FraKtus rants and fun videoz

After having discovered the Arduino and before attacking the network extension I wanted to create something fun with the board and the 8 by 8 LED tile.

So I came with the idea of using one old school plasma effect of ArKaos VJ and porting it to the Arduino.

Here is the result:

Basically there are 2 textures pre-computed at startup. They are moved on a circular motion.

The 2 textures are moved and summed and you obtain an height value for each pixel. To get a nice effect you then go through a color table that is also pre-computed at startup.

To have a nice rotation effect you shift the color table at each generation of a new image.

At the end of the video you have another simple loop I did to test my setup.

Here is the plasma code for the Arduino:

//
// Plasma generation for the Arduino and a RGB Serial Backpack Matrix from SparkFun Electronics
// Marco Hinic, built on top of the code of Ryan Owens
//

//Define the SPI Pin Numbers
#define DATAOUT 11//MOSI
#define DATAIN 12//MISO
#define SPICLOCK 13//sck
#define SLAVESELECT 10//ss

void LED_Setup()
{
//SPI Bus setup
SPCR = (1< 64 bytes
// 16 by 16 -> 256 bytes
// color table 256 bytes
//

#define PLASMA_W 8
#define PLASMA_H 8

#define TABLE_W 16
#define TABLE_H 16

unsigned char gPlasma[PLASMA_W*PLASMA_H];
unsigned char gTable1[TABLE_W*TABLE_H];
unsigned char gTable2[TABLE_W*TABLE_H];
unsigned char gColorTable[256];
float gCircle1, gCircle2, gCircle3, gCircle4, gCircle5, gCircle6, gCircle7, gCircle8;
int gRoll;

void Plasma_CalcTable1 ()
{
for (int i=0; i< TABLE_H; i++) { for (int j=0; j< TABLE_W; j++) { int index = (i*TABLE_W)+j; gTable1[index] = (unsigned char) ((sqrt(16.0+(PLASMA_H-i)*(PLASMA_H-i)+(PLASMA_W-j)*(PLASMA_W-j))-4) *5 ); } } } void Plasma_CalcTable2 () { for (int i=0; i< TABLE_H; i++) { for (int j=0; j< TABLE_W; j++) { int index = (i*TABLE_W)+j; float temp = sqrt(16.0+(PLASMA_H-i)*(PLASMA_H-i)+(PLASMA_W-j)*(PLASMA_W-j))-4; gTable2[index] = (sin(temp/9.5)+1)*90; } } } void Plasma_SetColor (int index, unsigned char red, unsigned char green, unsigned char blue) { unsigned char new_color = (red & 0xE0) + ((green & 0xE0) >> 3) + ((blue & 0xC0) >> 6);
gColorTable [index] = new_color;
}

double gRed, gGreen, gBlue;

#define color(u,a) (cos((u)+(a))+1)*127

void BuildColorTable()
{
double u;
int i;
for (i=0; i<256; i++) { u=2*PI/256*i; Plasma_SetColor(i,color(u,gRed),color(u,gGreen),color(u,gBlue)); } gRed+=0.05; gGreen-=0.05; gBlue+=0.1; } void Plasma_Setup () { gCircle1 = 0; gCircle2 = 0; gCircle3 = 0; gCircle4 = 0; gCircle5 = 0; gCircle6 = 0; gCircle7 = 0; gCircle8 = 0; gRoll = 0; for (int i=0; i

I bought a small Arduino board that has a small CPU to prototype some ideas about driving LEDs.

Here is the first test, it’s was quick to have something blinking!

I want to use that as a prototyping platform to develop a protocol to drive LEDs in a simpler way.

Today you drive LED or with DMX or with video converters. DMX is cool and inexpensive but difficult to setup and video converters are very expansive.

There should be a way to connect LEDs to a computer and having them recognized automatically by a VJ software…

If you are curious to see on how simple the code is, here it is:

// Writing to the RGB Serial Backpack Matrix from SparkFun Electronics
// Marco Hinic, built on top of the code of Ryan Owens
//

//Define the SPI Pin Numbers
#define DATAOUT 11//MOSI
#define DATAIN 12//MISO
#define SPICLOCK 13//sck
#define SLAVESELECT 10//ss

//Define the variables we’ll need later in the program
char color_buffer [64];

void setup()
{
//SPI Bus setup
SPCR = (1<