Author Topic: Flickering!!!!! Help....  (Read 2880 times)

Offline fyb2000

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Re: Flickering!!!!! Help....
« Reply #15 on: December 03, 2016, 08:19:20 PM »
You letting a little rain slow you down? Pfff amateur!!!!
Just kidding, enjoy your evening


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Offline jnealand

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Re: Flickering!!!!! Help....
« Reply #16 on: December 03, 2016, 09:22:45 PM »
Since all your flickering seems to come from the second power supply I would check your voltages on that power supply.  I had some flickering and lockup, brought the string with problem inside to replace a pixel and could not make it fail.  Took it back outside and found my voltage was way too high.  Lowered the voltage, and have not had any further problems.
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Offline w8one

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Re: Flickering!!!!! Help....
« Reply #17 on: December 03, 2016, 10:27:29 PM »
The output you are using is a 2 wire bus or protocol. The data and ground have to go together from one to the next pixel. If only the data goes thru then half of the signal is taking a long trip back to the first power supply across to the second power supply back to the strip. Even the 1 wire protocols i2c has a ground.
If i told you to count how many snowballs went closer or farther than a stick laying on the ground and then took the stick away how would you know if they were close or far?
Quando omni flunkus moritati

Offline FIRECOP252

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Re: Flickering!!!!! Help....
« Reply #18 on: December 04, 2016, 12:26:18 PM »
Since all your flickering seems to come from the second power supply I would check your voltages on that power supply.  I had some flickering and lockup, brought the string with problem inside to replace a pixel and could not make it fail.  Took it back outside and found my voltage was way too high.  Lowered the voltage, and have not had any further problems.

Checked that, even replaced the PS thinking it was bad.  No dice.
LANCE

Offline fyb2000

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Re: Flickering!!!!! Help....
« Reply #19 on: December 04, 2016, 01:54:19 PM »
Were you able to have the ground wire from pixel 400 continuing to #401 and onward? Did that change anything with those effects you are having problem with?


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Offline FIRECOP252

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Re: Flickering!!!!! Help....
« Reply #20 on: December 04, 2016, 03:49:42 PM »
Yes I did and several other places were grounded.  I also common grounded the 2 distro boards also and still no change. 

I tried something different so I decided to use both outputs on the PiCap and put 400 pixels on each.  When I did this I started getting the flickering toward the end of both of the 400 pixels which tells me its a data issue im assuming.  Here is a couple of videos before I changed to the 2 outputs and you can see a simple effect like a 2 colored spiral it runs fine but something like the butterfly where there is a lot of color it starts flickering.  here is a couple of short videos to show the difference.

https://youtu.be/K-0961pbwXA

https://youtu.be/S_gpxatOuJQ

Offline fyb2000

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Re: Flickering!!!!! Help....
« Reply #21 on: December 04, 2016, 04:08:20 PM »
Yeah it's a long run for the data. Maybe a uamp in the middle of each string would boost the signal enough to get you going. At the end of the first movie it definitely looks like the signal received by the last pixels is not loud enough for them to know what to do with it.


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Offline FIRECOP252

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Re: Flickering!!!!! Help....
« Reply #22 on: December 04, 2016, 04:13:05 PM »
Yeah it's a long run for the data. Maybe a uamp in the middle of each string would boost the signal enough to get you going. At the end of the first movie it definitely looks like the signal received by the last pixels is not loud enough for them to know what to do with it.

They said they were successful running 800 pixels on 1 output connected end to end but im not having the same luck.

Offline K-State Fan

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Re: Flickering!!!!! Help....
« Reply #23 on: December 04, 2016, 05:30:36 PM »
What are you using on the second output?

Offline FIRECOP252

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Re: Flickering!!!!! Help....
« Reply #24 on: December 04, 2016, 05:31:28 PM »
400 pixels on each output

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Offline FIRECOP252

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Re: Flickering!!!!! Help....
« Reply #25 on: December 04, 2016, 05:54:23 PM »
Here is a longer video just taken this evening after I changed to 2 outputs.

https://youtu.be/1vyfncW-iZk

Offline fyb2000

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Re: Flickering!!!!! Help....
« Reply #26 on: December 04, 2016, 06:22:53 PM »
The signal degrades at each hop, no matter what. I have seen that kind of issues in my display with 6 props of 50 pixels being attached serially, 5 feet apart. Initially I had it on the last 2 props and by reducing the distance from ten to 5 feet that did the trick, but not always. For some reason, when it gets cold (California so cold means less than 45 Fahrenheit), those two props start misbehaving. Weird stuff like you are seeing,  pixels doing what they are supposed to do most of the time except when it gets more intense and they stop responding or do their own stuff. In your case it is quite intense and is really sad as you ended up building a beautiful tree with that pi cap


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Offline Emuney18

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Re: Flickering!!!!! Help....
« Reply #27 on: December 05, 2016, 06:28:35 AM »
What is the spacing between each of your pixels?  That might explain why some people get 800 and you can't get 400. I don't have a solution just an observation.


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Offline FIRECOP252

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Re: Flickering!!!!! Help....
« Reply #28 on: December 05, 2016, 06:29:44 AM »
3" spacing

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Offline corey872

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Re: Flickering!!!!! Help....
« Reply #29 on: December 05, 2016, 11:17:20 AM »
Some random thoughts FWIW...

As this is a megatree, 'data distance' should not be a huge issue provided the nodes are laid out smartly and the driving equipment is in or near the base of the tree.

Ideally, you would want plenty of grounds / power injection on decent gauge wire with relatively small runs.  The seemingly best set-up would be a control / power box at the base of the tree with equal wires running out to all points.  The key is that you want balance between the strings and controller.  You don't want any string or power injection point to be an extremely long run, or even notably longer than the rest.  You also don't want one power supply running ahead (or behind) the other voltage wise.

Have you tried a test sequence?  Either make one, or put the Pi in test mode (if applicable - honestly, I don't know much about that specific driver) The best sequence to me would be fade in / fade out each separate color and then fade in / fade out white.  Some sub-observations of that:

(further note I will use 'tend to' and 'seems to' a lot, as there can be an exception for almost every case)

Issues with red pixels seem to be associated with over voltage.  Red is generally the lowest voltage LED, so possibly more sensitive to input voltage 'too high' compared to green and blue LEDs.

White lock-up tends to be a ground issue.  Once all pixels switch on white, the power line droops to the lowest voltage level and ground line is loaded to the highest voltage level, while the high impedance data line remains relatively stable.  The ground line floating up can make the node unable to interpret data which means it stays locked on white.

Rainbows and flickering tend to be corrupt data, though it is unclear why some sequences work for you and some don't. I tried to eyeball the tree and estimate power consumption (patterns like 'snowflake' are generally pretty low power as most of the tree is black with only a few intermittent nodes lit, though other patterns which turn most nodes on bright and white or nearly so, can draw the most power)  Again, this power draw can expose imbalances in power distribution, high resistance joints, etc which can make the nodes behave unexpectedly.

Lastly, I would take a close look at your 'butterfly' effect if that is giving the trouble.  Pausing your video around the 19-20 second mark, I suspect this is the butterfly.  There is a very distinct section of the tree which is out, but at the bottom of that section, you seem to have 2-3 nodes on each strand which are working correctly.  (possibly 2-3 at the top too?)  I'm taking those nodes to be a couple at the beginning of one 100 node section and a couple at the end of the same section.  (and if the top 2-3 are OK, that would be the middle 4 -6 nodes)  Bad data would typically take out the whole string, not exactly the 'middle 96' nodes of multiple strings.  So it is almost as if that is what the tree is being told to do...possibly some set-up option incorrect, or some obscure little thing causing exactly that space to blank out.  It's also curious that the entire tree seems to flash red / green a few times.  Again, corrupt data tends to be really random, it would be very unexpected for 800 nodes, 2400 channels to ALL corrupt to a single color.

Anyway, the RGBW test pattern should narrow things down ...power, ground or data issue based on what you see.  Or if the test mode works fine, then it almost has to be a configuration issue.

Good Luck
« Last Edit: December 05, 2016, 11:24:01 AM by corey872 »
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