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#include <Adafruit_NeoPixel.h>
#define PIN 3
#define LEDCOUNT 23
#define SPEED 5
const uint8_t PROGMEM gamma[] = {
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2,
2, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 5, 5, 5,
5, 6, 6, 6, 6, 7, 7, 7, 7, 8, 8, 8, 9, 9, 9, 10,
10, 10, 11, 11, 11, 12, 12, 13, 13, 13, 14, 14, 15, 15, 16, 16,
17, 17, 18, 18, 19, 19, 20, 20, 21, 21, 22, 22, 23, 24, 24, 25,
25, 26, 27, 27, 28, 29, 29, 30, 31, 32, 32, 33, 34, 35, 35, 36,
37, 38, 39, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 50,
51, 52, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 66, 67, 68,
69, 70, 72, 73, 74, 75, 77, 78, 79, 81, 82, 83, 85, 86, 87, 89,
90, 92, 93, 95, 96, 98, 99,101,102,104,105,107,109,110,112,114,
115,117,119,120,122,124,126,127,129,131,133,135,137,138,140,142,
144,146,148,150,152,154,156,158,160,162,164,167,169,171,173,175,
177,180,182,184,186,189,191,193,196,198,200,203,205,208,210,213,
215,218,220,223,225,228,231,233,236,239,241,244,247,249,252,255 };
// Parameter 1 = number of pixels in strip
// Parameter 2 = pin number (most are valid)
// Parameter 3 = pixel type flags, add together as needed:
// NEO_KHZ800 800 KHz bitstream (most NeoPixel products w/WS2812 LEDs)
// NEO_KHZ400 400 KHz (classic 'v1' (not v2) FLORA pixels, WS2811 drivers)
// NEO_GRB Pixels are wired for GRB bitstream (most NeoPixel products)
// NEO_RGB Pixels are wired for RGB bitstream (v1 FLORA pixels, not v2)
Adafruit_NeoPixel strip = Adafruit_NeoPixel(LEDCOUNT, PIN, NEO_GRB + NEO_KHZ800);
byte stripBuffer[LEDCOUNT];
long currentPos;
long maxPos;
bool direction = true;
void setup() {
maxPos = (LEDCOUNT - 1) * 256;
strip.begin();
strip.show(); // Initialize all pixels to 'off'
}
byte cyclesToSkipDecay = 0;
#define DECAYCYCLESKIP 3
void loop() {
if (direction) {
currentPos += 4;
if (currentPos >= maxPos) {
direction = false;
}
} else {
currentPos -= 4;
if (currentPos <= 0) {
direction = true;
}
}
if (cyclesToSkipDecay == 0) {
decayLEDs();
cyclesToSkipDecay = DECAYCYCLESKIP;
} else {
cyclesToSkipDecay --;
}
drawDot(currentPos);
refreshLEDs();
//delay(SPEED);
}
void drawDot(long thePos) {
// first half
byte theLED = thePos / 256;
byte theBright = thePos ^ 256;
if (stripBuffer[theLED+1] < theBright) { stripBuffer[theLED+1] = theBright; }
theBright = 255 - theBright;
if (stripBuffer[theLED] < theBright) { stripBuffer[theLED] = theBright; }
}
void decayLEDs() {
for (int i = 0; i < LEDCOUNT; i++) {
if (stripBuffer[i] > 0) { stripBuffer[i] -= 1; }
}
}
void refreshLEDs() {
for (int i = 0; i < LEDCOUNT; i++) {
strip.setPixelColor(i,pgm_read_byte(&gamma[stripBuffer[i]]),0,0);
}
strip.show();
}
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