Need Help - Null Pixels!

[rmcjfrank]

Hi all, I have been working with LOR equipment for years, but have taken the DMX plunge over the last two years.  This year I got ambitious and decided to outline my house with lights.  OK, so everything worked good in test mode, but during some sequences, from time to time a few runs of smart pixels wouldn't turn off or change color like they should have (the entire strip, and it was random from from one run of the show to the next).  I realized I didn't have any null pixels, and a few of the strips had long lead lines (to get from the box to the first pixel) -- upwards of about 30-40 feet.  So I decided to add null pixels to all the runs 20 feet or longer -- that is where the problem came in. 

 

Equipment involved with the problem (most from HolidayCoro):

 

PC w/Windows 8.1 

LOR S4 software (songs converted to Intensity Files - smaller file/remove lag), sequence being run from the sequence editor

TP-Link 10/100 5 port switch (from HolidayCoro)

AlphaPix16 Controller (E1.31 network) - approximately 50 feet from computer

Light strips: 12v/2811 pixel strip (50 segments)

Pixels: 12v/2811 bullets, w/8" spacing (80 bullets)

Extension wire: 18ga/3 wire black jacketed extension wire (like the pigtail connectors)

 

I soldered in a null pixel about halfway (10 feet down a 20 foot leader line) -- of two different props, one a strip, and the other a run of bullets.  When I turned on the box, they weren't working right and were flickering.  I changed the setting on the AlphaPix to account for the null pixel, and now they were only flickering (in white, some colors don't flicker).  When I cut out the null pixel, the flickering stops -- put it back, it returns.  I am using spare 12v/2811 bullets as my null pixel for both the strip and the group of bullets.  Both have the same problem.

 

I even successfully fried one of the output chips (my carelessness), but now have it back to not having a null pixel anywhere.

 

Here are my questions:  

1) do I need null pixels in this situation -- better yet, how do I know if I need a null pixel?

2) what would make it flicker like that with the null pixel?

3) the only other thing I can think of is that a signal can go a good distance to the first pixel, but once a pixel gets the signal and has to forward it, there is a limit to how far it can send one -- does anyone know if that is the case?

 

I would appreciate any help/advice!  Hopefully the new output chip arrives soon as well!.

 

-- Rob

Springfield VA

[Dennis Laff]

How long are your light strings are you injecting power every 50 pixels

[saxon]

I am dealing with similar issue.

If you colors fade to a different color and begin to flicker as the run increases, it is most likely power drop. As dennis  asked, are you power injecting?

If a few random pixels stay on, over power problem. especially true with nodes (been my experience).

If pixels flicker AND act erratic, It is most likely data volt drop and being corrupt.

This was the case with me anyways

 

You are right, you can go much further from the board to first pixel than you can from pixel to pixel. 

 

Remember, if your null isn't placed right, you be regenerating a corrupt signal which does you no good.

 

EX:

I have a 13 foot extension from pixel to pixel which tested fine from the board but failed from fixture to fixture. I cut 3 feet off it and all was good. after that fixture I have a 16 foot extension which failed until I placed a null pixel half way (8').

[rmcjfrank]

Thanks!  Interesting enough, without the null pixel, ALL of my runs "work" without flicker -- however, I think some of the data isn't getting to the right place at the right time when a sequence is running.  For strips, I am injecting power for runs over 50, but for the bullets, I have runs of 70, 80, and 90 without any power drop-off (and am told that I don't need to power inject those unless runs are over 100).

 

It seemed so weird that without a null pixel, the 50 pixel run 20 feet away from the controller worked fine in test mode, but with the null pixel placed halfway down, it flickered in test mode.  I thought maybe it was my soldering work, but it happened the exact same way on more than one.

 

Do you think that a distance of 10 feet from one pixel to the next is too far?  Would I be better with putting in two for a run of 20 feet? (one every 6.6 feet to the first set of "real" pixels).

[saxon]

Sounds like injection is fine (check with volt meter) with the strips. The nodes really don't need injection until 100. sounds like you may have a bad pixel you are using as a null -?. Another thing to consider is your connector on the last fixture that works properly. I had 2 bad connectors that tested fine in test mode until I moved them and then they flipped out. I replaced them and fixed my problem, maybe look to your connection.

If possible, can you connect your fixture together with out your extension?

 

As I mentioned until I cut one of my extensions DOWN TO 10', I had issues. So, from personal experience with the strips you have I would say 10' is the limit. I would definitely add 2 nulls for a 20' run from pixel to pixel. But from controller to first pixel you would probably be ok (my Sandevice would have no problem), not sure on the AlphaPix.

[Darryl Lambert]

Usually if they flicker with white but not with red, green, blue, it's a power issue. Best to check with a meter. The 20 foot 18g extension combined with the fact that they have 8" spacing ( 8" x 79 spaces = 52.67 feet ) would have me leaning that way. It could be that the little bit of extra power consumed by the null is dropping the voltage below the minimum.  

They usually recomend no more than 10' after the first pixel & Since a null is just a pixel that is not lit, I would only go 9' to be safe. There's a bunch of different factors that could affect the data.

Do these lines run close to any other power cords? I'm not familiar with the alphapix line of controllers. Maybe they can't output as far as some of the others. I have 4- 6804's & on one of them I have 17' of extension to start then a 10' extension between the 2 windows. No problem but on another one I have only a 10' extension to start & I had to put a null pixel in because that window was acting funny.

 

If possible I would do as Saxon suggested & try your prop with no extension. Then If ok try with no extension & the null. Still ok try only 10' of extension. It's going to be a PITA to do put it's better to get it resolved now. What I did with the null was to put a male & female plug end on them. It makes it alot easier to pop them into a run that way ( I only buy 5' & 10' extensions for this reason )

[Dennis Laff]

Not to change the subject but Darryl that idea of a male and female end on a null pixel seems like a great idea.

[saxon]

 These are the null pixels I am using, with male and female ends at $1 a pop.

 

3 Wire

http://www.aliexpres...2279633328.html

4Wire

http://www.aliexpres...2280784357.html

 

.

[Darryl Lambert]

Thanks

It's like how the chinese invented gunpowder. It came to them in a flash.

 

 

 These are the null pixels I am using, with male and female ends at $1 a pop.

 

That figures. The chinese saw them on my house & now they're getting all the $$$

[saxon]

 

straight stole your idea!! you were probably hacked.

[Darryl Lambert]

I don't know about being hacked. My computer would of had to be on my roof to see them!

 

I bet you it was that chubby guy in the red suit that was on my roof Dec.25th.

[Ebuechner]

I had roughly the same problem with the same equipment. Do not put a null pixel in between the controller and the first set of pixels. When going from one set of pixels to the next put a null pixel in the line about every 5 feet and that should get you taking care of. The controller can transmit the signal much further than a pixel can.

[sax]

I know this is about the pixcon 16, but I want to throw some info your way to alternatives.

Many discussions here about power injection and cable length....type of cable etc. I don't think I am alone in wanting my display to be less expensive, easy to put up, take down....parts easily accessed and element building to be quick, easy and cheap. Whew.

With that goal in mind I wanted my pixels to use similar components I had already purchased for dumb RGB. So 4 pin.

I used to make extension cords but purchasing premade is worth it. So I wanted to use premade cables.

To keep expenses down I wanted to be able to use maximum distance extensions. 25 footers!! This reduces the null pixels.

I use sans devices controllers. I also use 400 watt supplies....more pixels. I use China components.

I have to be honest and say my first attempt was utter failure. The setup worked perfect in the summer for testing but once in the yard I had flickering. It is difficult to troubleshoot in my yard in fall due to rain. But to correct this I went to 20' runs with a null. Later I found out that a component could be replaced in the E682 to allow the data to go further. It was a simple resistor network pack that cost less than a dime....I replaced all of them and now I get 25' extensions between my null pixels.

So, with the sans devices controllers...I have the 682 and 6804...I am able to have the setup I wanted.

25' between null pixels

Off the shelf cables

Able to purchase premade null pixels (as a side note you can also purchase single pixels with cables on it already for the same price)

Able to purchase pixels with the ends soldered on for me.

I was troubleshooting burnt strip pixels last night and discovered that I can even have 2 ribbons connected without issue. I thought for sure I would lose color on the second strip but it stayed constant. I don't need that but it opens possibilities.

So seeing your issue with flickering my first thought was data signal. Strange that a null introduces the flicker. I am able to get 25' with my nulls....20' without the component replacement. I would think 10' on any controller would be possible.

I too would systematically test to find the cause. If you have bullets, you could connect them, tell the controller there is a null and see if it causes issues. Of course 4" is not much of a test. But testing your null pixels was the goal....

I have 5' extensions. I would test in that increment.

Good luck. I am sure the fix will be found.

Sax

[rmcjfrank]

UPDATE:  so, I still don't have null pixels installed, and when I ran the Halloween show last night, I was having whole strips staying on or not responding correctly -- no matter how far from the controller (some are only a few feet).  Got me thinking about another troubleshooting step.  So, I pulled out my Pixlite 16 from last year's mega tree, and put it in place of the Alphapix 16 -- worked like a champ!  

 

The issue seems to be the Alphapix 16 controller - anyone have similar issues with this controller, and any recommendations?  I have the latest firmware (1.03 -- 1.04 isn't posted yet).

[Ebuechner]

I got caught up in the hype about the Alphapix controller. I also have the pixlite controller. I am NOT impressed with the Alphapics controller other than it has a fancy screen. It seems to have less User Options and more bugs. I do have mine working but it took a little more finesse. I made sure to test mine with real length cables. I pre measured and handmade custom length cables for my needs and tested it so I don't have any surprises. I'm glad I did I had a few problems. But my pixlight keeps chugging along and working just fine. But from here on in for more flexibility I'm going to be building E1.31 Bridge kits with pixel extenders. That way I don't have to worry about a single null pixel. All of my display items can then be operated off of cat 5 cable with almost no distance concerns

[DocBrown86]

I am having a similar issue. Also using the AlphaPix 16 and smart pixel strips from holiday coro. I haven't added null pixels, and the runs that are further away seem ok. Strangely the ones of medium distance are staying on or "freezing" at random points, lag when motion is programmed, and stay locked until random points when they will shut off... No idea what to do. Shouldn't be voltage, wouldn't that mess up the first and/or furthest ones?

They work fine in test mode, and occasionally (very rarely) respond correctly. Not sure what to try next to get the lag out...

[rmcjfrank]

Try the 1.04 firmware. It fixed most of my issues.

I have runs of 40+ feet that work great with the Pixlite.

[DocBrown86]

I upgraded from the 2.00 to 2.01 and it solved all the animation issues! Still occasional lag with random strips shutting off...nowhere near as bad as it was! Still though, I need it to work 100% every time...

[rmcjfrank]

Yeah, mine was fixed most of the time...but not 100%.   I abandoned the AlphaPix for the PixLite because of that.

[DocBrown86]

I want to do that, but that's an expensive move to abandon a 2-week old $200 controller for another $220 controller