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Using Arduino => General Electronics => Topic started by: Qdeathstar on Apr 16, 2016, 04:08 am

Title: Impedance matching 4ft of 20awg wire
Post by: Qdeathstar on Apr 16, 2016, 04:08 am
Hello,

I am powering a long strip (50m) of ws2801 strips. About once an hour (but not on a schedule) I have a "blink" from my strips. It is annoying, so I've tried various things to silence them.

I installed filtering caps, and that seemed to make a difference.
I also removed a ground loop just tonight, and it seems like I might have gotten it down to once every two hours... but it's still there.


I installed 100ohm resistors between the controller and data, but now I've read that 100ohm is for cat5 cable's impedance and that other types of cable need difference resistor values based on impedance. I'm not sure if it will solve the blink or not, but I'm willing to give it a shot.

How can I calculate the impedance of 20awg copper?
Title: Re: Impedance matching 4ft of 20awg wire
Post by: DVDdoug on Apr 16, 2016, 07:00 am
Quote
How can I calculate the impedance of 20awg copper?
You can probably look-up the impedance for networking cable (CAT 5, etc.), but it depends on "construction".   That is, the space between the wires, etc.     And, I don't think it's an issue at 4 feet and at the data-rates you're working with.


It's probably not an impedance issue.    It could be software, or you may need to slightly slow-down the clocking.    (If you're using shiftOut() I'm not sure how to slow it down.)

When I had a problem with a shift register type interface, it turned out to be a noisy/marginal power supply.   And in my case, a larger capacitor on the voltage regulator for the LED driver stabilized the display.

With 50m of LED strips, you may have a power supply related issue too.
Title: Re: Impedance matching 4ft of 20awg wire
Post by: Wawa on Apr 16, 2016, 07:20 am
Curious how you have powered 50meters of digital LED strip (post a diagram).
Shouldn't you power that at least 2-3meters or so.
Leo..
Title: Re: Impedance matching 4ft of 20awg wire
Post by: Boardburner2 on Apr 16, 2016, 09:22 am
Curious how you have powered 50meters of digital LED strip (post a diagram).
Shouldn't you power that at least 2-3meters or so.
Leo..

Depends on illumination levels.

Guide i saw was every metre.
Title: Re: Impedance matching 4ft of 20awg wire
Post by: Boardburner2 on Apr 16, 2016, 09:24 am
Hello,



I installed 100ohm resistors between the controller and data, but now I've read that 100ohm is for cat5 cable's impedance and that other types of cable need difference resistor values based on impedance. I'm not sure if it will solve the blink or not, but I'm willing to give it a shot.

Have you tried a terminating resistor at the far end ?

Not sure if its needed though as the signal regenerates each pixel i think.

Some caps on the supply rails may help
Title: Re: Impedance matching 4ft of 20awg wire
Post by: OldSteve on Apr 16, 2016, 12:00 pm
..... or you may need to slightly slow-down the clocking.    (If you're using shiftOut() I'm not sure how to slow it down.)
It's not hard to override 'shiftOut()' by copying the function into the sketch file and introducing a delay between bits and/or between taking the clock high then low again.
It's a very simple function:-
Code: [Select]
void shiftOut(uint8_t dataPin, uint8_t clockPin, uint8_t bitOrder, uint8_t val)
{
    uint8_t i;
    for (i = 0; i < 8; i++)
    {
        if (bitOrder == LSBFIRST)
            digitalWrite(dataPin, !!(val & (1 << i)));
        else
            digitalWrite(dataPin, !!(val & (1 << (7 - i))));
        digitalWrite(clockPin, HIGH);
        digitalWrite(clockPin, LOW);
    }
}
Title: Re: Impedance matching 4ft of 20awg wire
Post by: Boardburner2 on Apr 16, 2016, 12:06 pm
Hello,

I installed filtering caps, and that seemed to make a difference.

Do you have the option of trying it powered by batteries ?

In the past i have used a 6V LA cell as a 'capacitor' to fault find troublesome supplies.
Title: Re: Impedance matching 4ft of 20awg wire
Post by: Qdeathstar on Apr 16, 2016, 01:45 pm
I have it powered every four meters. I am using one 100amp server supply. I don't think power is nessarily an issue (at full brightness everthing is bright white, not yellow). I have installed a line filter on the mains side of the transformer and 100uf capacitors everywhere I inject power to the strips. I am going to install ferrites there as well.


I think powering it it off of batteries would require a lot of batteries.


where would the terminating resistor go? what value? I hear something about a 1k between data and clock, but I didn't trust the source. I am using FastLED and have slowed down the data rate to 1mhz.


I notice that when I turn on mains powered light fixture closer to the strip, I get a blink.
Title: Re: Impedance matching 4ft of 20awg wire
Post by: Boardburner2 on Apr 16, 2016, 01:53 pm
I notice that when I turn on mains powered light fixture closer to the strip, I get a blink.
That would imply its an interference problem.

Perhaps moving the strip away from any electrical sources would narrow it down.

In #4 i mentioned caps, i meant distributed along the strip.

50 m long makes a good aerial, distributed caps across the rails may help
Title: Re: Impedance matching 4ft of 20awg wire
Post by: Qdeathstar on Apr 16, 2016, 02:52 pm
Should I put the caps voltage to ground? I'd need a axial cap like a resistor because there is not a lot of room in my aluminum channel. Maybe I should ground the channel (not to psu ground but to earth)

I can post a time lapse video of the blink it that will help.

Terminating resistor sounds like a easy thing to try. Could you elaborate on that
Title: Re: Impedance matching 4ft of 20awg wire
Post by: Boardburner2 on Apr 16, 2016, 03:38 pm
Should I put the caps voltage to ground? I'd need a axial cap like a resistor because there is not a lot of room in my aluminum channel. Maybe I should ground the channel (not to psu ground but to earth)


I was thinking Supply to ground, just an idea though.


Terminating resistor sounds like a easy thing to try. Could you elaborate on that
Don't think it will make a difference , i made an incorrect assumption initially.

The signal gets regenerated each led.

Do they blink when steady state ? Ie with no spi signals sending.

EG turn them on then disconnect the spi and clock signals.

Simpler test than soldering a load of caps.

I have installed a line filter on the mains side of the transformer and 100uf capacitors everywhere I inject power to the strips. I am going to install ferrites there as well.

100 uF implies electrolytic.

I was thinking of something with a low ESR, 1uF ceramic or similar.
Title: Re: Impedance matching 4ft of 20awg wire
Post by: MarkT on Apr 16, 2016, 04:18 pm
50m of anything is going to pick up a lot of interference, You probably need to to electrically break up
that long string to reduce the interference, which really means treating as a set of shorter strips and
driving each separately / in parallel.

But then you have to synchronize each portion of course.

Is the run one long straight run?  That's probably at risk of damage in the next thunderstorm if so too
Title: Re: Impedance matching 4ft of 20awg wire
Post by: Boardburner2 on Apr 16, 2016, 04:24 pm
50m of anything is going to pick up a lot of interference,

I am struggling to understand the mechanism.

For all the leds to blink at once.

They are all independently controlled local to the LED.

I wonder if the chips have some sort of reset internally i do not know about.
Title: Re: Impedance matching 4ft of 20awg wire
Post by: Qdeathstar on Apr 16, 2016, 05:54 pm
One chip boosts the signal of the next chip so I'm assuming
50m of anything is going to pick up a lot of interference, You probably need to to electrically break up
that long string to reduce the interference, which really means treating as a set of shorter strips and
driving each separately / in parallel.

But then you have to synchronize each portion of course.
Any way around that.

Quote
Is the run one long straight run?  That's probably at risk of damage in the next thunderstorm if so too
Are there solutions for this? It's not all in a strait run. 10m max straight run. I had 10m set up outside before for about a year, and it was still going strong.. Even after severe weather/hurricanes.


Title: Re: Impedance matching 4ft of 20awg wire
Post by: Qdeathstar on Apr 16, 2016, 06:01 pm
I was thinking Supply to ground, just an idea though.


Don't think it will make a difference , i made an incorrect assumption initially.
I would still like to try it. Someone said it worked well for them, but there wasn't enough detail. 1k across data and clock is what the said, but is that across one another or to ground?

Quote
The signal gets regenerated each led.

Do they blink when steady state ? Ie with no spi signals sending.

EG turn them on then disconnect the spi and clock signals.
I haven't tested this. But if I set up the LEDs to only get written once in setup, will that achieve the same thing?

Quote
Simpler test than soldering a load of c
100 uF implies electrolytic.

I was thinking of something with a low ESR, 1uF ceramic or similar.

I will try some of those as well.
Title: Re: Impedance matching 4ft of 20awg wire
Post by: Boardburner2 on Apr 16, 2016, 06:37 pm
I would still like to try it. Someone said it worked well for them, but there wasn't enough detail. 1k across data and clock is what the said, but is that across one another or to ground?

Probably data to ground and clock to ground.

I did this with a neopixel strip which has only 1 signal though.

Values , hard to say its suck it and see with an oscilloscope really, tweak until ringing is reduced.

But if you are able to control your strip OK its not necessary.
Once the first LED gets a good signal the rest of the strip regenerates the signal anyway.
Normally only a problem with long data feed wires.

I haven't tested this. But if I set up the LEDs to only get written once in setup, will that achieve the same thing?


The reason i suggested it is once they are on , physically disconnect the signal wires.

That may eliminate any possible glitches from the arduino end being the culprit.
Title: Re: Impedance matching 4ft of 20awg wire
Post by: Qdeathstar on Apr 16, 2016, 07:11 pm
Well, I will try that but I've noticed if you touch data and clock lines you can get led strips to light up at random, I I think disconnecting the data and clock lines will introduce noise that will change things from the get-go.

I also have breaks in the line about 1/2m in length every 10m or so... Maybe I should put a resistor there (though it would be difficult)
Title: Re: Impedance matching 4ft of 20awg wire
Post by: Boardburner2 on Apr 16, 2016, 07:22 pm
Well, I will try that but I've noticed if you touch data and clock lines you can get led strips to light up at random,


You act as an aerial ant put out random noise.
That noise will be faithfully amplified all the way up the chain until a pixel interprets it as data.

1K to ground on both signals should fix that, preverably right next to the strip input.

Putting resistors anywhere past the first pixel may be a bad idea. possibly damage the amp output of the previous pixel that way.
Title: Re: Impedance matching 4ft of 20awg wire
Post by: Qdeathstar on Apr 16, 2016, 08:02 pm
Glad I asked before I tried ;).
Title: Re: Impedance matching 4ft of 20awg wire
Post by: Qdeathstar on Apr 16, 2016, 08:03 pm
You act as an aerial ant put out random noise.
That noise will be faithfully amplified all the way up the chain until a pixel interprets it as data.

1K to ground on both signals should fix that, preverably right next to the strip input.

Putting resistors anywhere past the first pixel may be a bad idea. possibly damage the amp output of the previous pixel that way.
How do the terminating resistors work then?
Title: Re: Impedance matching 4ft of 20awg wire
Post by: Boardburner2 on Apr 16, 2016, 08:11 pm
They are there to match the characteristic impedance of the cable to the load.

Without them reflections occur.
This distorts the signal.

With a square wave that appears as ringing which can cause clocking errors.



Eg a video cable with an impedence of 50 ohms should be terminated with 50 ohms.

Likewise an audio cable is normally terminated with 600 ohms.

Pixel to pixel distance is so short to make them unnecessary between pixels.
Title: Re: Impedance matching 4ft of 20awg wire
Post by: Boardburner2 on Apr 16, 2016, 08:16 pm
I should add that it is essential to avoid ground loops for this to work properly.

I think disconnecting the data and clock lines will introduce noise that will change things from the get-go.

I also have breaks in the line about 1/2m in length every 10m or so... Maybe I should put a resistor there (though it would be difficult)
Unplugging the arduino psu would be just as good i think to avoid the soldering iron.

Your earlier offer of a video may be helpful, if only to see the physical layout.
At 50M length a circuit diagram does not always tell the whole story.
Title: Re: Impedance matching 4ft of 20awg wire
Post by: Qdeathstar on Apr 16, 2016, 09:20 pm
Ok, I will take a video tonight and YouTube it
Title: Re: Impedance matching 4ft of 20awg wire
Post by: Qdeathstar on Apr 17, 2016, 06:19 am
As promised, video. This is a ten second clip of one of the blinks. I recorded video for about 2.5hrs, and got three blinks, but this is one. (they all look roughly the same). I have it play twice, once it real time, and one slowed down 20x. You can see the blink "start" at the end of the strip, and work its way back toward the middle.

https://www.youtube.com/watch?v=Ad3DHnSiE1k (https://www.youtube.com/watch?v=Ad3DHnSiE1k)

I also got a rough schematic. The red arrows represent data and clock flow, i've labeled the MCU's location, and the blue dots represent power injection points. I have those protected with ptc fuses and filter noise out with caps.

http://s22.postimg.org/7av1gye4x/Image2.png

hopefully a video is worth infinate words.
Title: Re: Impedance matching 4ft of 20awg wire
Post by: Wawa on Apr 17, 2016, 07:34 am
You can see the blink "start" at the end of the strip, and work its way back toward the middle.
I think that means that you can rule out data and clock line problems.
Data/clock signals can only move forwards.

I would think it's a power problem. Spikes from long supply lines. Too fast for normal electrolytic caps.
I would start with a 5volt TVS diode across the supply at the very end of the strip.
And if problems persist, some more at various other easily accessible points on the strip.
Leo..
Title: Re: Impedance matching 4ft of 20awg wire
Post by: Qdeathstar on Apr 17, 2016, 07:49 am
thanks for your response, the supply voltage is 12v, so should I get a 12v one?

I also see they can be bidirectional or unidirectional, does it matter which I get?
Title: Re: Impedance matching 4ft of 20awg wire
Post by: Wawa on Apr 17, 2016, 09:08 am
Yes. 12volt TVS for a 12volt strip.
Uni-directional. Cathode (ring) to +12volt.

e.g this one.
http://nz.rs-online.com/web/p/tvs-diodes/6295254/
Leo..



Title: Re: Impedance matching 4ft of 20awg wire
Post by: Boardburner2 on Apr 17, 2016, 01:46 pm
When you said blink i assumed you meant off.

Were the leds at full brightness when that happened ?

The fact that all the leds kept the same colour makes me suspect that was caused by a sudden burst of power.

EDIT

I suspect the percieved traveling of the lights is an artefact of the video recording.
Title: Re: Impedance matching 4ft of 20awg wire
Post by: Qdeathstar on Apr 17, 2016, 03:24 pm
the leds were not at full brightness. they were at 10 percent.  I think they probably get to full brightness during the flash. what do you mean by "artifact". what do you think it actually looks like? even at full speed you can kinda see the last five or so pixes go wonkers, followed my more than half...

thanks

Title: Re: Impedance matching 4ft of 20awg wire
Post by: Boardburner2 on Apr 17, 2016, 03:34 pm
Video is scanned from the top down so if at the time of the flash the scan is half way down that frame does not 'see, it, the next frame picks it up however.

This gives the perceived effect of movement where there is none.

A similar faster effect occurs in the horizontal scan direction.

Stop motion, (frame by frame) is needed to be sure, that event is just too fast.


Does your power supply allow the output to be floating, that is not connected or referenced to mains earth.

Lab supplies normally do this but i am not sure about server PSU's

EDIT

Trying to video with the camera on its side may give more insight.
Title: Re: Impedance matching 4ft of 20awg wire
Post by: Qdeathstar on Apr 17, 2016, 04:23 pm
Video is scanned from the top down so if at the time of the flash the scan is half way down that frame does not 'see, it, the next frame picks it up however.

This gives the perceived effect of movement where there is none.

A similar faster effect occurs in the horizontal scan direction.

Stop motion, (frame by frame) is needed to be sure, that event is just too fast.


Does your power supply allow the output to be floating, that is not connected or referenced to mains earth.

Lab supplies normally do this but i am not sure about server PSU's

EDIT

Trying to video with the camera on its side may give more insight.
hmm. interesting. I will try to record again later tonight. I recorded at 60fps, and the blink seems to take about half a second to propogate. Maybe I'll try recording at 120fps. And sideways.


I am not sure about the power supply.

Here is the link:
http://www.amazon.com/HP-1200W-Power-Supply-500172-B21/dp/B007YW9OJU?ie=UTF8&psc=1&redirect=true&ref_=oh_aui_search_detailpage (http://www.amazon.com/HP-1200W-Power-Supply-500172-B21/dp/B007YW9OJU?ie=UTF8&psc=1&redirect=true&ref_=oh_aui_search_detailpage)
Title: Re: Impedance matching 4ft of 20awg wire
Post by: Boardburner2 on Apr 17, 2016, 04:33 pm
hmm. interesting. I will try to record again later tonight. I recorded at 60fps, and the blink seems to take about half a second to propogate.


My suspicion is that whole blink lasts only a few milliseconds.

I suspect that psu is mains grounded.

Do you have a mains isolating transformer you can borrow.
Big yellow thing often found on building sites.
Title: Re: Impedance matching 4ft of 20awg wire
Post by: Boardburner2 on Apr 17, 2016, 06:54 pm
as an afterthought , do you know what your electric utility supply type is ?

TN-S  ?  TN-C ?  , something else
Title: Re: Impedance matching 4ft of 20awg wire
Post by: MarkT on Apr 17, 2016, 09:05 pm
Looks like your setup is very much an antenna, you will need to break it up into shorter sections separately
driven to avoid susceptibility to airborne transients. Possible some high-speed logic opto couplers (not
ordinary ones, way too slow) inbetween separate sections to pass on the signals?

Am I right in assuming the strips are not near any other metal parts of the building?

Basically you are hoping to run effectively a single unshielded 5V logic circuit spread over 50m up on
a roof, which is pretty crazy - no EE would ever imagine that could work reliably outside of a faraday cage
chamber.  Its going to behave like an ad-hoc short wave antenna and pick up who knows what.
Title: Re: Impedance matching 4ft of 20awg wire
Post by: Qdeathstar on Apr 17, 2016, 09:57 pm
as an afterthought , do you know what your electric utility supply type is ?

TN-S  ?  TN-C ?  , something else
Ehhh.. It's 120/240 single phase. Dominion Power is the power company. How would I find that information, and how would I go about getting it.


Mark the strips are ran inside of aluminum Chanel that is glued with double sided 3m tape to metal flashing.

Title: Re: Impedance matching 4ft of 20awg wire
Post by: Qdeathstar on Apr 17, 2016, 09:58 pm
My suspicion is that whole blink lasts only a few milliseconds.

I suspect that psu is mains grounded.

Do you have a mains isolating transformer you can borrow.
Big yellow thing often found on building sites.
I know it's not recommended but if I cut the ground lead off the transformer would that do anything to isolate the ground? I have the transformer plugged into a power conditioner.
Title: Re: Impedance matching 4ft of 20awg wire
Post by: Boardburner2 on Apr 17, 2016, 10:36 pm
chamber.  Its going to behave like an ad-hoc short wave antenna and pick up who knows what.
The flash on the video implies high power.

Unless someone is playing with nukes and i would think someone would have noticed, i suspect some sort of earth fault.

Not sure what though.
Title: Re: Impedance matching 4ft of 20awg wire
Post by: Qdeathstar on Apr 18, 2016, 12:04 am
What can I try? I'm going to give the tvs diodes a try first, but always like more options
Title: Re: Impedance matching 4ft of 20awg wire
Post by: Qdeathstar on Apr 18, 2016, 03:27 am
it seems you were right about the direction issue, Boardburner.  I am video taping horizontal, and the blink happend simultaneously. 

I had I zoomed in the corner expecting a certain result but did not get it. I am now zooming out to see how far the blink goes. I'll post an updated video.


the thing I shiuld mention again, is that I have it on only 10 percent of full brightness during the video, and when the blink happens, it seems like it goes to full brightness, but not brighter than that. Ofc, it happens so fast it's hard to be certain.
Title: Re: Impedance matching 4ft of 20awg wire
Post by: Boardburner2 on Apr 18, 2016, 11:59 am
Basically you are hoping to run effectively a single unshielded 5V logic circuit spread over 50m up on

I am starting to think this may be down to ground bounce type effect somewhere.

Either in the strip or psu.
Title: Re: Impedance matching 4ft of 20awg wire
Post by: Boardburner2 on Apr 18, 2016, 12:19 pm
I have the transformer plugged into a power conditioner.
What transformer ?, you have not mentioned this before.
Title: Re: Impedance matching 4ft of 20awg wire
Post by: Qdeathstar on Apr 18, 2016, 01:34 pm
sorry, used transformer/psu interchangeably. I have it mains >> conditioner >> psu
Title: Re: Impedance matching 4ft of 20awg wire
Post by: Boardburner2 on Apr 18, 2016, 09:24 pm
I know it's not recommended but if I cut the ground lead off the transformer would that do anything to isolate the ground?
If you have a TN-C electrical supply then earth and neutral are connected together anyway.

Lot of power in that flash, changing something could blow your strip.

Only solution i can think of is to use a CTE isolating transformer and derive a local earth.

For a test though you could try a battery and only illuminate a few pixels.
Dont forget to isolate the arduino as well.

Looking around i see that some of those supplies can be made to float by cutting links inside, i dont know your abilities though , those supplies can be lethal.
Title: Re: Impedance matching 4ft of 20awg wire
Post by: Qdeathstar on Apr 18, 2016, 09:38 pm
Ground and neutral are tied together at the panel by two ground rods and cold water pipe.


I head you mention an isolation transformer earlier... Something like this to try?

http://www.amazon.com/Precision-1604A-Single-Isolation-Transformer/dp/B000LDLF3M/ref=sr_1_3?ie=UTF8&qid=1461008046&sr=8-3&keywords=isolation+transformer




Also,I'm going to run it at full brightness today and see if I still get the blink, as I hadn't done that yet I just realized.
Title: Re: Impedance matching 4ft of 20awg wire
Post by: Boardburner2 on Apr 18, 2016, 10:15 pm
http://www.amazon.com/Precision-1604A-Single-Isolation-Transformer/dp/B000LDLF3M/ref=sr_1_3?ie=UTF8&qid=1461008046&sr=8-3&keywords=isolation+transformer

Possibly.

Need to know what type to sort out the earths.

My technical mains uses the CT type.

https://www.gstransformers.com/technical/110v-centre-tap-earth-55v-0v-55v.html
Title: Re: Impedance matching 4ft of 20awg wire
Post by: Boardburner2 on Apr 18, 2016, 10:19 pm
Ground and neutral are tied together at the panel by two ground rods and cold water pipe.

Cold water pipe is just to keep everything at the same potential for safety.
Unless your incoming water main is metal it improves nothing.

The presence of the two ground rods makes me think this is a rural rather than urban setting.
Possibly with overhead supply lines.
Can you say your geography. ?

Mark the strips are ran inside of aluminum Chanel that is glued with double sided 3m tape to metal flashing.


These strips can be used on roofs apparently , the architectural suppliers do exactly that.
Channel is of course earthed
Title: Re: Impedance matching 4ft of 20awg wire
Post by: Qdeathstar on Apr 19, 2016, 12:36 am
Maybe I need to earth my channels, as they are not currently.

In the United States NEC code requires at least be ground rod (local requires two) and requires cold water ground. My pipes go into the earth as metal.

I have overhead lines at 120/240 but those are atleast 40ft away from my lights, and there are no transmission lines for atleast 100ft, those are probably 11kv (but I'm not sure)

My nuetral has zero potential to earth ground. I am certain of that.
Title: Re: Impedance matching 4ft of 20awg wire
Post by: Boardburner2 on Apr 19, 2016, 12:43 pm
As a kid i had a party telephone that used to occasionally go ding.

I discovered that nipping outside and having a wizz on the earth electrode solved the problem.

Maybe a hosepipe would help ?
Title: Re: Impedance matching 4ft of 20awg wire
Post by: Qdeathstar on Apr 19, 2016, 01:32 pm
hmm. well, I would try pissing on it, but as its mounted upside down splashback is a real concern... what type of goggle do you recommend for this type of work?






Title: Re: Impedance matching 4ft of 20awg wire
Post by: Boardburner2 on Apr 19, 2016, 02:13 pm
, but as its mounted upside down

Well there is your problem, its not an earth electrode, its a lightning conductor.  :)
Title: Re: Impedance matching 4ft of 20awg wire
Post by: Qdeathstar on Apr 26, 2016, 06:40 pm
Turns out the simplest solution was to slow the refresh rate down. I was unaware that FastLED had an option to slow the refresh speed to below 1mhz. I have slowed it down to 1khz and now it blinks maybe once every two days, but only at the last 20 or so pixels. I'm going to try to add a timer to only refresh the less once every 2 milliseconds. That should get me down to 500hz. I think that will completely solve the problem.

Thanks for all the advice though. This is a solution, but maybe not the solution. :D
Title: Re: Impedance matching 4ft of 20awg wire
Post by: Boardburner2 on Apr 27, 2016, 12:40 am
Glad you found an answer that worked .

Maybe your origional idea of the signal lines was the problem.
to slow the refresh speed to below 1mhz. I have slowed it down to 1khz and now it blinks maybe once every
Missed that i think the max speed for neopixels is 800 KHz
Title: Re: Impedance matching 4ft of 20awg wire
Post by: Qdeathstar on Apr 27, 2016, 05:57 pm
Yeah, neopixels are ws2812. Ws2801 is good for 4mhz, but that requires an almost perfect environment. In most environments it's 2mhz, and on a run like this which is actually out of spec (finding that out now) it needs to be turned way way down.