or PWM... Say What?????   That's alright. Occasionally you will hear terms here that are going to be confusing, but hang tight we will try to explain.   PWM is a fancy way of turning  the LED on and off rapidly, and it does this so fast that the naked eye can't tell the difference.   What the eye can't see is that PWM can actually shorten and lengthen the LED on and off state so rapidly that it appears the LED is either really dim or super bright.   Why do they do this??? Well its to help drive the LED more efficiently. For the most part here you don't have to worry about LED voltages and current too much yet.  We will however explain the types of LED's that are used and what common voltages they require. 

PIXELS,  RBG LED's, Smart LED's  What's the difference?  So before we throw the phrase pixel at you lets got back to the LED.  In the LED world you have many colors.  You options are to buy fixed colors or you can buy and LED that can mix and combine colors to give you a multitude of colors. That's where RGB comes into play.  RED, GREEN or BLUE or RGB.   We won't go into primary colors and  how they mix at the moment but most here understand that Red, Green and Blue can be mixed to give you many other colors.  Just a side note if you mix all three at full intensity you get White..  So an RGB LED is a single LED with multiple LED's inside of it.  It has 4 pins.  In order for a LED to light its needs a specific voltage current to run.  On a single RGB LED you have 4 pins.  One for Power and the other for each color.  We wont get into complexity here but some may be asking which is positive?  Well that depends on the RGB LED. It could be 3 negatives one for each color and one positive or the RGB LED can have 3 positives and one negative.  Ok besides the point you most likely wont go down this rabbit hole right away.  Just know that RGB LED is an LED that has three primary colors in a single space.   What's a smart LED?   Well lets take the RGB LED and put it on a microchip that can control each color with the PWM method we discussed previously.  What does that buy us?  Well now this is where the term PIXEL comes into play.  A pixel is a smart RGB LED that can be controlled to display any color you want based on what PWM intensities are currently programmed into the chip.  In fact Smart Pixels have evolved to have the chip built right inside them!!  you can barely even pick out the small microchip dot, yet that dot has some intelligence and the ability to be controlled!  OH now your asking for it. to be controlled.... stay tuned!!!

SMART LED's CONTROLLED.  Now that you are down this rabbit hole you need to be ready.  For what we are going to mention here may need some pause time and may even need to be re-read a few times.  That's ok.  I wasn't born smart, neither am I smart.  I just keep doing things over and over until it sinks in.  Pixels are smart devices that require a controller to tell them what to do.  As a pixel sits, when you power it up it usually does nothing.  Absolutely nothing.  You may be lucky and it will glitch out a color, but what you will quickly find is it will do nothing until you tell it to. Pixels have one more awesome feature and that they actually connect with other pixels. Now wait lets back up.  Not only does a smart RGB or Pixel change colors but it also allows you to program it and it will send additional programing to the next pixel in line. In the electronics word we call this shifting or shift registers.  Lets use the bucket brigade analogy.  If you want to get water from one side to the next and you have a dozen people you scoop up the water with a bucket and hand it to the next guy.  That guy hands it to the next, so on and so on.  So what happens in that analogy?  Water gets from one side to the end. Lets take that concept to pixels.  If  want to tell my dozen pixels to display colors I need to pass all data to the first and let it pass it on to the next until its complete.  So each pixel is intelligent to pass this data to the next and so on until its done.  Now this is where it gets interesting.  Pixels have a method to know when to start the process over again.  We call this a reset and there are a couple ways we do this but we won't cover this detail or method at the moment.  

Pixel Controllers  So how do we control pixels?  Well with a pixel controller.   Pixel controllers come in all shapes and sizes and prices.  They are designed to take information from various sources and shift out the color information to the pixels that are connected to it.  Pixel controllers can have multiple outputs allowing many pixels to be connected.  Pixels do have limitations.  One is that you can only have so many pixels connected in a row.  Why?  Well lets take that bucket brigade analogy.  If you have thousands of bucket brigade-ers (is that a word?) how long is it going to take to get your water to the the end?  Well most here would agree a long while.  Pixels are no different.  The more you have connected in line the longer its going to take to send the data to each one.  The longer it takes to tell the pixels what to do the less time I have to show pixels.. Right?.   In the TV and movie world you may be familiar with Frames per second.  On a movie you typically will be given at least 25 picture frames per second.  The end result is a fluid video that you can't really tell they were still pictures to begin with.  Pixels Controllers and pixel are much the same.  The controller can send data to the pixels at a very fast rate to where we as humans can't tell.  The shorter the pixel strings the faster we can "frame".  Pixels that frame faster then 25 frames per second will look more natural to the human eye and you will see less stuttering.  So keep this in mind and know that pixel controllers have multiple outputs to allow high pixel counts.  Guys who do shows with pixels will usually have thousands of pixels.  When you look behind the scenes they will run several hundred pixels and then stop, but then right after that last pixel they will begin with another set connected to another output from the controller.  From the front of the show we don't see that pixels stop and start again with a new strand... all we see is a bunch of pixels that appear to be all connected together when in reality its several sections connected to individual outputs on the controller made to look like one continuous string...  .  TO BE CONTINUED!!