Strange Pixel Problem

[EmmienLightFan]

I have had this problem for a while now. It is really annoying me now though.

 

 

I have some "Pixel Icicles". These are icicle lights with every pixel controllable, not just every strand. There are 99 pixels in total, and 33 strands.

 

I inject power at the start, middle, then a wire goes from the middle to the end.

 

However, about 3/4 of the way through the pixels were turning yellow. I noticed it when I put a French Flag up. I put a bit of speaker wire running from the power supply to the pixels (Only on the +5v, no GND). This fixed it.

 

Today, I made all the pixels white, and the pixels are all red towards the end, but the last two strands were bright white. I thought that there must be a bad connection, so I re soldered and heatshrinked the cable between the two strands. I plugged them back in but now the first pixel on the second strand is a bright white, and the next is red. There is no connection between these two pixels. They are on the same strand and are connected just like they were when they were new. Also the lights are going yellow where I put the extra power injection in earlier, but they don't do it on the French flag sequence. 

 

I don't know how a pixel can be bright white but then the next one is a dim red colour.

[Ebuechner]

If there 5 volt pixels that's exactly what I did. But here's how I made mine. I went to the local hobby shop and got heavy duty servo wire. I use that in between my strands. I only power the strands from the input side to reduce power drop. So the power runs straight through the cable from strand to strand. I powered mine using 12 volts with a voltage regulator right at the first strand. By using 12 volts and voltage regulators to drop down to 5v you can easily inject power from one power source. But in your case you may be getting the signal all messed up. Try running a ground along with that positive that you used for the power injection. Remember your data line is also relying on the negative

Edited November 21, 2015 by Ebuechner

[EmmienLightFan]

I connected the ground wire and they are so much brighter when they are white!

However now I have another problem

[EmmienLightFan]

The pixels sometimes randomly start to flicker when they change colours. After a few seconds they settle down and are the correct colour. Whenever the pixels go red then turn off you can see a faint blue colour and sometimes the blue come son with the red making it look either purple or pink. 

 

And sometimes when they are off random pixels flash, similar to the problem with the Alphapix controller, but I have a Pixlite.

 

It looks terrible. It was better before with the red section in the middle.

[Ebuechner]

If they're flashing and doing strange things that's going to be your data being corrupt. Remember your data has to have a return line on the ground. If you can try adding a couple of gounds upstream from the problem. Also take a good look at your data line. If there's too much resistance on the ground while under load if it can cause problems with the data flow. I hit submit before I was done there. Same thing can happen if the voltage dips to the 2811 chip. It may have problems regenerating the signal if its low on voltage. And because you're operating at 5v there's not as much of a margin

Edited November 21, 2015 by Ebuechner

[EmmienLightFan]

Do you think that adding a ground wire right at the end of the line would help?

 

I now have ground connections all over the place.

[Ebuechner]

Without seen exactly what you're dealing with I don't know. Make sure you're checking your voltages all the way across. If it was me I would try to start from the input side and add power injection from that end and work my way through and see what it does. Try to work the problem one thing at a time so you know what works and what doesn't

[Ebuechner]

To add you need to check your voltages under load not static. You may start off with 5 volts but if there's a lot of resistance in the line when they turn on you could drop to 3 volts.

[EmmienLightFan]

Ok. It is dark right now and FREEEEZING cold so I will do it tomorrow.

 

Where should I be checking the voltage? I don't want to have to keep splicing and soldering and using heat shrink to check.

 

And what do you mean by resistance?

[EmmienLightFan]

Somewhere I read that you need to inject ground only at the start of pixel strings, which I have not been doing. I don't see how it would make a difference as it connects to the string before as well so it would be the end.

[dgrant]

All electrical, the power wire must have a matching return wire otherwise its limited by whatever return path it can find. The circuit must make a roundtrip as such. When injecting power, always run both + and - wires to the injection points.

[EmmienLightFan]

All electrical, the power wire must have a matching return wire otherwise its limited by whatever return path it can find. The circuit must make a roundtrip as such. When injecting power, always run both + and - wires to the injection points.

 

On the AustralianChristmasLighting forums I read that you only need the +5v. All my pixels are wired like that. 

 

Do I have to have both on every connection? Can't I just do most?

[EmmienLightFan]

And howcome it was working before?

 

 

Before I added any grounds on top of the end, middle and start, everything was working fine, but there were some red sections. Now, when I add one extra three quarters of the way down it all stops working.

[Ebuechner]

That sounds like you connected something wrong.

[EmmienLightFan]

That sounds like you connected something wrong.

I don't think so. I will check again tomorrow.

[Ebuechner]

Let's start from the beginning and get a little background. What gauge and type wire do you have running from the controller. And how much wire is between the controller and the lights

[EmmienLightFan]

Let's start from the beginning and get a little background. What gauge and type wire do you have running from the controller. And how much wire is between the controller and the lights

The wiring is a huge, huge mess.

 

There are three wires going from the PSU/controller to the lights. One goes from the controller to the lights and is cheap RGB wire. I have no idea of the gauge. It is similar to the other wire though. It is about 2 metres long.

Then there's another bit of wire, which is speaker wire, which goes to the second power input of the pixels - well, it is two wires. I doubled it up because it is so thin! Also about 2 metres thin.

 

Then there are some scraps of nice expensive speaker wire I somehow ended up with going form the start to the middle, and at the middle it is split and goes to the pixels and a piece of thick 2 core mains cable which runs to the end. Each run of this is 2.5 metres.

 

 

I am unsure of the gauge of the speaker but the wire is, **Embarrassed face**  13 strands of 0.2mm speaker wire.

 

All the above has both + and - 

 

 

 

There is a bit of speaker wire going from the power supply to the end. This is only the +. This is both conductors tied together. This is about 6 metres long.

 

This is split and goes to pixels a little further in.

 

There is a bit of speaker wire going to a strand about 3/4 of the way through. This is also only + and is half of the speaker wire (I peeled it away) This is probably 5 metres long.

There is the other half of this wire with the - on it. It is the same length.

 

I have been referring to ground as - but I think that is wrong.

 

Right now the lights are showing a French flag and are working fine, however everytime it goes between sequences and the lights flash off and on, they go weird and shimmer then flash white for about 20 seconds, then stop and go back to normal. I will get video if I see it again.

 

https://www.instagram.com/p/-R85gQD0Pr/?taken-by=alpha_road_xmas

 

 

 

 

 

My power supply is 30amps.

Edited November 21, 2015 by EmmienLightFan

[Ebuechner]

So let's slow down and take a look at this. From your picture everything looks pretty bright. Before you start doing more power injection you should check to see if you even need it. If you don't have a volt meter you will have to get one. You want to start at the controller and check to see if you have enough voltage. Then check at the beginning of the light string. And keep on checking down the line. Now here's a tip to make this job easier. If you use a couple of pins you can stick the wire to make a connection for the voltmeter. Of course this will leave a little hole in the wire which you may want to put a small dab of glue on or silicone. Or not if your weather isn't an issue. From there you can decide if you're losing too much voltage due to resistance in the wire. I use 16 gauge wire between my lights and the controller. What I use is extension cord 3 wire outdoor type with a ground. The larger the wire the less resistance it has and more power can get through. Also don't forget to check all your basics. When your lights are acting up are you watching the visualizer to make sure it isn't something in the sequence. It would be a shame if you were chasing this problem and it was something silly going on in the computer

[EmmienLightFan]

Yes, I have a multimeter.

 

The pins thing is a good idea. If I put the two further away from each other then I don't think weather will be an issue. 

 

 

 

Do you think that voltage may be causing this issue?

And I will test it with the pixels on full white. This is the best thing to do isn't it?

Edited November 21, 2015 by EmmienLightFan

[EmmienLightFan]

I put the power injection where I put it to make the flag brighter. It is just after there where it was starting to go yellow, but none of it is yellow any more.