WS2812 led strip

[sthomas229]

Hi there - after some help with led strip strip ws2812b, using the fastled libray and a nano. I have 6 strips in a tower, and trying work out how to flash the leds in row and coulums thinking of an array for ledstrip 1 (leds 1-8) colour blue, ledstrip 2 (9-17) etc, just after ideas ?

[Deva_Rishi]

@b707

are going to connect each strip to its own pin or will make a rows and columns with a single strip?

does that actually matter ?

@sthomas229

thinking of an array for ledstrip 1 (leds 1-8) colour blue, ledstrip 2 (9-17) etc

Simplest solution would be just the single output pin and address sections of it for every column.
Alternately, you can even create a 2 dimension array for led output buffer, and reference it to FastLED as if it is a 1 dimension array,

#include <FastLED.h>

// How many leds in your strip?
#define NUM_LEDS 40

#define DATA_PIN 7

// Define the array of leds
CRGB leds [6] [NUM_LEDS /  6];

void setup() { 

	LEDS.addLeds<WS2812,DATA_PIN,RGB>(leds,NUM_LEDS);
}

Just make sure that you never write beyond the bounds of the array (for 1 or 2 dimensions that is always true)
or your program will crash

[b707]

@Deva_Rishi

does that actually matter ?

probably not.
I agree, my comment was useless, so I'll remove it

[Deva_Rishi]

@b707

my comment was useless,

Well the option exists,

[sthomas229]

Thanks - was going to use just one pin, then could have them going in rows as well as up, and the just use a difernet array

[Grumpy_Mike]

I once had to do this for a question, where the user wanted to connect up various strips together. These included two circular displays. They wanted to make the lit LEDs follow a pattern, so I came up with this diagram showing the real pixel values and their virtual pixel equivalent.

I think you need to do the same sort of thing with what you want to do.

[sthomas229]

That a simlar thing to what I trying to, so how did get the cicles to do I differnet thing to the others ?

[Grumpy_Mike]

See if this post helps:-

How to divde an LED Strip into groups to display effects?

But my problem is still that I don't know how to assign the effect to the LED group. I told you that in reply #4. If you don't understand what I said then ask specifically about what I said that you do not understand. Alternately if you can't understand what I said try this other approach. Basically you have to use virtual pixel numbers to define the effect and then convert them to physical pixel numbers to set the colour of them in the library. You can do this with a look up table, which…

[sthomas229]

Thanks just the sort of thing I was looking for.