sinelon_pixels

/* sinelon_pixels 
 *  
 *  Moves a single sine wave back and forth (or continuously) using waves.
 *  
 *  
 * By: Andrew Tuline
 *
 * Date: January 2019
 *
 * This uses the built in FastLED beatsin8 combined with a sinewave to move one or more pixels back and forth.
 * 
 * The challenge is scaling low brightness pixels as they still look pretty bright. That's a whole other ballgame.
 * 
 */


#include "FastLED.h"                                          // FastLED library. Preferably the latest copy of FastLED 2.1.

#if FASTLED_VERSION < 3001000
#error "Requires FastLED 3.1 or later; check github for latest code."
#endif 

// Fixed definitions cannot change on the fly.
#define LED_DT 12                                             // Data pin to connect to the strip.
#define LED_CK 11                                             // Clock pin for WS2801 or APA102.
#define COLOR_ORDER BGR                                       // It's GRB for WS2812 and BGR for APA102.
#define LED_TYPE APA102                                       // Using APA102, WS2812, WS2801. Don't forget to modify LEDS.addLeds to suit.
#define NUM_LEDS 40                                           // Number of LED's.

// Global variables can be changed on the fly.
uint8_t max_bright = 128;                                      // Overall brightness definition. It can be changed on the fly.

struct CRGB leds[NUM_LEDS];                                    // Initialize our LED array.
CRGBPalette16 currentPalette;


void setup() {
  
  Serial.begin(57600);                                        // Initialize serial port for debugging.
  delay(1000);

//  LEDS.addLeds<LED_TYPE, LED_DT, COLOR_ORDER>(leds, NUM_LEDS);        // Use this for WS2812B
  LEDS.addLeds<LED_TYPE, LED_DT, LED_CK, COLOR_ORDER>(leds, NUM_LEDS);  // Use this for WS2801 or APA102

  currentPalette = PartyColors_p;
  
  FastLED.setBrightness(max_bright);
  set_max_power_in_volts_and_milliamps(5, 500);                     // FastLED Power management set at 5V, 500mA.
  
} // setup()



void loop () {

  EVERY_N_MILLISECONDS(20) {                                        // FastLED based non-blocking delay to update/display the sequence.
    sinelon_pixels();                                               // You don't really need the EVERY_N_MILLISECONDS in this routine.
  }

  FastLED.show();

} // loop()



void sinelon_pixels() {

  fadeToBlackBy( leds, NUM_LEDS, 220);
  
//  int pos1 = millis()/64;                              // Continuous loop.
  int pos1 =  beatsin8(10,0,NUM_LEDS-7);                 // Back and forth a la sinelon.

  for (uint8_t i = 0; i<7; i++) {
    int thisbright = cubicwave8((i*40));                // Could've used another sine function and adjusted the phase to suit.
    thisbright = thisbright*thisbright/255;             // Increase the brightness drop (see gamma correction).
    leds[(i+pos1)%NUM_LEDS] = ColorFromPalette( currentPalette, 5, thisbright, LINEARBLEND);    
  }
  
} // sinelon_pixels()