DMX USB, FastLED RGB LED stripe, OP-Z

dmx.ino

#include <SoftwareSerial.h>
#include "DMXUSB.h"
#include <FastLED.h>

SoftwareSerial mySerial(10, 11); // RX, TX


#define LED_PIN LED_BUILTIN
#define DMXUSB_BAUDRATE 115200
#define NUM_LEDS 16
#define DATA_PIN 3
CRGB leds[NUM_LEDS];

void myDMXCallback(int universe, char buffer[512]) {
  // Serial.println("msg");
  // Serial.println(universe);

  digitalWrite(LED_PIN, LOW);
  leds[0] = CRGB::Black;

  for (int index = 0; index < 512; index++) {
    int value = buffer[index]; // DMX value 0 to 255

    if (value != 0) {
      // Serial.print(index);
      // Serial.print("=");
      // Serial.println(value);
    }

    int LEDchannel = index; // Find the LED number; can't fit a 3-channel fixture on the remaining two channels
    if (LEDchannel <= (NUM_LEDS * 3) - 1) { // If DMX channel (LEDchannel starts at 0) is in range of LEDs (3 channels per LED for RGB)
      int colorChannel = LEDchannel % 3; // Find the color channel of the LED addressed
      int ledID = (LEDchannel - colorChannel) / 3; // Find the FastLED index of the LED addressed
      if (colorChannel == 2) leds[ledID].r = value / 30; // If the channel is red, write the red value of the LED
      if (colorChannel == 1) leds[ledID].g = value / 30; // If the channel is green, write the red value of the LED
      if (colorChannel == 0) leds[ledID].b = value / 30; // If the channel is blue, write the blue value of the LED
    }

    if (universe == 0 && index < 3 && value != 0) {
      digitalWrite(LED_PIN, HIGH);
    }

  }

  FastLED.show(); // Display the frame after processing all channels

}

DMXUSB myDMXUsb(mySerial, DMXUSB_BAUDRATE, 0, myDMXCallback);

void setup() {
  //Serial.begin(115200);
  mySerial.begin(DMXUSB_BAUDRATE);
  FastLED.addLeds<NEOPIXEL, DATA_PIN>(leds, NUM_LEDS); // todo wrong colors?

  pinMode(LED_PIN, OUTPUT);
  digitalWrite(LED_PIN, HIGH); delay(100); digitalWrite(LED_PIN, LOW); delay(100);
  digitalWrite(LED_PIN, HIGH); delay(100); digitalWrite(LED_PIN, LOW); delay(100);
  leds[0] = CRGB::Red;  FastLED.show(); delay(100); leds[0] = CRGB::Black; FastLED.show();

}

void loop() {

  myDMXUsb.listen();
}