large matrix and what to use..

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razataz327

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HI my name is Garnet .. I am planning to build a large matrix using
DC5V WS2812B led pixel strip,IP68 30 pixels/m.



The size will be around 8ft long by 4ft high so about 2700 pixels. From wha I have read I would need 3 teensy 1000 per unit and 3 ocotws2811. Is that correct.
This is new to me so am trying to do a lot of reading and understanding some of it.
I will want to expand my system at a later date.
Thanks very much for your help … great site you have .. the information is overwhelming at times … but is fun to read.

Garnet
 
Hi again. I am also wondering how to run the matrix with a sd card connected to the teensy. I would download the files on the card then not needing a pc to run the show. Similar to the t-8000 pixel led controller. What is the maximum distance the teensy can be from the matrix? I live in Canada and the teensy may have to be in the garage so it wont freeze up during the winter.
Any help would be appreciated.
Thanks
Garnet
 
razataz327 said:
From wha I have read I would need 3 teensy 1000 per unit and 3 ocotws2811. Is that correct.
Click to expand...

Three can certainly do it. But just 1 is probably enough.


razataz327 said:
Hi again. I am also wondering how to run the matrix with a sd card connected to the teensy. I would download the files on the card then not needing a pc to run the show.
Click to expand...

Maybe this will help?

http://community.arm.com/groups/embedded/blog/2014/05/23/led-video-panel-at-maker-faire-2014

Since that blog was written, the SD card playing has become a regular example included with the library.

After you install Teensyduino (and choose OctoWS2811 in the optional library install step), just run Arduino and open it with File > Examples > OctoWS2811 > VideoSDcard.

What is the maximum distance the teensy can be from the matrix?
Click to expand...

Well, that's a complicated question. TL;DR = longer distance is increasingly pushing your luck!

The main distance issue is getting the power supplied located close and connected with enough short, large diameter wire. Power delivery to large LED projects is always the most difficult part.
 
Hi Garnet,

You say you want an 8 ft x 4 ft display with about 2700 pixels? If I use 8n * 4n = 2700 I get n=9.2 so about 74 pixels horizontally (9.2 pixels per foot * 8 feet) and 36 pixels vertically (9.2 pixels per foot * 4 feet), which works out to a pixel every 1.3 inches (3.3 cm), which roughly corresponds to 30 pixels / meter. Are these the numbers you're using? Does it have to be exactly those dimensions and spacing? Having 32 or 40 vertical pixels (e.g. something divisible by 8) will make your life much easier.

My guess is you think you need 3 Teensy 3.x's to drive this array based on this page https://www.pjrc.com/teensy/td_libs_OctoWS2811.html saying 1000 LEDs per Teensy 3.0?

What are you planning on displaying? A single image, a new images every few seconds, or 30 frames per second video? If you're not going to do full video then you easily run this whole project with a single Teensy 3.1, with each leg of the OctoWS2811 adapter controlling 4

Regarding placement, the datasheet for Teensy 3.1's brain (the Freescale MK20DX256, at https://www.pjrc.com/teensy/K20P64M72SF1.pdf) says it's OK down to -40 C / -40 F and a web search says people frequently use SD cards below freezing with no issues (http://www.pentaxforums.com/forums/6-pentax-dslr-discussion/178947-sd-cards-low-temperatures.html) so for simplicity I'd try keeping the Teensy + hardware close to the LEDs.

If you do have problems at below freezing temperatures it should be pretty easy to make a simple heater with something like a big 1/2 or 1/4 Watt resistor (100-1K, depending on how hot you need it to get) running off the 5V LED power lines.
 
HI thanks very much Paul and potatotron for the replies and links. Yes the size of 4 x 8 was an estimate... I was going to use the 30 pixels/m sets I have. I think they will be ok as this will be viewed from the outside of my garage to the driveway .. which is 40ft long. I see some are using 60pixels /m. What are you thoughts on the fewer pixels but long viewing distance? I will want to be using video but am concerned of the pixel spacing. I will probably build it and see what it looks like.. can do images and cartoons instead. I will make it divisible by 8 as you suggest.
Power is not an issue as I have a solar system on my house with very large batteries that store the power. I have all the amps I need for 5 or 12 volt dc.
Garnet
 
What are you thoughts on the fewer pixels but long viewing distance?
Click to expand...

If it were me I'd start out with fewer pixels. Increasing the density from 30/meter to 60/meter will mean 4x more LED cost, power consumption, circuit complexity, etc. so I'd only do that if I had to.

Power is not an issue as I have a solar system on my house with very large batteries that store the power. I have all the amps I need for 5 or 12 volt dc.
Garnet
Click to expand...

Very cool. Definitely use the 5V lines for the LEDs; their maximum rating is 7V so 12V would probably do bad things to them.
 
Hi I have looked at the links and am ready to order but want to make sure I get it right. I will need 3 Teensy 3.1 and 3 octo ws2811.. and one wiz820+sd adapter. Is this correct?
Thanks for your help.
Garnet
 
razataz327 said:
Hi I have looked at the links and am ready to order but want to make sure I get it right. I will need 3 Teensy 3.1 and 3 octo ws2811.. and one wiz820+sd adapter. Is this correct?
Thanks for your help.
Garnet
Click to expand...

I'd definitely use the Teensy 3.1 for your project instead of the 3.0, but it's hard to say how many of them you'll need until you're further along. Since you're just starting out, it will be much less complicated to drive all the LEDs with a single Teensy instead of trying to synchronize multiple MCUs.

Having said that, of course you should buy multiple Teensys; they're great and you can do infinity things with them.

Regarding the other parts, this page https://forum.pjrc.com/threads/2663...-three-boards-(OctoWS2811-Teensy3-1-Wiz820-SD shows how to connect those 3 boards together so it's definitely possible.

Good luck with your project, I look forward to seeing it in action.
 
Also, as stated on Paul's large matrix notes you always needs spares, so having 3 (possibly 4) is a good idea. You can rewire the display to jump one of three dead teensy's but you can't rewire a display to jump one of one dead teensy's.

Apart from anything else a couple of spares will give you the option of a test one on the bench to experiment with where it's warm.
 
Hi thanks for the help.. the order has been placed and is on its way.. I will post pictures when it is finished .. also in the process of building a full size hover craft.. so lots of multitasking going on..
Garnet
 
Hi I have read the links and received my boards now. My question is can the boards be arranged in different stacking order or do they have to be done the way on you matrix build link? The only issue I see in changing them is the teensy switch may be hard to access. If changed I may be able to use shorter pins.
Thanks
Garnet
 
I am testing my pixel strips using a ;ed 2013-x dream color controller. It appears that 6 out of the 20 sets dont work. They flash once then that is it. Is there a way to test which pixel is not working?
I tried using the next one in line and so on.
The strips are ws2812b 30/m.
Garnet
 
Hi do I have to use all the 8 channels for the matrix? I only have 28 working strips so I was wanting to use 7 rows of 4 then when I get more strips I could add 4 more and use the last channel on the board. Then all channels would be used .. 4 rows of 60 pixels per channel.
Thanks
Garnet
 
Hi I was reading on the OctoWS2812 page and it says mid page under Video display example program that led height must be multiples of 8 in the software set up. I am able to use 5 or 6 channels now as the rest of my pixel strips dont work. I want to add more as I get them to the bottom rows with out rewiring the board. So I will have 6 channels with 5 rows of pixels in each for a total of 30.. Then I can add the 7th and 8th channel with 5 in each later for a total of 8 channels with 5 rows in each.
Garnet
 
The software will always send data to all 8 outputs, but you don't have to actually connect LEDs or send useful data in those other outputs. It's perfectly fine to use only 6 of the 8, and send all black or even random pixels to the 2 unused channels.
 
Hi I finally have the matrix finished. Have it all hooked up did the tests with teensy and octo sketch in Arduido works great. Go to use glediator or jinx.. cant get it to send anything out to teensy. Suggestions please what have I missed or done wrong.
Garnet
 
Hi asking again for some help on how to get Glediator to send data out to the teensy....all the test patterns work on the octo library but cant get any output working from the glediator.
Thanks
 
hey razataz327.
with jinx just wanted to check that u have patched the teensy in the output patch and output devices and then clicked on start output??
i havent had a problem using jinx as long as i did this
 
Nick1802 said:
hey razataz327.
with jinx just wanted to check that u have patched the teensy in the output patch and output devices and then clicked on start output??
i havent had a problem using jinx as long as i did this
Click to expand...



Hi I have done as you described and when I hit start output I get a box that says ERROR failed to open output. Please check your devices.
Maybe a com port is not available anymore or in double use.

More ideas would be great.. Almost there,,,I hope.. Need to have display working by tuesday.
Thanks
Garnet
 
i have never used glediator b4 so i cant help with that part.

what way are u talking to the teensy? via usb or network? i have only done this via network using artnet from jinx havent used any other ways yet.

but will be happy to help
 
Hi I am using the teensy with octo trying to use Jinx or Glediator. It appears we are missing some software so the teensy can interpret the data from Jinx or Glediator then put it to the leds... is that correct or what else am I missing?
Thanks
 
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