LED Statue

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BuffaloFan32

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I am a novice when it comes to electronics but I bought an Arduino last year and love experimenting with it. Recently, I had an idea to cover a statue in LEDs and figured the easiest way to do that would be to use LED strips. The statue would be interactive and also be used to share information with the community. I am in the early planning stages but plan to start by replicating Paul Soffregen's project:

http://www.dorkbotpdx.org/blog/paul/maker_faire_2013

Do you have any suggestions for keeping costs down? My preliminary cost analysis is looking pretty steep. Also, I could really use any technical expertise you have to offer.

The statue is 4.5ft tall and 8ft long with an estimated total surface area of 11,048sq in. Since each LED strip has a surface are of about 19.5 sq in, I figure I need about 567 strips! This sounds really expensive. I read that the highest resolution I can acheive is with the 100 LEDs/m strips because the 144s are too close together lengthwise so that, when you line them up widthwise, they are further apart. At full on white, I estimate the strips would need 13kW. Do you know where I can find a power supply that can deliver that at 5V? Do you know how much it would cost?

I have lots of questions but I think the power supply is the best place to start.
 
That many LEDs will be blinding. Really, this is far too much. Nobody will be able to look at your statue, standing within a 50 foot raduis.

You should really scale back to 30/meter and try to craft a way to diffuse the light. Perhaps you could mount the LEDs slightly inside the statue and use an outer layer that will refract the light?
 
That would be a problem! Is there a way to dim the LEDs? Perhaps, by making them blink more slowly? I do not want to blind people but I do think resolution is important. Am I using the wrong type of LED? It seems like I have seen LED marquees around town these days.
 
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I have been reading that persistence of vision dimming techniques is not possible with these strips. Is that true? Do I need to go back to the drawing board? I could paint over the LEDs but I think that consuming less power in the first place would be a cheaper/more efficient way.
 
Ws2812 strips are serially updated at 800Khz (the older ws2811 ran at 400Khz). I've read that is too slow for normal POV displays.
 
I think that you may have confused persistence of vision with pulse width modulation when you are talking about dimming. I can't see a reason for high rates of refresh for POV here, the statue is a stationary display, right?

you can dim the led strips by changing the amount of R, G or B by playing around with these values you will see that, on a scale of 0-255 for each of the RG and B values full on white would be (255,255,255), a dimmer white would be (125,125,125). Full blue would be (0,0,255) and a dim blue might be (0,0,50) for example. Of course, this method can quickly run into difficulties with colours not being quite right, and so might be limiting. These are just for example. diffusion gives a nice effect, if you don't want to see the individual leds shining, such as a thin fabric or gardening fleece. Depends what lends itself to the situation. You also have not mentioned you power supply options for the strips. The ws2811 do work well on static display.

The above technique using the r g and b values with provide a dimmer / different colour (all depends on the library you are going to use as to what the actual coding would look like.
 
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If you haven't used these LEDs at all, my first recommendation is to buy a small quantity, like 1 meter or even just 5 LEDs, and simply give them a try. Especially for an art project, having a few real LEDs lit up will let you explore options for mounting them and diffusing the light. No amount of specs and pictures online can give you a real feel for what your project will really look like.
 
Thanks guys, I was confusing POV with pulse width modulation. Is dimming with pulse width modulation possible with these strips?

The biggest project I have done with LEDs so far is a matrix of 6x24 (I am obviously out of my depth here). It is pretty bright as the LEDs are only seperated by a few pin holes on the breadboard so I can see where a much bigger collection of them would blind people. Sorry, if I seem a little dense on this issue but it seems like you guys are saying the only ways to not blind people and have high resolution is to diffuse the light or use mortonkopf's color adjustments above (which sound like they would skew the colors). The reason I don't like the idea of diffusing the light is that it sounds like I would be wasting power and this thing is going to consume a lot of power.
 
mortonkopf said:
You also have not mentioned you power supply options for the strips. The ws2811 do work well on static display.
Click to expand...

I wondering about the power supply. Do you have any ideas? If I use the method that Paul used for his display at Maker Faire, I think I would need about 60 of those which seems unreasonable.
 
BuffaloFan32 said:
Is dimming with pulse width modulation possible with these strips?
Click to expand...

Yes. In fact, it's built into the controller inside each LED.

Using a library (or writing the code all from scratch if you like), you simply send a 24 bit color value for each LED. The LEDs automatically do the PWM internally.

Assuming you use a library like OctoWS2811, it's really very easy. You just use setPixel() to configure the color of LEDs, then show() to cause them all to update. The library takes care of communicating all the 24 bit color data and the LEDs automatically dim each LED element.

Again, my recommendation is to simply buy a small number of LEDs (Adafruit, Ebay, etc) and of course a Teensy and the Octo28 adaptor board. You'll learn far more in 20 minutes of simply playing with a small number of LEDs than you could get from countless hours of reading specs, web pages and forum answers. One Teensy, an Octo28 board, a 1 amp 5V supply, and a meter of LEDs isn't terribly expensive. Just do it! You'll be glad you did.
 
Thanks Paul...I am on my way to ebay right now. I am sure I will have more questions when all the parts get here but really appreciate your help so far.
 
Hello again,
You were right, I got a strip and a 5V supply and I have been learning a lot about the Teensey 3.1 and Octo adapter. Right now, I have 8 rows of 12 pixels arranged in a grid. Each row is controlled by a different pin on the Teensey. The Rainbow and BasicTest examples work great.

I edited the VideoDisplay example and Processing 2.2.1 movie2serial to fit my computer and LED layout. Half the time I run the movie2serial I get an error about COM7 not being found and the other half of the time a screen pops up with a tiny black square. Nothing seems to make it to my LED grid. Any suggestions for troubleshooting?

These are the edits I made to the movie2serial:
serialConfigure("COM7");
Movie myMovie = new Movie(this, "C:/Users/Jesse/Desktop/Bear.wmv" );
 
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When you get the error about COM7 not being found, is it present in Device Manager but not accessible by the program? If it's missing in Device Manager then the problem isn't with the application….
 
It is present in Devicce Manager. If I unplug the USD cord and then plug it back in again, I stop getting that particular error for a few runs but then I get the problem of the tiny black square with no video in the output box.
 
So, it seems like there is something wrong with my Processing 2 and how it talks to Java. All of the Example programs seem to work if they don't have any Java references.
 
The errors I am getting, beginning with: java.lang.RuntimeException: java.lang.RuntimeException: Framebuffer objects are not supported by this hardware (or driver)

seem to imply that my drivers are out of date. When I go to Intel (I have a Dell Inspiron running Windows Vista with 965 Chipset Family), the site says it cannot install drivers on this computer and that I should go to Dell and get their drivers. When I go to Dell, it says I have the latest driver (although it is from 2011). Do you guys have any suggestions?
 
I received some feedback from the Processing forum. They recommended I downgrade to Processing 1.5.1 but movie2serial still does not work. They think the problem is my graphics card and driver. Do you guys have any ideas? Should I just get a Beaglebone? Is it easy to run movie2serial from one of those?
 
Hello PJRC, I am still working on my statue as I have time and $$$. I have about 50 rows of LEDs on it so far.

In between working on the statue itself, I have been experimenting with the teensey and the lights. I would now like to be able to control my 8x12 grid from my Beaglebone so I can eventually replicate Paul's project:

http://www.dorkbotpdx.org/blog/paul/maker_faire_2013

I am a little overwhelmed by the code he included in the attachments. Is there some literature or tutorials for novices like me that I can use to build up to that?

Also, I am currently controling my beaglebone through a terminal on my Windows based laptop. Will I be able to control the beaglebone like that when it is hooked up to the USD hub:

Untitled.jpg
 
The C code I wrote for that project isn't very flexible. It was done hastily in the couple weeks before Maker Faire 2013. The LED array size is hard-coded (60 by 32) and not easy to change.

In an ideal world, there'd always be time to go back and make all code nice. But after Maker Faire, I worked on a lot of non-octows2811 improvements, and the 3.0 -> 3.1 upgrade, and porting many more older Arduino libraries, and then the audio stuff. Always so many things to do, never enough time for them all!
 
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