https://qiita.com/loveandsheep/items/e1295ec9ce589eaa85c9?utm_campaign=popular_items&utm_medium=feed&utm_source=popular_items

DMX512_receive.ino

#include "DMXSerial.h"

int startCh = 0;//DMXのスタートアドレス

void setup()
{
  DMXSerial.init(DMXReceiver);
  pinMode(13, OUTPUT);
}

void loop()
{
  unsigned long lastPacket = DMXSerial.noDataSince();

  if (lastPacket < 5000) {
      byte dmx[4];
      for (int i = 0;i < 4;i++)
        dmx[i] = DMXSerial.read(startCh + i);
      if(dmx[1] >= 127){
        digitalWrite(13, HIGH);
      }else{
        digitalWrite(13, LOW);
      }
  }
}