Another Noobie in need of advice

http://www.aliexpress.com/item/100pcs-DC12V-12mm-WS2811-led-smart-pixel-node-with-all-color-wire-20AWG-IP68-rated/1932882946.html
Ami doing the math correct?
1x20m =200smart nodes(3ch)@120w=600ch ?

Every pixel is three channels. They are controlled electronically and you don't need to run a separate wire back to the controller for each channel.

Those are typically sold in sets of 100 nodes so two sets of 100 nodes is 600 channels (correct).

Don't trust the current/wattage values given on the AliExpress listing. They are typically higher than you'll actually measure.

Every pixel type/voltage has its disadvantages too. I want to make sure you know that the disadvantage of 12V strings is that they are inefficient power users and not quite as bright as 5V strings. It is easy to run strips and strings together if you decide you want to; they can even share a controller output if they are compatible types.
If you order 12V pixel strings, you should specifically ask Ray to make sure they draw 30mA per pixel (10mA per colour). See this thread for an example where the 12V strings drew too much current http://auschristmaslighting.com/forums/index.php?topic=7420.0

When it comes to controllers, you have many options. I would suggest spending extra and getting an out-of-the-box type for you so you don't have to solder. If you're good with technology and your soldering improves, you can save a lot of money by buying a BeagleBone Black, PixelBone and using Falcon Player with 2811 and/or 2812 pixels.

The Australian suppliers of ready-made pixel controllers include BensChristmasLights http://clap-supplies.com/
and Advatek (L_Tay and Devo) www.advateklights.com

There is also the F16v2 controller which may be hard to get hold of but it's certainly excellent value and will control just over 10,000 pixels (over 30,000 channels) if your display grows that big.

If you get a pixel controller with a DMX512 output, you will be able to plug your LOR controllers into it with a crossover cable and control them via E1.31 along with your pixels.


Do you understand how E1.31/pixel channels are divided into universes? This is general knowledge that helps when choosing a controller, setting up the display in your sequencing software and when configuring a controller.

David_AVD created a nice set of calculators on his site and 1 that may benefit you is http://www.da-share.com/calculators/led-strip-string-current/ . It also calculates pixel nodes. 1 thing to be aware of is the 12V nodes draw the same current as 5V nodes but use 2.4 times the power.
The simple method I use to overcalculate the required current is to work out the each colour of a pixel draws 20mA which equates to 60mA per pixel. Multiply that by the number of pixels and that will give you the current required. That can then be multiplied by the pixel voltage (either 5V or 12V) to give the power. This method will give you a very quick estimate of the current and power and leave some safety headroom as most pixels are about 18.5mA per colour (55mA/pixel) and when in circuit it's usual that you will end up with an average of less than this.

AAH have you measured that consistently occurring over a wide range of 12V pixel nodes? I was sure that the 12V ones normally only drew 10mA per colour although I don't own any. The thread I linked to was an exception. The 10mA per colour is the reason they're not quite as bright and it is also partly the reason why you can have longer runs of pixels without needing power injection.

There is no standard for the actual pixel current. The 2811 has a maximum current of 18.5mA/channel. I think 2801 can do 20mA. From manufacturer to manufacturer the current that they have chosen will vary. Believing the specs on Aliexpress is a good way to get burnt.

Ok I thought I had seen how universes worked but now have no idea where can you point me in the right direction

A universe can be thought of as a group of data sent to your pixel controllers. Each universe contains enough data for 170 pixels (you can still use a universe for less than 170 pixels). The number of universes per controller output can therefore be used to calculate the maximum number of pixels per output. You will need to number your universes in your software and controller setups.

Remember that you usually need power injection to use the total number of pixel universes that the controller supports.

There is another point worth considering; while convenient for long pixel runs, if a controller supports a large number of pixels per output, one blown pixel can take out a larger number of others with it until you fix the problem.

DMX512 outputs increase the controller's total number of universes but don't control pixels. You're never going to need more than one DMX512 output.

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