02- 8-Bit WS2812 RGB LED

參考資料：http://pizgchen.blogspot.tw/2017/04/ws2812-8-bit-2812-rgb-led.html

• 傳統方式要控制多顆 RGB LED 在電路接線和程式控制方面是非常煩雜的，然而使用內建 WS2812 晶片的 RGB LED 卻是簡單又方便，不管你要控制幾顆 RGB LED，都只要使用 Arduino 3 支腳位就足夠了。

• 8位 WS2812 5050 RGB LED 內置全彩驅動彩燈開發板

• 淘寶:https://world.taobao.com/item/541980677823.htm?fromSite=main&spm=a1z09.2.0.0.A2AvmF&_u=41lsjr25ba78

• 電路接線

• 用杜邦線依下表將 Arduino 與燈條連接起來：

• Arduino 燈條

• 5V VDC

• Gnd Gnd

• D6 DI

• 1. void colorWipe(uint32_t c, uint8_t wait) {

1. for(uint16_t i=0; i<strip.numPixels(); i++) { //strip.numPixels() LED個數-1

2. strip.setPixelColor(i, c);

3. strip.show();

4. delay(wait);

5. }

6. }

7. //由上可知，如果要在第一顆LED燈顯示紅燈，程式如下

8. // strip.setPixelColor(0, strip.Color(50, 0, 0)); // strip.show(); // delay(5000);

10. // Slightly different, this makes the rainbow equally distributed throughout

11. void rainbowCycle(uint8_t wait) {

12. uint16_t i, j;

14. for(j=0; j<256*5; j++) { // 5 cycles of all colors on wheel

15. for(i=0; i< strip.numPixels(); i++) {

16. strip.setPixelColor(i, Wheel(((i * 256 / strip.numPixels()) + j) & 255));

17. }

18. strip.show();

19. delay(wait);

20. }

21. }

23. // Input a value 0 to 255 to get a color value.

24. // The colours are a transition r - g - b - back to r.

25. uint32_t Wheel(byte WheelPos) {

26. WheelPos = 255 - WheelPos;

27. if(WheelPos < 85) {

28. return strip.Color(255 - WheelPos * 3, 0, WheelPos * 3);

29. } else if(WheelPos < 170) {

30. WheelPos -= 85;

31. return strip.Color(0, WheelPos * 3, 255 - WheelPos * 3);

32. } else {

33. WheelPos -= 170;

34. return strip.Color(WheelPos * 3, 255 - WheelPos * 3, 0);

35. }

36. }

上例中有用到下面呈現亮燈的函式，前者是固定顏色的顯示，後者則是以顏色變化來顯示。

• colorWipe(strip.Color(255, 0, 0), 500);

• rainbowCycle(20);

下例為「檔案」>「範例」>「Adafruit_NeoPixel」>「strandtest」的程式

#include <Adafruit_NeoPixel.h>

#ifdef __AVR__

#include <avr/power.h>

#endif

#define PIN 6

// Parameter 1 = number of pixels in strip

// Parameter 2 = Arduino 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)

// NEO_RGBW Pixels are wired for RGBW bitstream (NeoPixel RGBW products)

Adafruit_NeoPixel strip = Adafruit_NeoPixel(1, PIN, NEO_GRB + NEO_KHZ800);

// IMPORTANT: To reduce NeoPixel burnout risk, add 1000 uF capacitor across

// pixel power leads, add 300 - 500 Ohm resistor on first pixel's data input

// and minimize distance between Arduino and first pixel. Avoid connecting

// on a live circuit...if you must, connect GND first.

void setup() {

// This is for Trinket 5V 16MHz, you can remove these three lines if you are not using a Trinket

#if defined (__AVR_ATtiny85__)

if (F_CPU == 16000000) clock_prescale_set(clock_div_1);

#endif

// End of trinket special code

strip.begin();

strip.show(); // Initialize all pixels to 'off'

}

void loop() {

// Some example procedures showing how to display to the pixels:

colorWipe(strip.Color(255, 0, 0), 50); // Red

colorWipe(strip.Color(0, 255, 0), 50); // Green

colorWipe(strip.Color(0, 0, 255), 50); // Blue

//colorWipe(strip.Color(0, 0, 0, 255), 50); // White RGBW

// Send a theater pixel chase in...

theaterChase(strip.Color(127, 127, 127), 50); // White 閃爍

theaterChase(strip.Color(127, 0, 0), 50); // Red

theaterChase(strip.Color(0, 0, 127), 50); // Blue

rainbow(20);

rainbowCycle(20);

theaterChaseRainbow(50);

}

// Fill the dots one after the other with a color

void colorWipe(uint32_t c, uint8_t wait) {

for(uint16_t i=0; i<strip.numPixels(); i++) {

strip.setPixelColor(i, c);

strip.show();

delay(wait);

}

}

void rainbow(uint8_t wait) {

uint16_t i, j;

for(j=0; j<256; j++) {

for(i=0; i<strip.numPixels(); i++) {

strip.setPixelColor(i, Wheel((i+j) & 255));

}

strip.show();

delay(wait);

}

}

// Slightly different, this makes the rainbow equally distributed throughout

void rainbowCycle(uint8_t wait) {

uint16_t i, j;

for(j=0; j<256*5; j++) { // 5 cycles of all colors on wheel

for(i=0; i< strip.numPixels(); i++) {

strip.setPixelColor(i, Wheel(((i * 256 / strip.numPixels()) + j) & 255));

}

strip.show();

delay(wait);

}

}

//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 (uint16_t i=0; i < strip.numPixels(); i=i+3) {

strip.setPixelColor(i+q, c); //turn every third pixel on

}

strip.show();

delay(wait);

for (uint16_t 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 < 256; j++) { // cycle all 256 colors in the wheel

for (int q=0; q < 3; q++) {

for (uint16_t i=0; i < strip.numPixels(); i=i+3) {

strip.setPixelColor(i+q, Wheel( (i+j) % 255)); //turn every third pixel on

}

strip.show();

delay(wait);

for (uint16_t i=0; i < strip.numPixels(); i=i+3) {

strip.setPixelColor(i+q, 0); //turn every third pixel off

}

}

}

}

// Input a value 0 to 255 to get a color value.

// The colours are a transition r - g - b - back to r.

uint32_t Wheel(byte WheelPos) {

WheelPos = 255 - WheelPos;

if(WheelPos < 85) {

return strip.Color(255 - WheelPos * 3, 0, WheelPos * 3);

}

if(WheelPos < 170) {

WheelPos -= 85;

return strip.Color(0, WheelPos * 3, 255 - WheelPos * 3);

}

WheelPos -= 170;

return strip.Color(WheelPos * 3, 255 - WheelPos * 3, 0);

}

上例中有用到下面呈現亮燈的函數

• colorWipe(strip.Color(255, 0, 0), 500);亮燈

• theaterChase(strip.Color(127, 127, 127), 50); // White 閃爍

• rainbow(20);

• rainbowCycle(20);

• theaterChaseRainbow(50);

下例為呼吸燈製作(http://www.arduino.cn/thread-6115-1-1.html)

#include <Adafruit_NeoPixel.h>

#define PIN 6

#define MAX_LED 1

#define ADD true

#define SUB false

int val = 0;

boolean stat = ADD;

// Parameter 1 = ws2811级联数量

// Parameter 2 = arduino PIN

// 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( MAX_LED, PIN, NEO_RGB + NEO_KHZ800 );

void setup()

{

// 初始化库

strip.begin();

// 发送数据，默认每个点的颜色为0，所以初始的每个点都是不亮的

strip.show();

}

void loop()

{

// 设置颜色，参数为 R G B，范围0-255

uint32_t color = strip.Color(val, val, val);

// 设置某个点的颜色，实验中只有一个，所以只控制第0个点

strip.setPixelColor(0, color);

// 下面是产生呼吸灯效果

if(val>=255)

stat = SUB;

if(val<=0)

stat = ADD;

strip.show();

delay(5);

if(stat==SUB) val --;

else if(stat==ADD) val++;

}

• 參考資料

• http://cheng-min-i-taiwan.blogspot.tw/2016/01/adafruit-neopixel.html

• http://www.html5in.com/cloud-connected-neopixels-using-the-particle-core/