PIR to SAMD21 to WS28212b Fade Color 250730

Projects Programming
30

When I find this happening to me, if it is not an out-of-array-bounds value, then the (in-bounds) pixel value of less than 0 or greater than 255 will cause a "blink/flash"

The "< or > value" occurs most when I am using an incrementing statement to cause another value to decrement (the reds increment causing blue to decrement, and vice versa).

This is my result for smooth red-mag-cyn-blu-cyn-mag-red transition.

#include <FastLED.h>
#define DATA_PIN 4
#define NUM_LEDS 299
#define COLOR_ORDER GRB
#define MAX_BRIGHT 128
CRGB leds[NUM_LEDS];

unsigned long timer, timeout = 10;  // regulate color step change
int red = 1, grn, blu, dir = 1, buttonPin = 2;

void setup() {
  pinMode(buttonPin, INPUT_PULLUP);
  FastLED.addLeds<WS2812, DATA_PIN, COLOR_ORDER>(leds, NUM_LEDS);
  FastLED.setBrightness(MAX_BRIGHT);

  while(digitalRead(buttonPin)) {}; // wait for button press LOW
}

void loop() {
  runSAMD21();
}

void runSAMD21() {
  if (millis() - timer > timeout) {  // control when each color change occurs
    timer = millis();                // reset timer for next color change
    red += dir;                      // inc/dec red color value
    if (red == 0 || red == 255) {    // when color value is at a boundary...
      dir = -dir;                    // ... change direction
    }
    blu = 255 - red;                      // complement red color value for blue
    for (int i = 0; i < NUM_LEDS; i++) {  // count through all pixels
      leds[i] = CRGB(red, grn, blu);      // update buffer for all pixels
    }
    FastLED.show();  // show new color
  }
}