Плата в виде кольца с 16 RGB светодиодами WS2812. Каждый светодиод имеет встроенный ШИМ-контроллер и схему адресации, позволяющую, управлять каждым отдельным светодиодом в схеме независимо от остальных. Управление происходит по однопроводной последовательной шине.
Алгоритм управления линейкой NeoPixel WS2812 очень прост: первый светодиод принимает и записывает в свою внутреннюю память первые 24 бита с информацией о яркости каждого из трех встроенных в него диодов, а все остальные биты последовательности передает второму светодиоду. Соответственно второй светодиод получит и обработает свои 24 бита, а оставшуюся часть исходного сигнала передаст третьему и т.д. После передачи данных для всех светодиодов необходимо сделать паузу длиной 50 мкс, чтобы состояние светодиодов обновилось.
Для генерации управляющего сигнала может пригодиться микроконтроллер или плата Arduino.
Пример
GND > GND
5V > 5V
D6 > DIN (между ними резистор 200 – 500 Ом)
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// A basic everyday NeoPixel strip test program. // NEOPIXEL BEST PRACTICES for most reliable operation: // - Add 1000 uF CAPACITOR between NeoPixel strip's + and - connections. // - MINIMIZE WIRING LENGTH between microcontroller board and first pixel. // - NeoPixel strip's DATA-IN should pass through a 300-500 OHM RESISTOR. // - AVOID connecting NeoPixels on a LIVE CIRCUIT. If you must, ALWAYS // connect GROUND (-) first, then +, then data. // - When using a 3.3V microcontroller with a 5V-powered NeoPixel strip, // a LOGIC-LEVEL CONVERTER on the data line is STRONGLY RECOMMENDED. // (Skipping these may work OK on your workbench but can fail in the field) #include <Adafruit_NeoPixel.h> #ifdef __AVR__ #include <avr/power.h> // Required for 16 MHz Adafruit Trinket #endif // Which pin on the Arduino is connected to the NeoPixels? // On a Trinket or Gemma we suggest changing this to 1: #define LED_PIN 6 // How many NeoPixels are attached to the Arduino? #define LED_COUNT 16 // Declare our NeoPixel strip object: Adafruit_NeoPixel strip(LED_COUNT, LED_PIN, NEO_GRB + NEO_KHZ800); // Argument 1 = Number of pixels in NeoPixel strip // Argument 2 = Arduino pin number (most are valid) // Argument 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) // setup() function -- runs once at startup -------------------------------- void setup() { // These lines are specifically to support the Adafruit Trinket 5V 16 MHz. // Any other board, you can remove this part (but no harm leaving it): #if defined(__AVR_ATtiny85__) && (F_CPU == 16000000) clock_prescale_set(clock_div_1); #endif // END of Trinket-specific code. strip.begin(); // INITIALIZE NeoPixel strip object (REQUIRED) strip.show(); // Turn OFF all pixels ASAP strip.setBrightness(50); // Set BRIGHTNESS to about 1/5 (max = 255) } // loop() function -- runs repeatedly as long as board is on --------------- void loop() { // Fill along the length of the strip in various colors... colorWipe(strip.Color(255, 0, 0), 50); // Red colorWipe(strip.Color( 0, 255, 0), 50); // Green colorWipe(strip.Color( 0, 0, 255), 50); // Blue // Do a theater marquee effect in various colors... theaterChase(strip.Color(127, 127, 127), 50); // White, half brightness theaterChase(strip.Color(127, 0, 0), 50); // Red, half brightness theaterChase(strip.Color( 0, 0, 127), 50); // Blue, half brightness rainbow(10); // Flowing rainbow cycle along the whole strip theaterChaseRainbow(50); // Rainbow-enhanced theaterChase variant } // Some functions of our own for creating animated effects ----------------- // Fill strip pixels one after another with a color. Strip is NOT cleared // first; anything there will be covered pixel by pixel. Pass in color // (as a single 'packed' 32-bit value, which you can get by calling // strip.Color(red, green, blue) as shown in the loop() function above), // and a delay time (in milliseconds) between pixels. void colorWipe(uint32_t color, int wait) { for(int i=0; i<strip.numPixels(); i++) { // For each pixel in strip... strip.setPixelColor(i, color); // Set pixel's color (in RAM) strip.show(); // Update strip to match delay(wait); // Pause for a moment } } // Theater-marquee-style chasing lights. Pass in a color (32-bit value, // a la strip.Color(r,g,b) as mentioned above), and a delay time (in ms) // between frames. void theaterChase(uint32_t color, int wait) { for(int a=0; a<10; a++) { // Repeat 10 times... for(int b=0; b<3; b++) { // 'b' counts from 0 to 2... strip.clear(); // Set all pixels in RAM to 0 (off) // 'c' counts up from 'b' to end of strip in steps of 3... for(int c=b; c<strip.numPixels(); c += 3) { strip.setPixelColor(c, color); // Set pixel 'c' to value 'color' } strip.show(); // Update strip with new contents delay(wait); // Pause for a moment } } } // Rainbow cycle along whole strip. Pass delay time (in ms) between frames. void rainbow(int wait) { // Hue of first pixel runs 5 complete loops through the color wheel. // Color wheel has a range of 65536 but it's OK if we roll over, so // just count from 0 to 5*65536. Adding 256 to firstPixelHue each time // means we'll make 5*65536/256 = 1280 passes through this outer loop: for(long firstPixelHue = 0; firstPixelHue < 5*65536; firstPixelHue += 256) { for(int i=0; i<strip.numPixels(); i++) { // For each pixel in strip... // Offset pixel hue by an amount to make one full revolution of the // color wheel (range of 65536) along the length of the strip // (strip.numPixels() steps): int pixelHue = firstPixelHue + (i * 65536L / strip.numPixels()); // strip.ColorHSV() can take 1 or 3 arguments: a hue (0 to 65535) or // optionally add saturation and value (brightness) (each 0 to 255). // Here we're using just the single-argument hue variant. The result // is passed through strip.gamma32() to provide 'truer' colors // before assigning to each pixel: strip.setPixelColor(i, strip.gamma32(strip.ColorHSV(pixelHue))); } strip.show(); // Update strip with new contents delay(wait); // Pause for a moment } } // Rainbow-enhanced theater marquee. Pass delay time (in ms) between frames. void theaterChaseRainbow(int wait) { int firstPixelHue = 0; // First pixel starts at red (hue 0) for(int a=0; a<30; a++) { // Repeat 30 times... for(int b=0; b<3; b++) { // 'b' counts from 0 to 2... strip.clear(); // Set all pixels in RAM to 0 (off) // 'c' counts up from 'b' to end of strip in increments of 3... for(int c=b; c<strip.numPixels(); c += 3) { // hue of pixel 'c' is offset by an amount to make one full // revolution of the color wheel (range 65536) along the length // of the strip (strip.numPixels() steps): int hue = firstPixelHue + c * 65536L / strip.numPixels(); uint32_t color = strip.gamma32(strip.ColorHSV(hue)); // hue -> RGB strip.setPixelColor(c, color); // Set pixel 'c' to value 'color' } strip.show(); // Update strip with new contents delay(wait); // Pause for a moment firstPixelHue += 65536 / 90; // One cycle of color wheel over 90 frames } } } |
Библиотека Adafruit NeoPixel
Документация WS2812B
