So my LED strips are almost here.

Archive FastLED Archive
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So my LED strips are almost here. Once they get here, I have a new project - I’m replacing all the electronics in my Daft Punk helmet, with 7 vertical strips of LEDS. I want to set them up as a matrix, of 7 x whatever. Any suggestions for making this happen? I seem to recall the Adafruit folks coming up with matrix functions for this situation, but I’d really prefer to work with FastLED for obvious reasons. :slight_smile:

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https://plus.google.com/114689543789013665296/posts/5Ato53LC8qb (explicit, dedicated led containers still a little bit out)

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The short version is this: define a function called XY, something like this.
byte gWidth = 8; // or however wide your array is.
int XY(byte x, byte y) {
return (y * gWidth) + x;
}

Then any time you want to deal with a pixel in any way, where you used to provide a direct pixel number, like this
leds[ {pixel-number} ]
instead use your new function and the X and Y coordinates:
leds[ XY( {x-coord}, {y-coord} ) ]

Basically, you now have a helper function which takes the X and Y coordinates you’re aiming for, and computes what pixel number that is.

It may come out upside down or rotated from how you expect, or you may need to deal with a “serpentine” (actually, “boustrophedon”) pattern, but as Dan said, this has been discussed here and a quick search should turn up useful results, and it’s pretty quick to adapt them to your setup.

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Here is some code Daniel helped me write months ago, and it’s a matrix! https://plus.google.com/105445034001275025240/posts/A6h5ZWwAjSw

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Well, it’s sort of a moot point now. I managed to completely screw up the visor while removing the tinting, and now I can’t wear it anymore. I am a sad panda. :frowning:

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if you get it back together, I did a matrix based on LPD8806 stris

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So I had a thought. Would I get better performance if I split the matrix into columns and used a different pin for each?

I’m doing a 7x32 matrix, and it would be trivial to split that up. the wiring would be a bit more complex, but it would let all my strips be oriented the same way. it would use 7 pins, probably pins 2 - 9.

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In the meantime, I’ve implemented a column copy and flip, so now I need to work on shapes, text, and scrolling. Text is going to be the hardest, especially if I want two sizes (3x5 and 5x7).

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It really depends on how you have the whole structure wired. My grid project uses pixels and every other row and is treated like the positive x and y quadrant…

//converts cartesian coordinates into a index into a linear array
//r is for rows c is for columns
uint8_t pixel(uint8_t r,uint8_t c){
if(r%2==1) //for the odd rows
{ return(c+((r-1)*num_columns)-1);}
else
{ return(num_columns-c+((r-1)*num_columns));}
}