colorChase

Projects Programming
1

Hello all,

I am not a code-savvy person (yet!), and this is my first Arduino project, so forgive any basic questions. I am using Adafruit LPD8806 Digital RGB LED strips -- actually, just two pixels at this point -- and trying to separate the test code into different portions to help me learn more.

The strandtest code I grabbed online was:

#include "LPD8806.h"
#include "SPI.h" // Comment out this line if using Trinket or Gemma
#ifdef __AVR_ATtiny85__
 #include <avr/power.h>
#endif

// Example to control LPD8806-based RGB LED Modules in a strip

/*****************************************************************************/

int nLEDs = 2;
int dataPin  = 2;
int clockPin = 3;
LPD8806 strip = LPD8806(nLEDs, dataPin, clockPin);

void setup() {
#if defined(__AVR_ATtiny85__) && (F_CPU == 16000000L)
  clock_prescale_set(clock_div_1);
#endif

  // Start up the LED strip
  strip.begin();

  // Update the strip, to start they are all 'off'
  strip.show();
}


void loop() {

  // Send a simple pixel chase in...
  colorChase(strip.Color(127, 127, 127), 50); // White
  colorChase(strip.Color(127,   0,   0), 50); // Red
  colorChase(strip.Color(127, 127,   0), 50); // Yellow
  colorChase(strip.Color(  0, 127,   0), 50); // Green
  colorChase(strip.Color(  0, 127, 127), 50); // Cyan
  colorChase(strip.Color(  0,   0, 127), 50); // Blue
  colorChase(strip.Color(127,   0, 127), 50); // Violet

  // Send a theater pixel chase in...
  theaterChase(strip.Color(127, 127, 127), 50); // White
  theaterChase(strip.Color(127,   0,   0), 50); // Red
  theaterChase(strip.Color(127, 127,   0), 50); // Yellow
  theaterChase(strip.Color(  0, 127,   0), 50); // Green
  theaterChase(strip.Color(  0, 127, 127), 50); // Cyan
  theaterChase(strip.Color(  0,   0, 127), 50); // Blue
  theaterChase(strip.Color(127,   0, 127), 50); // Violet

  // Fill the entire strip with...
  colorWipe(strip.Color(127,   0,   0), 50);  // Red
  colorWipe(strip.Color(  0, 127,   0), 50);  // Green
  colorWipe(strip.Color(  0,   0, 127), 50);  // Blue

  rainbow(10);
  rainbowCycle(0);  // make it go through the cycle fairly fast
  theaterChaseRainbow(50);
}

void rainbow(uint8_t wait) {
  int i, j;
   
  for (j=0; j < 384; j++) {     // 3 cycles of all 384 colors in the wheel
    for (i=0; i < strip.numPixels(); i++) {
      strip.setPixelColor(i, Wheel( (i + j) % 384));
    }  
    strip.show();   // write all the pixels out
    delay(wait);
  }
}

// Slightly different, this one makes the rainbow wheel equally distributed 
// along the chain
void rainbowCycle(uint8_t wait) {
  uint16_t i, j;
  
  for (j=0; j < 384 * 5; j++) {     // 5 cycles of all 384 colors in the wheel
    for (i=0; i < strip.numPixels(); i++) {
      // tricky math! we use each pixel as a fraction of the full 384-color wheel
      // (thats the i / strip.numPixels() part)
      // Then add in j which makes the colors go around per pixel
      // the % 384 is to make the wheel cycle around
      strip.setPixelColor(i, Wheel( ((i * 384 / strip.numPixels()) + j) % 384) );
    }  
    strip.show();   // write all the pixels out
    delay(wait);
  }
}

// Fill the dots progressively along the strip.
void colorWipe(uint32_t c, uint8_t wait) {
  int i;

  for (i=0; i < strip.numPixels(); i++) {
      strip.setPixelColor(i, c);
      strip.show();
      delay(wait);
  }
}

// Chase one dot down the full strip.
void colorChase(uint32_t c, uint8_t wait) {
  int i;

  // Start by turning all pixels off:
  for(i=0; i<strip.numPixels(); i++) strip.setPixelColor(i, 0);

  // Then display one pixel at a time:
  for(i=0; i<strip.numPixels(); i++) {
    strip.setPixelColor(i, c); // Set new pixel 'on'
    strip.show();              // Refresh LED states
    strip.setPixelColor(i, 0); // Erase pixel, but don't refresh!
    delay(wait);
  }

  strip.show(); // Refresh to turn off last pixel
}

//Theatre-style crawling lights.
void theaterChase(uint32_t c, uint8_t wait) {
  for (int j=0; j<10; j++) {  //do 10 cycles of chasing
    for (int q=0; q < 3; q++) {
      for (int i=0; i < strip.numPixels(); i=i+3) {
        strip.setPixelColor(i+q, c);    //turn every third pixel on
      }
      strip.show();
     
      delay(wait);
     
      for (int i=0; i < strip.numPixels(); i=i+3) {
        strip.setPixelColor(i+q, 0);        //turn every third pixel off
      }
    }
  }
}

//Theatre-style crawling lights with rainbow effect
void theaterChaseRainbow(uint8_t wait) {
  for (int j=0; j < 384; j++) {     // cycle all 384 colors in the wheel
    for (int q=0; q < 3; q++) {
        for (int i=0; i < strip.numPixels(); i=i+3) {
          strip.setPixelColor(i+q, Wheel( (i+j) % 384));    //turn every third pixel on
        }
        strip.show();
       
        delay(wait);
       
        for (int i=0; i < strip.numPixels(); i=i+3) {
          strip.setPixelColor(i+q, 0);        //turn every third pixel off
        }
    }
  }
}
/* Helper functions */

//Input a value 0 to 384 to get a color value.
//The colours are a transition r - g -b - back to r

uint32_t Wheel(uint16_t WheelPos)
{
  byte r, g, b;
  switch(WheelPos / 128)
  {
    case 0:
      r = 127 - WheelPos % 128;   //Red down
      g = WheelPos % 128;      // Green up
      b = 0;                  //blue off
      break; 
    case 1:
      g = 127 - WheelPos % 128;  //green down
      b = WheelPos % 128;      //blue up
      r = 0;                  //red off
      break; 
    case 2:
      b = 127 - WheelPos % 128;  //blue down 
      r = WheelPos % 128;      //red up
      g = 0;                  //green off
      break; 
  }
  return(strip.Color(r,g,b));
}

I figured it would be easy to edit out parts, but ran into an interesting issue. When I transfer only this much of the code...

#include "LPD8806.h"
#include "SPI.h" // Comment out this line if using Trinket or Gemma
#ifdef __AVR_ATtiny85__
 #include <avr/power.h>
#endif

// Example to control LPD8806-based RGB LED Modules in a strip

/*****************************************************************************/

int nLEDs = 2;
int dataPin  = 2;
int clockPin = 3;
LPD8806 strip = LPD8806(nLEDs, dataPin, clockPin);

void setup() {
#if defined(__AVR_ATtiny85__) && (F_CPU == 16000000L)
  clock_prescale_set(clock_div_1);
#endif

  // Start up the LED strip
  strip.begin();

  // Update the strip, to start they are all 'off'
  strip.show();
}


void loop() {

  // Send a simple pixel chase in...
  colorChase(strip.Color(127, 127, 127), 50); // White
  colorChase(strip.Color(127,   0,   0), 50); // Red
  colorChase(strip.Color(127, 127,   0), 50); // Yellow
  colorChase(strip.Color(  0, 127,   0), 50); // Green
  colorChase(strip.Color(  0, 127, 127), 50); // Cyan
  colorChase(strip.Color(  0,   0, 127), 50); // Blue
  colorChase(strip.Color(127,   0, 127), 50); // Violet

  // Send a theater pixel chase in...
  theaterChase(strip.Color(127, 127, 127), 50); // White
  theaterChase(strip.Color(127,   0,   0), 50); // Red
  theaterChase(strip.Color(127, 127,   0), 50); // Yellow
  theaterChase(strip.Color(  0, 127,   0), 50); // Green
  theaterChase(strip.Color(  0, 127, 127), 50); // Cyan
  theaterChase(strip.Color(  0,   0, 127), 50); // Blue
  theaterChase(strip.Color(127,   0, 127), 50); // Violet

  // Fill the entire strip with...
  colorWipe(strip.Color(127,   0,   0), 50);  // Red
  colorWipe(strip.Color(  0, 127,   0), 50);  // Green
  colorWipe(strip.Color(  0,   0, 127), 50);  // Blue

  rainbow(10);
  rainbowCycle(0);  // make it go through the cycle fairly fast
  theaterChaseRainbow(50);
}

void rainbow(uint8_t wait) {
  int i, j;
   
  for (j=0; j < 384; j++) {     // 3 cycles of all 384 colors in the wheel
    for (i=0; i < strip.numPixels(); i++) {
      strip.setPixelColor(i, Wheel( (i + j) % 384));
    }  
    strip.show();   // write all the pixels out
    delay(wait);
  }
}

I get an error reading 'colorChase' was not declared in this scope, but there is not instance of colorChase in the portions of the code I removed, nor is there anything different 'above' the portion I isolated. Did I do something wrong with the library, maybe? I have the LPD8806 library in both, so I am not sure what is different between the two, with regards to colorChase.

Any wisdom would be appreciated, thanks.

2

Since you deleted: void colorChase(uint32_t c, uint8_t wait) {. . .} what else would you expect?

I don't know what game is being played here.

.

3

These

#include "LPD8806.h"
#include "SPI.h"

require the libraries to be installed in the same folder as your sketch.
If you use

#include <LPD8806.h>
#include <SPI.h>

the SPI library will come from the core libraries folder, and you can have the other in your /libraries folder.
Then the call to colorChase will work correctly.

Plus what LarryD said - if try to use functions you deleted, things won't compile well.

4

The libraries were fine-- it turned out (forgive me, this was expressed to me as follows) that the compiler did not require colorChase to be declared before it was 'used' so to speak. So my assumption that it was not necessary just because it was 'later' in the code was mistaken.