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WS2811 Pixels with Black Wire - Which wire is which?


cancolby
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Hello. I recently purchased this: 

 

http://www.aliexpress.com/store/product/100pcs-DC12V-12mm-WS2811-led-pixel-node-with-all-black-wire-20AWG-IP68-rated/701799_1032319604.html

 

A strand of 100 WS2811 12v LED pixels. The wire is all black. How do I determine which end of the strand is the start, and how do I determine which wire is Ground, Data, and +V?

 

Thanks.

Colby

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Look closely at the PCB, (good eyes or a magnifying glass will work here), where the arrows point toward the LED, that will be Pixel # 1. Looking at the PCB again, The 5v+ and ground, will typically be on the outside and the data wire is most times in the center. It's hard to make out, but it's silk screened onto the PCB.

 

Another thing, on the IN side, the middle wire will be marked with DI typically and on the OUT side, it will be marked DO.

 

Take a look at this photo: 

https://www.dropbox.com/s/clrleqjhs1lpgbb/Pixel%20PCB.pdf

There are red arrows pointing to arrows on each pic. The top one will be the in side. You can easily see the arrows and the markings "5V" and "DI". On the second pic, it's a little harder to make out, but the arrow is pointing away from the LED. If you look closely enough, you ban just make out the "DO" marking.

 

In my experience, the out side is typically on the WS2811 chip side. I'm sure it's not always like that, but the ones I've used are.

 

***Again, a magnifying glass is your friend here.*** The bullet style nodes are more difficult to pick out than the flat style, but it is possible.

Edited by Ron Boyd
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Thank you for the reply. I figured I would be looking inside the pixel node. Unfortunately the material surrounding the node is diffused… Do you have any recommendations for seeing past it? Sandpaper hasn't helped yet but perhaps I'll try slicing off a small sliver with a knife. I've attached a photo.

post-14324-0-72344700-1406049331_thumb.j

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look at a number of pixels (make sure you look at the same sides (look for the chip to give you orientation).  With a magnifying glass you should be able to put together a layout (each pixel will be the same as the others) as you may get a clear part in different places on different picels. 

If all else fails sacrifice one pixel and cut off the silicon.  (again use the chip as a guide for what side is what). DI is data in  DO is data out (going to the next pixel)  GDN is of course ground and the remaining will likely be marked 5V or 12V for positive.  If memory serves all of the pixels I have (purchased a different times from different suppliers) the chip is on the Data Out side, but be sure on your pixels.

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a trick I have used in the past to see past the diffused outside was to get the outside of the pixel wet with water and the lettering on the pcb is than easily read. you only need a magnifying glass to see the really small letters.

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Does anybody know how many WS2811 pixels I can safely string together? Can I do strands of 200 or 300?

 

Also, isn't it possible to use the auxiliary power port on a San Devices E682 to create some sort of mini ethernet switch or something to effectively daisy-chain multiple controllers?

 

Thirdly, isn't it possible to convert the ethernet cable coming out of an E682 into DMX to control standard DMX fixtures?

Edited by cancolby
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Does anybody know how many WS2811 pixels I can safely string together? Can I do strands of 200 or 300? Yes, but distance and power will be your determining factor. You will definitely need power injection. The rule of thumb for WS2811 is 50 pixels. I've read where some have gotten up to the mid to high 60s before injecting power, but I keep mine at 50. I am using 5v as opposed to your 12v, so these numbers may not be the same for you.

 

As far as distance, the rule of thumb here is about 15 ft. although again, some have been successful with further distance. If your 200 or 300 are strung, one string directly into the next, this figure only comes into play from 682 to first pixel. 

 

Also, isn't it possible to use the auxiliary power port on a San Devices E682 to create some sort of mini ethernet switch or something to effectively daisy-chain multiple controllers? This, I don't know about. Most of us that use E1.31 are also using an Ethernet switch when using more than one controller. Just plug in the Cat5e or Cat6 cable from PC to switch and plug the controllers into the switch. Just about any 10/100 switch should work.

 

Thirdly, isn't it possible to convert the ethernet cable coming out of an E682 into DMX to control standard DMX fixtures? There is not an ethernet cable coming out of the E682 that I know of and I have 2 in my setup. If memory serves, each port on the 682 can run DMX with a DMX controller. The E682 does not control the elements, just the element controller. That said, you can use a bridge.

On this page: http://www.diyledexpress.com/index.php?main_page=index&cPath=22&zenid=c6ca45e4267efa64be3d5ed1831b9621 there is the E1.31 to DMX Bridge in a kit form and a fully assembled and tested board. Basically, you plug this into the switch like any other E1.31 controller and have 6 outputs of DMX data. You can read how it works here: http://doityourselfchristmas.com/wiki/index.php?title=E1.31_Bridge

 

Hope this didn't confuse you too much and hope it helps.

Edited by Ron Boyd
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Also, isn't it possible to use the auxiliary power port on a San Devices E682 to create some sort of mini ethernet switch or something to effectively daisy-chain multiple controllers?

That's what I read, but I only have one E682 this year so I don't need to do that. You can get a cheap Ethernet switch that needs a 5v power supply, run the cable from the computer to 1 port, plug another port to the E682, and run other ports to your other E682 boards.

 

Thirdly, isn't it possible to convert the ethernet cable coming out of an E682 into DMX to control standard DMX fixtures?

Yes, but not the Ethernet cable. You'll use one of the output ports, which you will configure as DMX pixels. Then put a jumper in J22 for that port group. Connect your DMX cable data+ to the clock pin, data- to the data pin, and ground to the ground pin. See page 24 of the E682 manual.

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