Powering pixels

The single greatest thing that is going to affect the ability to get 3m,5m,10m or whatever is power. If you have a nice reliable 5V or 12V both at the last pixel between a gap and at the first pixel after the gap you should have very little problem going to 10m.
Doing actual tests including snapshots of the waveforms with my oscilloscope is on my "to do" list as many people are under the misconception that data rate rather than power is the way to get longer distances.
 
Last year running the WS2811 strip I was able to get away with 6m on some strip and not quite 6m on others without adding a null pixel. Using the test pattern from the controllers made everything look ok at 6m but when testing them in an actual show sequence, I found some strip would get stuck part way through the sequence and that problem was only cured by shortening the distance below 6m. Having said that, I wasn't power injecting these strips so I can't comment as to whether things may have improved with extra power.
But from experience I would agree with the earlier posts stating that what looks fine in a test may not equate to a smooth run when running an actual musical sequence.
 
Alan, when you say power do you mean the voltage through the data cable (is it voltage that goes down the data cable?) or the V+ cable. I have 12v coming from the controller at the upstream end of the cable and 12V injected into the strip at the downstream end of the cable. Different power supplies so the v+ is not linked.

If it is the voltage of the data cable you are talking about can I just use my multimeter on the data and grnd wires to test voltage at each end.

Having said all that. I told a little fib about the test I did last night. During the test I had 6m of ink1003 (2 by 3m lengths joined together) on the downstream end of 10m of 14/0.2 cable and the whole thing was actually powered through the controller and it all worked on the test pattern including white. I am planning on powering the strip at the start of the strip in my show. That is why I originally said the strip was not powered through the 14/0.2 cable.
 
In my opinion you really shouldn't use cat5 cable, security cable or any cable smaller than 0.5mm2 for running the power to the pixels if it is more than a metre or 2. Once you get past a few metres it is just about a necessity to start using heavier cable like decent sized figure 8 cable.
It is the voltage at both ends of the pixels when the pixels are all on white that is the governing factor as to whether you're going to have problems. The Ink1003 is a special case as it has a built in regulator and can probably handle a lot more voltage fluctuation before the 1st pixel after a gap experiences problems.

@logan . Did the test sequence you were running include sections when all the pixels turn on to 100% white as that is where the greatest voltage drop will occur and this will cause a potential latchup as the pixels turn on and then there is insufficient voltage for them to receive any further valid data.
 
AAH said:
It is the voltage at both ends of the pixels when the pixels are all on white that is the governing factor as to whether you're going to have problems.....
Click to expand...

Alan this has got me a bit confused. It sort of implies that as long as my strip of pixels is powered adequately at the start (so power injected at start of strip) and is not overly long so there is minimal voltage drop along the length of the strip then it doesn't matter how long the cable sending the data from the controller to the start of the strip is.

I think I must be missing something.
 
AAH said:
@logan . Did the test sequence you were running include sections when all the pixels turn on to 100% white as that is where the greatest voltage drop will occur and this will cause a potential latchup as the pixels turn on and then there is insufficient voltage for them to receive any further valid data.
Click to expand...

Yes from memory it was when the lights went to White that it all locked up so it is most likely the insufficient voltage as you suggest. This year I'm planning to use a lot more power injection in my display particularly as Ray has those 3core T connectors where the centre connector is 2core for power injection.
 
BundyRoy said:
AAH said:
It is the voltage at both ends of the pixels when the pixels are all on white that is the governing factor as to whether you're going to have problems.....
Click to expand...

Alan this has got me a bit confused. It sort of implies that as long as my strip of pixels is powered adequately at the start (so power injected at start of strip) and is not overly long so there is minimal voltage drop along the length of the strip then it doesn't matter how long the cable sending the data from the controller to the start of the strip is.

I think I must be missing something.
Click to expand...

Data suffers a similar issue as voltage due to the resistance of the cable and other electrical factors, so the longer the length the weaker the signal will get and be more effected by any interferance.
This is why different cables will give different lengths for the signal.
 
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