What is a Lynx Smart String?

[tbone321]

Ok that is an idea to use more hubs to be able to spread things out. But then won't it cost more because each hub will need a water tite box as well as my time to build each hub? And making  up extension cords or even buying them premade in different lengths for the smart strings would be easer maybe.

The reason for the use of multiple hubs are to not have numbers of cables running all over your yard and more importantly to use much less expensive power suplies.  If you push the hub for all it's worth, the demand for power will be quite high and require a large power supply.  You need to remember that in the smartstring world, it is the hub that supplies the power for the smart strings.  The more pixels or nodes that you have a hub controlling, the more demand for power they put on it.  400 and 500 watt power supplies are fairly inexpensive at around $50 but 800 and 1000 watt ones can exceed $150 easily and then you have the second issue of it failing shutting down a large pat of your show. 

[richardb]

I've not read between the lines and calculated this... But I have tried finding it and can't.
What wattage power supply is recommended for a fully loaded hub?

[rm357]

Power requirements document is on the wiki
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Short answer 16 strings x 128 nodes = 61.56 amp or 738.72 watts on the 12 volt rail. You will need a ~900 watt or greater power supply to get that as the total rating includes the 3.3, 5, -5, and -12 volt power rails.

Be careful to look at the 12v output as you are evaluating power supplies. Most of the cheap (<$20) ones only have around 15 amps @ 12 volts. With the hubs expected to cost in the $50 range, it might make sense to really load one up - $50 hub + $100 power supply vs 2x$50 hubs + 2x$50 power supplies

Also, be sure to look for power supplies with a single 12 volt rail. It is never a good idea to connect the outputs of two power supplies together, the same applies to two power rails in the same supply. Depending on the design, you may be OK, but since you are not privy to that information, it is safer to just not do it. The issue is that if the two outputs are not perfectly matched (or protected), the supply with the lower voltage will work to regulate down the higher voltage supply - sure it may be only a 0.1 volt difference, but with the very low output impedance of a power supply, that can be many amps...

RM

[richardb]

Cool. Thanks.
I see the wiki has been updated significantly since my last visit...

[boarder3]

So if i use a 50 amp service for my lights now going by what i see i need a 61 amp service just for one hub. Is that correct?

[matt_grooms]

One thing that you have to take into account is how many channels you intend to program.  Remember that each pixel uses 3 channels so a single 128 node string will use 256 channels.

Math was a little off  ... 128 node is 384 chs or a couple more with the Hybrid mode for the phantom channels.

LOL, thank you. That's what I get for answering it at 3:00AM.

Multiply that by 16 and you get 4096 fun channels to program.

Actually my understanding is the 4096 limit is from the current Lynx Dongle's limitations in the throughput of the PixelNet with the modified firmware.  The future Pixelnet dongle will send out 16K channels.

The 4096 limit is a full pixelnet universe.  The current dongle limit is that it can only output 1 universe.  The new dongle when it become available will use all 4 pairs to output 4 universes which will give you to the 12000 channels that you are thinking of but even here if I understood RJ correctly, each hub can only work with one universe so the limits on the hub minus the math errors are still valid.

That is my understanding up to this point from what I have read from RJ.  I know he will step in if this is incorrect, but hope that helps.


-JS

Whoops, I think I just woke up.

So the current dongle (4096 addresses) can't control a fully populated hub with maximum  length smart strings attached (128 nodes * 16 strings * 3 channels per node = 6144 addresses).

Understand that the future pixelnet dongle will support way more but for now we're (obviously) limited to 4096 addresses per hub. So one could attach a maximum of 10 fully populated smart strings (128*3*10=3840 addresses), OR attach 16 partially populated (85 node) smart strings (85*3916=4080 addresses) .

So for now a single hub populated with 128 node smart strings cannot perform in 100% independant node RGB mode.
Never mind that the programming of this many individual nodes is impractical, and that hybrid mode allows controlling 16 fully populated smart strings on one hub coonnected to the current dongle.


This isn't a negative comment, just wanted other folks who may have been dozing (like me) to be aware of the technical limitation (until the new dongle is released).

[rrowan]

I guess that is why so many people are ordering lots of dongle pcbs

Rick R.

[RJ]

Yes we have said this many times but maybe it is not getting through to people.

128 is not some "I got to have 128 nodes or it ain't %#*&" 128 nodes is an insane string almost 40 feet long!

This is just limit not the norm folks. A 20 ft megatree will use somewhere around a 70 maybe 80 node string. So since you can run all 16 at 85 nodes this means this would be a common size.

The power requirements to go 16 128 node strings makes the power supply cost much more also.

I am not sure, maybe it is just our mentalilty of excess that make everyone want to run the longest string they can.

RJ

[rrowan]

I am not sure, maybe it is just our mentalilty of excess that make everyone want to run the longest string they can.

RJ

But But DAD,

I only plan to run 52 to 60 nodes on 5 SSC

Honest!!!!

Rick R.

[tbone321]

So if i use a 50 amp service for my lights now going by what i see i need a 61 amp service just for one hub. Is that correct?

LOL, not at all.  The 50A service that you are using is based on 120V.  The 61A that the hub would be using in your example is based on 12V which is about 6A at 120V.  If you look at the specs on either the ATX or fixed 12V supply that you decide to use to power the hub and strings, you will see the input current which is the demand being placed on your 50A service.

[tbone321]

Whoops, I think I just woke up.

So the current dongle (4096 addresses) can't control a fully populated hub with maximum  length smart strings attached (128 nodes * 16 strings * 3 channels per node = 6144 addresses).

The current dongle puts out a full pixelnet universe so no dongle would be able to control a fully populated hub with full lenght strings configured in pixel mode because there simply isn't enough channels in a pixelnet universe to do it.

So for now a single hub populated with 128 node smart strings cannot perform in 100% independant node RGB mode.
Never mind that the programming of this many individual nodes is impractical, and that hybrid mode allows controlling 16 fully populated smart strings on one hub coonnected to the current dongle.

It is not for now, it is forever.  Even hybrid mode would probably not work because the string controller would not be able to be configured at such a high starting address and a number of nodes that would put it beyond the 4096 channel limit of pixelnet.  
  

This isn't a negative comment, just wanted other folks who may have been dozing (like me) to be aware of the technical limitation (until the new dongle is released).

This is not a limit until the new dongle is released.  It is the limit of pixelnet and even the new dongle will not change that.  

[RJ]

Before we successfully confuse everyone,

  Each hub can only use one universe of PixelNet. This means a hub is limited to 4096 channels. But you can use many hubs and each can have the same or one of the 4 different universes.

There is only one universe per standard current model dongle.

But the later generation PixelNet dongle will provide all 4 universe at the same time on the same cable. so the limit on one dongle will be 16384 channel and it should be possible to use more than one of them to get you to more if you are really wanting pain (seqencing) later one.

RJ

[gophergrove]

Can I add some more confusion RJ? 
You mentioned once or twice there will be other hubs (smaller and passive) coming down the pike, do you have any more info on them to share?

[RJ]

Not at this time.

RJ

[matt_grooms]

RJ / tbone -

Thanks for the further clarification on the address-per-pixelnet_universe-reality vice the pixelnet_universe-per-dongle-reality vice the 1-pixelnet_universe-per-hub-reality.

Let myself slip into thinking a hub could could use more than one pixelnet universe's address range if only the new hub was available. "dumb. dumb."

Sorry if I stirred a pot that didn't need stirring.