Cutting pixel strings.....

[coasterbp]

So I just received my pixel strings from Ray and I'm ready to start mounting them to my frames. I want to cut them to length for each frame. I know that I can add extensions BETWEEN pixels, but as for the "end of the line", I want to be able to cut the string and end it.

But what can I do with the "left-overs"... Can that be the start of a NEW string and then add onto that as well?

Oh, these are WS2801, 4 wire pixels...

Thanks!

-=CoasterBP

[WilliamS]

You do not need a terminator at the end. When you end the string just seal it up and move on.

The left overs you can use as another string. The controller address what number the pixel is. The first pixel in the sting will automatically be #1 in the sequence of pixels. Easy as cake.

Say you cut of 10 pixels from say 15 strings to make the lenghts you want. You can attach all 15 of those 10 pixel strings into 1 long string and it will act as if it were alredy 1 string. Theres no magic to it.

This was a question I had in the past as well. Donny answered this for me about 5 months ago and after testing and reading how pixels work it just makes sense. To help out he made it make sense to me. The signal coming from your controller is 150 pixels in order. The first pixel takes its info and sends the left overs to the next. The second pixel cant see the first pixels signal becuase its already gone, so now the second pixel thinks its #1 and strips its signal and passes on the rest. #3 now thinks its number 1 and so on till it runs out of pixels or signal.

[Daryl Hurd]

It is just like any other type of wiring splicing. You can solder or crimp them together. No special wiring connections needed. Just make sure that the different pixels are the same voltage, IC chip and have same colored wiring. If you splice a WS2801 with a WS6803 pixel, the controller used to send the signal to them will not be able to send both signals.
-Daryl

[MikeyRo]

And aren't the pixels directional? Meaning the power supply has to come from a specific side of the chip/strip?

I am not sure what would happen if you turned one around, but I think I read the pixels were directional.

[-klb-]

Power is not directional. But data and clock are directional. But you need to know that to hook up to the controller to start with. The clock in and data in must wire towards the controller.

[Tim Fischer]

Will it hurt things if data is wired backward (mine don't have clock), or just not work until you switch it? I evidently got lucky when I wired my one string (more to come). There was no clear indication of which side was which - just bare wires on both ends.

[Steven]

MikeyRo wrote:

And aren't the pixels directional? Meaning the power supply has to come from a specific side of the chip/strip?

The power can be injected anywhere along the strip, and for long strips, is often inserted in more than one place to prevent unacceptable voltage drop.

However, the signal is directional. Each pixel as a "data in" and "data out" side.

[coasterbp]

Awesome. Thanks for everyone's help. It makes sense to me now. I'm glad that I can cut these strings to basically any size and still be able to use all the leftovers.... SWEET!

-=CoasterBP

[WilliamS]

It should not hurt the pixel if you get the clock or data backwards. As Ive done it a hundred times becuase china isnt always great at labels. In fact the 2801 strips I have also have the in/out backwards. So to send signal I have to send in the side that says output.

For attaching more in the series, you simply wire all connection from a to b. Power can come in from any side or like Steven said anywhere in the strip.

Give us some time and the ways to do it will be more clear. If you are not 100% certain you can do it, save your money and get the ready made, under warranty, LOR items. I cant say that enough. Light O Rama takes all the guess work out of it and they cover thier products.

[-klb-]

Tim Fischer wrote:

Will it hurt things if data is wired backward (mine don't have clock), or just not work until you switch it? I evidently got lucky when I wired my one string (more to come). There was no clear indication of which side was which - just bare wires on both ends.

There is always a chance of damage when two signal drivers are trying to drive the same wire. And, there is even a chance that the controller could be damaged. But probably better than 90% of the time, a brief out to out connection won't hurt much. And, I think the controller is likely to be better protected than the pixel. But, if you have a bad data out on the last pixel of your string, it is sort of a no harm, no foul situation... You weren't planning on a next pixel to use the data anyway.

[Tim Fischer]

Something I'd like to add to this discussion... I've had 600 or so TLS3001 pixels connected to an E681 and a 5V power supply for over a month. In the last week, 3 nodes have failed. The result is a series of random flashing by the pixels beyond the failed node. It's easy to find the culprit, it's always the last dark pixel before the lights that are blinking. So, you cut it out and reconnect the string and all is fine. But just be sure to locate and mark them before you power them down. I've had a couple behave this way, I disconnected the string and let them cool. Later I couldn't tell where the problem was. With one of them, I ran a chase sequence and the answer was obvious... it wasn't passing any data down the string. So far, out of 1000 pixels I've had 5 go bad. It's enough that I'll make spares for the display in case it happens during the show.

Jeff

That's a depressing ratio. Even more depressing that it takes out the remainder of the string and not just the single node. That could spell bad news on a mega-tree where accessing the nodes could be a real problem in-season.

Thanks for the info.

[flogger7]

How long are you typically running burn-in's for on new strips/pixels?

[Tim Fischer]

Jeff did you have them running 24/7? Solid or doing patterns, etc?

Just curious.

[Crazydave]

Quick question on pixels,

when you purchase pixels from Ray Wu....

are the ends of string terminated such that wires are only hanging off one end or

or do they have wires that hang off each end

For example:

do they look like this (where ==== is wire and =|= is a pixel

=====|=======|=======|===

or do they look like this

=====|=======|======|

My questions is because I want to have a pixel string that is say 170 pixels long, will I have to cut off the last pixel in order to splice in the addional pixels, or will I be able to simply splice the start of the additional string onto the end of the first?

[Tim Fischer]

Quick question on pixels,

when you purchase pixels from Ray Wu....

are the ends of string terminated such that wires are only hanging off one end or

or do they have wires that hang off each end

For example:

do they look like this (where ==== is wire and =|= is a pixel

=====|=======|=======|===

or do they look like this

=====|=======|======|

My questions is because I want to have a pixel string that is say 170 pixels long, will I have to cut off the last pixel in order to splice in the addional pixels, or will I be able to simply splice the start of the additional string onto the end of the first?

Mine have bare wires both ends.

Do note that due to voltage drop, you might not make it to 170 without multiple power injection points. Definitely not with 5V pixels.

Edited June 29, 2012 by Tim Fischer

[Steven]

So far using 5volts I think I'm getting about 42 pixels before there's an obvious color change toward blue.

I am curious as to why it's not a color change toward pink, since blue and green LEDs have a bigger voltage drop?