Intermediate pixel guide
Welcome to the more intermediate guide on how pixels work.
If you haven't read the beginners guide please do so here is the link to that guide.
- 1 A quick overview of sequencing
- 2 Which RGB is right for me?
- 3 Whats up with these Protocols?
- 4 Now lets see how all this new found knowledge applies to the controller boards themselves.
- 5 Ok so I know what pixels what protocol and what controllers I am interested in now what?
- 6 Bringing it all together- the link to the next wiki and other readings
A quick overview of sequencing
If you have been looking around the forums, at other sites, or talking to anyone who has computer controlled lights. You have heard the term sequencing, if you haven't heard it yet, you will. What is this sequencing and how does it apply to me your asking. Sequencing is what is done on your computer, this is the software that generates the signals turning on or off the lights. It sounds really difficult but in reality most of the work of the software is done in the background with you not seeing it. There are a lot of different sequencing software out there, the DIY community does have several that we use and share with each other. There is also some software that is commercially available. All the software does the same thing, generates the signals to run the controller boards. The software interface on the screen shows like a spreadsheet with time across the top left to right, and your channels down the left side starting at 1 on the top. When you assign a song to the sequence most of the sequencers will display the song in wave form at the top so you can visually see areas that have higher volumes (this can help you in getting the lights to start and stop when that volume happens). You then have the fun (yes this really is fun not joking) of putting in the effects you want (these can include fades (called ramps), steady on, twinkle or a myriad of other effects) and at what time you want the effect to start and stop. Most sequencers have a preview screen, this is just a screen that has a picture (of your house I hope) with a layer over it that has the locations of where each channel is, see your individual software to set up the preview correctly. As you assign effects you can view them using the preview watching the lights turn on and off in time to the music. If you don't like where an effect is you can adjust it and then preview again to make sure your show is exactly how you want it to be.
NOTE Sequencing is the thing that takes the most amount of time to do, start early. Depending on how many channels you have sequencing can take upwards of 2 hours for just 30 seconds of song so a show with 3-5 songs lasting 6-10 minutes could take several days to sequence.
Which RGB is right for me?
In the first guide, pixels vs traditional lighting, the differences was covered, this should aid you in selecting a RGB light profile. This will now expand on some of the rest mentioned in that section.
Dumb RGB vs RGB Pixels and how this applies to your show.
Dumb RGB as you know only take up 3 channels per strip/string so sequencing them is much easier, the major factor in going for these is the cost vs future needs. While the dumb RGB stings, no matter the profile, are less expensive. Adding several of these may require several controller boards to get the color pattern your looking for. Their savings on the strings may be offset or even make them more expensive than going with RGB pixels due to the number of controllers. Dumb RGB controller boards typically control around 8-32 strings (24-96 channels). Dumb RGB were the first RGB strings introduced, and generally are being replaced by the RGB pixel. If you decide on the dumb RGB strings you will know why you chose these.
RGB Pixels take up a lot of channels depending on how many pixels you use, making sequencing a lot more challenging (their are tools built into most sequencing software to help deal with the vast number of channels used in smart pixels). RGB pixels can be controlled like a dumb RGB string in that we can individually turn several pixels in a row the same color. If at some point in the future you are going to want to change from dumb RGB to RGB pixels on a prop, eave, or window outline, due to the effects that RGB pixels allow, the suggestion is to get the RGB pixels and control them like dumb RGB. To change from dumb RGB to RGB pixels at a later time means repurchasing the strings and the controller boards. Right now RGB pixel strings are about 10-30% higher in cost, the controller boards are about 50% more expensive, but as was stated above you may have far less controllers. RGB Pixel boards range from a single universe (512 channels) to 64+ universe (32,000+ channels). When choosing RGB pixels you understand the higher possible initial cost will allow the effects your wanting either now or in the future.
5 volt vs 12 volt what this really means.
In the electricity world wattage is everything, its how you are billed every month typically in kilowatt hour. This sounds like a big number but its really not. A watt of power is voltage times the amperage (current). Amperage is increased as resistance is decreased. In lighting when you decrease the resistance you increase the brightness (a result of more amperage flowing through), a 100 watt bulb is far brighter than a 40 watt bulb, the input voltage is still either 110 volts or 220 volts household voltage but the 100 watt has lower resistance so it glows brighter that's the difference between them, The 100 watt bulb uses up that 1000 watts in 10 hours, the 40 watt bulb would take 25 hours to use 1 kwh (kilowatt hour). Where to use 12v vs 5v: as electricity travels down a wire the wire has a small amount of resistance in it, the bigger around the wire the less resistance is felt (I know, not what you were thinking there right?). As voltage encounters resistance (both from the wire and the lamps themselves) a portion of it is consumed lowering the voltage available further down the wire. Since a pixel runs on about 3.3 volts (a built in resistor drops the input voltage to the 3.3 volts needed), a 5 volt input there is very little wiggle room for that voltage drop before the voltage is no longer be able to correctly power the lamps. In a 12 volt string we have a lot more wiggle room so longer runs are possible with the 12 volt input. We can hook strings of RGB together (both dumb and pixels) but at some point the voltage is too low to properly power the lamps. To overcome this we can reintroduce the 5 volt or 12 volt (a reset button of the voltage so to say) at a point or points in longer runs, this is referred to as power injection. As you can see resistance plays a role in both amperage and voltage affecting the number of watts used in anything electrical. If you peeked at the wiring smart pixels wiki you saw at the beginning a general rule of thumb, power inject 5 volt every 50 lamps, and on 12 volt every 100 lamps. Depending on how long you want the strings to be will better help you determine what voltage is right for you.
Whats up with these Protocols?
As stated in the beginners wiki there is a bunch of different protocols, mostly determining the right protocol for you depends on how "big" your show is or is going to get, and how future proof you want to be. At first we have only a "few" channels ranging from 16 for traditional lighting to a couple thousand for doing all smart pixels, all these channels need to be refreshed or resent out several times a second to keep the lights doing what you want them to do. Each protocol has so much data it can send out each second (baud rate) some of the original protocols used are around the speeds of early modems 16000 bits per second. These are wonderful for traditional lighting, since the protocol has been around a longer time its costs are generally low, pixels on the other hand have the need for several thousand or even several million bits to go out each refresh, so those early protocols are far too slow for pixels. The rate of refreshes determines how often the lights can change states (dim, brighten, or in pixels change colors). They eye can generally pick up anything slower than 23 times per second (think of flicker on a TV set) Most TV's refresh their picture 29-60 times per second. In computer controlled lighting you also want to maintain at least a 25 refresh per second rate or your effects will look to jump from element to element instead of flowing from element to element. We talk in electronics mostly in milliseconds (1000 milliseconds = 1 second) so 25 refreshes per second works out to about 40 milliseconds between them, if were sending that several thousand bites of data every 40 milliseconds we need several hundred thousand baud rates to keep up. Enter the newer and faster protocols, these can range from several hundred thousand to over one hundred million bits of data every second.
This will try to talk about the protocols in terms of speed from slowest to fastest and their pros and cons. Note: there are other protocols not listed here that generally are not used in the DIY community and will not be covered by this wiki.
Serial RS232 - This is the oldest and slowest protocol, it is not used in pixels due to its baud rate limitations. Though it can be used in traditional lighting systems as it is very inexpensive for equipment.
Serial RS485 - This is the first usable protocol by pixels, serial data is put out either by the serial ports on the back of your computer (some modern computers have eliminated one or both of these so your computer may or may not have these) or on the USB (universal SERIAL bus) we need a piece of equipment to convert the serial data to RS485 protocol, typically these are either a plug in adapter using the serial ports on the back of your computer or a "dongle" on a unused USB port. Both of these function the same converting serial data to the RS485 protocol. RS485 is a standard that supports up to 32 drivers and 32 receivers on a single computer output. Its data rate can vary from 100kb/s to 10mb/s making it very flexible for use in large pixel displays. You will find that a lot of the commercial controllers use this (light o rama uses this protocol almost exclusively).
E1.31/ACN - This is refered to as DMX over ethernet. This is a suite of protocols that is most commonly used to control theatrical lighting, audio and effects. ACN can be combined and configured with other standard protocols. It can be implemented on a variety of networks, typically using Ethernet (E1.31). This is a form of carrying data, but not the final form, meaning we need a bridge to have the DMX512 sent to the boards. Its rates can vary from 256kb/s to 100mb/s. This uses the same protocol as your internet connection on your computer. E1.31/ACN data is not recommended to be broadcast on your home wired or wireless network as the amount of data going through it will interrupt or bring your internet to a crawl. Instead we typically use a private network to run this protocol. Because this uses Ethernet, a knowledge of ip addressing as well as mac addresses is needed to configure this, making this a little more difficult for a new person to grasp right away (unless your the I.T. guy). This being the newest protocol its availability is lower and costs are higher than using older technology. This can support over 63,000 universes making it a very future proof way to go.
Now that we have the protocols done lets look at what their carrying:
Renard The Renard data set, created by Phil Short (originator of the Renard controller concept and firmware) is quite a robust, solid and easy-to-use communication setup. However, like most things, there are some limitations to making it work properly. Renard primarily uses "serial" protocol like RS232 or RS485, so its data rates are limited to those baud rates.
DMX512 DMX is a standard that describes a method of digital data transmission between computers and lighting equipment and accessories. It is the language for many solid state lighting boards. This is used by by professional lighting. We borrow this technology to use in our systems. Typically DMX is transmitted over ethernet (e1.31) or can be sent locally from board to board. (local transmission is usually 1 universe worth of channels)
In summary here you have computer to output (either serial or Ethernet) to bridge (either a dongle on the usb for serial, or bridge for e1.31/acn) to board. Important controller boards are not universal, the protocol and controller board must match.
Note in some high density smart pixel boards the bridge is built into the board allowing direct connection to e1.31 networks.
Now lets see how all this new found knowledge applies to the controller boards themselves.
Renard - These boards are truly DIY. These boards are designed at the circuit board level by members on these forums. They are usually sold as kits that come as a circuit board and all the things you will need to solder onto it. If you are not able to or do not want to solder these are not the boards for you. These boards are tweaked to give the "best bang for the buck" though when it comes to controller boards. There is plenty of support for these boards so don't shy away from them because their "hands on", besides there is a special pride in watching someone stare starry eyed at your show knowing that it was built by you (not just assembled by you) As far as RGB renard does have the ability to have dc ssr's for controlling dumb RGB, it also has the PX1, a RGB pixel controller. Keep in mind this still uses the RS485 serial transmissions and at 230k baud rate (the highest recommended for the px1) it is limited to about 400 pixels per serial adapter. The px1 is a great board for getting your feet wet doing RGB pixels if you already have an existing renard system.
DMX - These boards accept direct dmx input. Typically they have dip switches to select where inside the dmx universe their start channel is. These boards require some sort of bridge to change the transmitting protocol into dmx. All these boards are small single universe boards.
E1.31/ACN - These boards can be broken down into several groups. These boards directly accept e1.31 input no bridge is needed. These boards range in size from single universe to 16 universe and even higher. Here I will try to break them down a little
Central controller - These are the grand daddy boards, their ability to handle massive channel counts make them a true power house. Boards here would include SanDevices E68x, Alphapix 16, Falconv2 16, and other 12+ universe controllers. The biggest draw back here to these boards is the way that pixels in and of themselves work. The data line is subject to noise making long runs of wire with no pixels in it limited. These are best suited where you have a huge cluster of pixels (mega trees) where their high channel counts are needed.
Auxiliary controller - These are still very channel heavy boards, handleing between 7-12 universes each. These are smaller boards where you have a cluster of decent density (rooflines with house outlines and windows) The boards included here would include the SanDevices e6804, alphapix 4, and other 7-12 universe boards. These boards typically have higher counts on individual outputs than the central boards, though they typically have only 4 outputs.
Stand alone controller - For lack of better name, these are where you have a light pixel concentration that is 2-7 universes. There really isn't many boards out there in this range, mostly if your needing something in this size it will be things like arduino boards with modified sketches and such to give you what you want. While these boards are inexpensive there is generally not a lot of support for them. Most people opt for aux boards and the extra channels/outputs just ignored or looked at for future expansion.
Single Universe wireless here in the last few years these have become very popular, its very easy to use a wireless one universe controller somewhere and put pixels just about anywhere in your yard/house. Here there is several solutions, Komby wireless, these are based on the nordic nrf and use ardunio processors, unlike the stand alone these are greatly supported by komby and others on the forums. Another option sporatic has espixelsticks, these use wifi to get their data. Once again great support on these. The nice thing about the single universe stuff is the receivers are generally small just an inch or two by 3/4 of an inch boards... they can be tucked away and will let you have that corner where there is nothing suddenly has a universe or two of pixels.
Note There is a list of vendors in the forums these are individuals who are active in the DIY community and some have assembled boards for a great price (not as inexpensive as you doing the soldering, but not near the cost of other commercial products). We here in the DIY community try to support each other not only with knowledge but with our dollars as well (buying from other DIY members)
Ok so I know what pixels what protocol and what controllers I am interested in now what?
Now that we have the idea of what were getting its time to look at how much we are getting. SET A BUDGET that is realistic knowing you will always run over.
For info on what you need before you buy your first pixels or boards the forum under Main Category, How do I get started, has several sticky threads that list some items that you can start stocking now. Some of them you may already have others are things you may not have thought of. There also is a sticky on drawing your design out and figuring out what you need to buy as far as strings, extension cords, cables, ect. If you find that your design is over your budget scale it back you don't need 10 arches, 8 mini trees, the eaves, and the mega tree your first year. To be exact i would discourage anyone from doing that much even if their budget allowed it. All that has to be built, trouble shot (not everything is going to work the first time you plug it in), and on top of doing that you need to sequence everything!!!! Start small maybe the eaves this year, next year add a few things. Nothing brings people back to see the show more than every year having something new.
Now you have the "necessities" from the forum (did you remember zip ties?) and a pretty good idea of what you can afford/realistically sequence, you also have a decent knowledge of what is needed as far as controllers, pixels, and such. Its time to:hit the forums!!!?! (wait were not buying stuff yet?) A good place to start is to ask if you have everything correct by posting, in the correct forum (renard stuff in the renard sections), your diagram including controllers, pixels, bridges, and power outlets. While these wiki's gave you a general knowledge the individuals here can help you to refine your diagrams add stuff you didn't think of or something not covered in these wiki's. NOTE you will receive a lot of different ways to accomplish what your wanting, if someone suggests something your unfamiliar with then ask them for clarification or "google" it and see if that may be a way for you to go, there is no right way to control your show its up to you to decide on the final design.
Note do not use pictures you see on sites to say if a string/strip is rgb dumb or rgb pixel, some sites are very misleading in their pictures showing a strip/string being multiple colors at one time (the illusion of pixel control) while the actual product is a dumb string/strip. Always look for the pixel designation (ws2811 for example) to ensure your getting a pixel and not a dumb string/strip. When ordering pixels at first try to stick to 3 wire pixels (ws2811, ws2812b) these are very popular and for the most part the least expensive of the pixels. If ordering strips you should see the strip saying +12v/+5v on one pad, di/do for another pad (data in/data out) and gnd for the 3rd pad. If you are seeing +12v/+5v r,g,b these are dumb strips and are NOT pixels no matter what the description or pictures show.
Once you have the final design then start ordering stuff (remember some of this stuff may need soldering, may be coming from overseas, or may just be out of stock and you may need to wait before receiving the items or using them). After you have the items begin testing them then assembling them (this is where the zip ties come in) after you have everything assembled and tested that its working correctly, run a few sequences that you have made on them, fine tune your sequences to the actual lights now instead of the preview (there may be a slight delay in the real stuff that wasn't in the preview) after you have everything done, you then can set it up outside when it gets closer to your show start date (weather may play a big part of how soon stuff actually goes up), remember just because it worked in the basement doesn't mean it will work outside you may have to trouble shoot some stuff after set up outside (allow yourself plenty of time is what this is basically saying, well and plenty of zip ties too)
After that sit back and watch people oooogle at your handiwork and bask in the glow of the twinkling lights.
- Advanced Pixel guide - This is a link to the next wiki in this series
Other wiki pages that expand on what was discussed here