# 8x8 RGB Matrix Fade Speed

Hi,

Read though madworms awesome thread and got my matrix working straight away. Now I'm trying the modify the code...

Original Code
int ctr1;
byte row;
byte led;

for(ctr1 = 0; ctr1 < 360; ctr1=ctr1+3) {
set_matrix_hue((float)(ctr1));
}
}

What I'm trying to do is have the code only run the fader_hue void, which I've done, and be able to control the speed of the fading with a pot connected to analog0. I can get it almost working by changing the for statement to read this:

int ctr1;
byte row;
byte led;
Micval = map(Micval, 0, 1023, 1, 100);
Micval = constrain(Micval, 1, 100);

for(ctr1 = 0; ctr1 < 360; ctr1=ctr1+Micval) {
set_matrix_hue((float)(ctr1));
}
}

The problem is that it runs through the whole fade animation and then updates the speed. This means that if Micval is 1 then it runs through the whole fade procedure (3-4 seconds) then updates the speed if Micval has changed. As Micval gets quicker is fades quicker and updates the fade speed quicker. What I want is for it to update the fade speed immediately after a new Micval is present.
Any Ideas?
Cheers

http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1215096929/0

You need to do the analogread() of the pot inside the for loop

Ah great, that worked perfecly. Now I can I can alter the rate of fading with an analog value.

What I'd like to do next is control the rate of colour change based on an analog value. Say if the analog value was under 100 then the matrix would just glow blue, and if it went up to say 700 then it would glow red. And as it went up from 0 to 700 the colours would change through the spectrum, blue to cyan to green to yellow to orange to purple to red. AND have the the speed of the fade change accordingly, 100 is a slow fade and 700 a fast fade.

I was thinking of having it as two functions, one that controls the colour change and another inside that changes the fade speed. I'm not quite sure how I'd do this but was wondering if anyone had a better idea before i invest dozens of hours into something that may not work at all.

cheers

The code I've gotten so far can adjust either the fade value or colour value, but not both at once. And when i change the colour value it stops fading, it's only when reset the colour change back to ctr2, ctr1, hue that fading works again.

void set_matrix_hue(int hue) {
byte ctr1;
byte ctr2;
for(ctr2 = 0; ctr2 <= __max_row; ctr2++) {
for(ctr1 = 0; ctr1 <= __max_led; ctr1++) {
}
}
}

int ctr1;
byte row;
byte led;
for(ctr1 = 0; ctr1 < 360; ctr1=ctr1+constrain((map(analogRead(1),0,1023,1,10)),1,10)) {
set_matrix_hue((float)(ctr1));
}
}

As you've seen, the set_matrix_hue() function is instantaneous.

If I understand you right, you need to write a function that fades from color A to color B ( on the 0...360 rainbow, where 360 is the same as 0 ).

You should modify the fader_hue() function, so it remembers the last color value and if the new value ( determined by the analogRead() ) is different, then fade to the new value using a for loop and the speed setting as you've done it already.

something like (pseudo code):

``````int new_color = analogRead(...);

if ( new_color < old_color ) {
...
for(ctr1 = old_color; ctr1 > new_color; ctr1=ctr1-speed) {
...
}
...
}

if ( new_color > old_color ) {
...
for(ctr1 = old_color; ctr1 < new_color; ctr1=ctr1+speed) {
...
}
...
}

if ( new_color == old_color) {
...
}
``````

Thanks for the tips, but I can't quite get it working. I've modified the fader parameter to fade in and out from black, and i can control the speed of that.

``````void fader(void) {
byte ctr1;
byte row;
byte led;

for(ctr1 = 0; ctr1 <= __max_brightness; ctr1++) {
for(row = 0; row <= __max_row; row++) {
for(led = 0; led <= __max_led; led++) {
set_led_rgb(row, led, ctr1, ctr1/100, ctr1/100);
}
}
}
for(ctr1 = __max_brightness; (ctr1 >= 0) & (ctr1 != 255); ctr1--) {
for(row = 0; row <= __max_row; row++) {
for(led = 0; led <= __max_led; led++) {
set_led_rgb(row, led, ctr1, ctr1/100, ctr1/100);
}
}

}
}
``````

In that example I can control the fade speed with analogRead(0), but not control the colour value with another ananlogread (1 for example) interger. If I don't have the ctr1 values in the set_led_rgb function then it won't fade, just sit at a constant colour. For example I tried something like this which didn't work

``````int a = constrain((map(analogRead(1),0,1023,1,10)),1,10);
int r = 0;
int g = 0;
int b = 0;
{
r= 100 -(2*a);
g=2*a;
b=0;
}
r=0;
g=100-(2*(a-50));
b=2*(100-50);
}
}
set_led_rgb(row,led,r,g,b);
``````

Again, hours of work and back where I started. Can fade in from black to a colour then back to black OR cycle through the rainbow but lose the fading in/out from black ability.

The work continues...
Re-reading through my posts, I may not have been descriptive enough about my program. What I'm after is the ability to control the colour and fade speed through two separate pots. Ie, pot 'a' would control the fade speed, from quickly fading from black to full brightness and back the black again. Pot 'b' would control the colour of the matrix, so that the colour could be changed regardless of the fade speed and vice-versa. Here's an example how what I've come up with.

``````void fader(void) {
int ctr1;
int a;
int r;
int g;
int b;
for(ctr1 = 0; ctr1 <= 15; ctr1++) {
set_matrix_rgb(ctr1,ctr1/a,ctr1/a);
}
for(ctr1 = 15; ctr1 >= 0; ctr1--) {