Modify version described in the coment in https://www.instructables.com/LEDs-and-Gravity-/ project

Balancing_LED_using_MPU6050gyro.ino

/**********************************************************************************************************************
  Copyright (c) 2017 Roel Arits

  Permission is hereby granted, free of charge, to any person obtaining a copy
  of this software and associated documentation files (the "Software"), to deal
  in the Software without restriction, including without limitation the rights
  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  copies of the Software, and to permit persons to whom the Software is
  furnished to do so, subject to the following conditions:

  The above copyright notice and this permission notice shall be included in
  all copies or substantial portions of the Software.

  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  THE SOFTWARE.
 **********************************************************************************************************************/
 
 /**********************************************************************************************************************
   Modify by derfaq 02/21/21 for configuartion described in the coment in https://www.instructables.com/LEDs-and-Gravity-/
 **********************************************************************************************************************/
 
// I2C device class (I2Cdev) demonstration Arduino sketch for MPU6050 class using DMP (MotionApps v2.0)
// 6/21/2012 by Jeff Rowberg <[email protected]>
// Updates should (hopefully) always be available at https://github.com/jrowberg/i2cdevlib
//
// Changelog:
//      2013-05-08 - added seamless Fastwire support
//                 - added note about gyro calibration
//      2012-06-21 - added note about Arduino 1.0.1 + Leonardo compatibility error
//      2012-06-20 - improved FIFO overflow handling and simplified read process
//      2012-06-19 - completely rearranged DMP initialization code and simplification
//      2012-06-13 - pull gyro and accel data from FIFO packet instead of reading directly
//      2012-06-09 - fix broken FIFO read sequence and change interrupt detection to RISING
//      2012-06-05 - add gravity-compensated initial reference frame acceleration output
//                 - add 3D math helper file to DMP6 example sketch
//                 - add Euler output and Yaw/Pitch/Roll output formats
//      2012-06-04 - remove accel offset clearing for better results (thanks Sungon Lee)
//      2012-06-01 - fixed gyro sensitivity to be 2000 deg/sec instead of 250
//      2012-05-30 - basic DMP initialization working

/* ============================================
I2Cdev device library code is placed under the MIT license
Copyright (c) 2012 Jeff Rowberg

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
===============================================
*/

#include <Adafruit_NeoPixel.h>

// ======================= LED MOTION ====================================
#include "LEDMotion.h"

// ======================= MPU6050 ====================================
#include "I2Cdev.h"
#include "MPU6050_6Axis_MotionApps20.h"
// Arduino Wire library is required if I2Cdev I2CDEV_ARDUINO_WIRE implementation
// is used in I2Cdev.h
#if I2CDEV_IMPLEMENTATION == I2CDEV_ARDUINO_WIRE
    #include "Wire.h"
#endif

//#define OUTPUT_READABLE_QUATERNION
//#define OUTPUT_READABLE_EULER
#define OUTPUT_READABLE_YAWPITCHROLL
//#define OUTPUT_READABLE_REALACCEL
//#define OUTPUT_READABLE_WORLDACCEL

#define INTERRUPT_PIN     2  // use pin 2 on Arduino Uno & most boards

// ======================= NEOPIXEL ====================================
#define PIN               6
#define NUM_LEDS          8

// Parameter 1 = number of pixels in strip
// Parameter 2 = 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)

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

// ====================================================================
// MPU control/status vars
bool        dmpReady = false;  // set true if DMP init was successful
uint8_t     mpuIntStatus;   // holds actual interrupt status byte from MPU
uint8_t     devStatus;      // return status after each device operation (0 = success, !0 = error)
uint16_t    packetSize;    // expected DMP packet size (default is 42 bytes)
uint16_t    fifoCount;     // count of all bytes currently in FIFO
uint8_t     fifoBuffer[64]; // FIFO storage buffer

// orientation/motion vars
Quaternion q;           // [w, x, y, z]         quaternion container
VectorInt16 aa;         // [x, y, z]            accel sensor measurements
VectorInt16 aaReal;     // [x, y, z]            gravity-free accel sensor measurements
VectorInt16 aaWorld;    // [x, y, z]            world-frame accel sensor measurements
VectorFloat gravity;    // [x, y, z]            gravity vector
float euler[3];         // [psi, theta, phi]    Euler angle container
float ypr[3];           // [yaw, pitch, roll]   yaw/pitch/roll container and gravity vector

// ====================================================================
TLEDMotion LEDMotion;

// class default I2C address is 0x68
// specific I2C addresses may be passed as a parameter here
// AD0 low = 0x68 (default for SparkFun breakout and InvenSense evaluation board)
// AD0 high = 0x69
MPU6050     mpu;

// ================================================================
// ===               INTERRUPT DETECTION ROUTINE                ===
// ================================================================

volatile bool mpuInterrupt = false;     // indicates whether MPU interrupt pin has gone high

void dmpDataReady() 
{
    mpuInterrupt = true;
}

//---------------------------------------------------------------------------------------
// Initialisation
//---------------------------------------------------------------------------------------
void setup() 
{
  pinMode( 3 , OUTPUT );
  digitalWrite( 3 , HIGH );
  
  // Init random generator
  randomSeed(analogRead(0));
  
  // Init neopixel strip
  strip.begin();
  strip.show();

  LEDMotion.PrepareStart(&strip);

  // Debug
  #if  ((MOTION_DEBUG == MOTION_DEBUG_ALL) || (MOTION_DEBUG == MOTION_DEBUG_MOTION) || (MOTION_DEBUG == MOTION_DEBUG_STATES))
  // Init serial port for debugging
  Serial.begin(115200);
  // wait for serial port to connect. Needed for native USB
  while (!Serial) {};
  Serial.print("Serial port ready");
  #endif

  // Init accelation/gyro sensor
  MPU6050Init();
}

//---------------------------------------------------------------------------------------
// Main loop
//---------------------------------------------------------------------------------------
void loop() 
{
  // Convert the yawn, pitch and roll from radians to an angle in degrees
  float yawn  = (ypr[0] * 180.0)/M_PI;
  float pitch = (ypr[1] * 180.0)/M_PI;
  float roll  = (ypr[2] * 180.0)/M_PI;
  
  // Main stste machine for LED motion
  LEDMotion.Main(&strip, yawn, pitch, roll);

  // Main for accelation/gyro sensor
  MPU6050Main();
}  

//---------------------------------------------------------------------------------------
// Init MPU6050 driver
//---------------------------------------------------------------------------------------
void MPU6050Init(void)
{
  // join I2C bus (I2Cdev library doesn't do this automatically)
  #if I2CDEV_IMPLEMENTATION == I2CDEV_ARDUINO_WIRE
      Wire.begin();
      Wire.setClock(400000); // 400kHz I2C clock. Comment this line if having compilation difficulties
  #elif I2CDEV_IMPLEMENTATION == I2CDEV_BUILTIN_FASTWIRE
      Fastwire::setup(400, true);
  #endif

  // initialize serial communication
  // (115200 chosen because it is required for Teapot Demo output, but it's
  // really up to you depending on your project)
  //Serial.begin(115200);
  //while (!Serial); // wait for Leonardo enumeration, others continue immediately

  // NOTE: 8MHz or slower host processors, like the Teensy @ 3.3V or Arduino
  // Pro Mini running at 3.3V, cannot handle this baud rate reliably due to
  // the baud timing being too misaligned with processor ticks. You must use
  // 38400 or slower in these cases, or use some kind of external separate
  // crystal solution for the UART timer.

  // initialize device
  #if  (MOTION_DEBUG == MOTION_DEBUG_ALL)
  Serial.println(F("Initializing I2C devices..."));
  #endif
  
  mpu.initialize();
  pinMode(INTERRUPT_PIN, INPUT);

  #if  (MOTION_DEBUG == MOTION_DEBUG_ALL)
  // verify connection
  Serial.println(F("Testing device connections..."));
  Serial.println(mpu.testConnection() ? F("MPU6050 connection successful") : F("MPU6050 connection failed"));
  #endif
  
  // wait for ready
  //Serial.println(F("\nSend any character to begin DMP programming and demo: "));
  //while (Serial.available() && Serial.read()); // empty buffer
  //while (!Serial.available());                 // wait for data
  //while (Serial.available() && Serial.read()); // empty buffer again

  // load and configure the DMP
  #if  (MOTION_DEBUG == MOTION_DEBUG_ALL)
  Serial.println(F("Initializing DMP..."));
  #endif
  
  devStatus = mpu.dmpInitialize();

  // supply your own gyro offsets here, scaled for min sensitivity
  //mpu.setXGyroOffset(220);
  //mpu.setYGyroOffset(76);
  //mpu.setZGyroOffset(-85);
  //mpu.setZAccelOffset(1788); // 1688 factory default for my test chip

  // make sure it worked (returns 0 if so)
  if (devStatus == 0) 
  {
      // turn on the DMP, now that it's ready
      #if  (MOTION_DEBUG == MOTION_DEBUG_ALL)
      Serial.println(F("Enabling DMP..."));
      #endif
      
      mpu.setDMPEnabled(true);

      #if  (MOTION_DEBUG == MOTION_DEBUG_ALL)
      // enable Arduino interrupt detection
      Serial.println(F("Enabling interrupt detection (Arduino external interrupt 0)..."));
      #endif
      attachInterrupt(digitalPinToInterrupt(INTERRUPT_PIN), dmpDataReady, RISING);
      mpuIntStatus = mpu.getIntStatus();

      // set our DMP Ready flag so the main loop() function knows it's okay to use it
      #if  (MOTION_DEBUG == MOTION_DEBUG_ALL)
      Serial.println(F("DMP ready! Waiting for first interrupt..."));
      #endif
      dmpReady = true;

      // get expected DMP packet size for later comparison
      packetSize = mpu.dmpGetFIFOPacketSize();
  } 
  else 
  {
      #if  (MOTION_DEBUG == MOTION_DEBUG_ALL)
      // ERROR!
      // 1 = initial memory load failed
      // 2 = DMP configuration updates failed
      // (if it's going to break, usually the code will be 1)
      Serial.print(F("DMP Initialization failed (code "));
      Serial.print(devStatus);
      Serial.println(F(")"));
      #endif
  }
}

//---------------------------------------------------------------------------------------
// MPU6050 main loop code
//---------------------------------------------------------------------------------------
void MPU6050Main(void)
{
  // if programming failed, don't try to do anything
  if (!dmpReady) 
    return;
  /*
  // wait for MPU interrupt or extra packet(s) available
  while (!mpuInterrupt && fifoCount < packetSize) 
  {
      // other program behavior stuff here
      // .
      // .
      // .
      // if you are really paranoid you can frequently test in between other
      // stuff to see if mpuInterrupt is true, and if so, "break;" from the
      // while() loop to immediately process the MPU data
      // .
      // .
      // .
  }
  */
  
  if (mpuInterrupt || fifoCount > packetSize)
  {
    // reset interrupt flag and get INT_STATUS byte
    mpuInterrupt = false;
    mpuIntStatus = mpu.getIntStatus();

    // get current FIFO count
    fifoCount = mpu.getFIFOCount();

    // check for overflow (this should never happen unless our code is too inefficient)
    if ((mpuIntStatus & 0x10) || fifoCount == 1024) 
    {
        // reset so we can continue cleanly
        mpu.resetFIFO();
        
        #if  (MOTION_DEBUG == MOTION_DEBUG_ALL)
        Serial.println(F("FIFO overflow!"));
        #endif
          
    // otherwise, check for DMP data ready interrupt (this should happen frequently)
    } 
    else if (mpuIntStatus & 0x02) 
    {
        // wait for correct available data length, should be a VERY short wait
        while (fifoCount < packetSize) 
          fifoCount = mpu.getFIFOCount();

        // read a packet from FIFO
        mpu.getFIFOBytes(fifoBuffer, packetSize);
        
        // track FIFO count here in case there is > 1 packet available
        // (this lets us immediately read more without waiting for an interrupt)
        fifoCount -= packetSize;

         #ifdef OUTPUT_READABLE_QUATERNION
            // display quaternion values in easy matrix form: w x y z
            mpu.dmpGetQuaternion(&q, fifoBuffer);
            #if  (MOTION_DEBUG == MOTION_DEBUG_ALL)
            Serial.print("quat\t");
            Serial.print(q.w);
            Serial.print("\t");
            Serial.print(q.x);
            Serial.print("\t");
            Serial.print(q.y);
            Serial.print("\t");
            Serial.println(q.z);
            #endif
        #endif

        #ifdef OUTPUT_READABLE_EULER
            // display Euler angles in degrees
            mpu.dmpGetQuaternion(&q, fifoBuffer);
            mpu.dmpGetEuler(euler, &q);
            #if  (MOTION_DEBUG == MOTION_DEBUG_ALL)
            Serial.print("euler\t");
            Serial.print(euler[0] * 180/M_PI);
            Serial.print("\t");
            Serial.print(euler[1] * 180/M_PI);
            Serial.print("\t");
            Serial.println(euler[2] * 180/M_PI);
            #endif
        #endif
        
        #ifdef OUTPUT_READABLE_YAWPITCHROLL
            // display Euler angles in degrees
            mpu.dmpGetQuaternion(&q, fifoBuffer);
            mpu.dmpGetGravity(&gravity, &q);
            mpu.dmpGetYawPitchRoll(ypr, &q, &gravity);
            #if  (MOTION_DEBUG == MOTION_DEBUG_ALL)
            Serial.print("ypr\t");
            Serial.print(ypr[0] * 180/M_PI);
            Serial.print("\t");
            Serial.print(ypr[1] * 180/M_PI);
            Serial.print("\t");
            Serial.println(ypr[2] * 180/M_PI);
            #endif
        #endif
        
        #ifdef OUTPUT_READABLE_REALACCEL
            // display real acceleration, adjusted to remove gravity
            mpu.dmpGetQuaternion(&q, fifoBuffer);
            mpu.dmpGetAccel(&aa, fifoBuffer);
            mpu.dmpGetGravity(&gravity, &q);
            mpu.dmpGetLinearAccel(&aaReal, &aa, &gravity);
            #if  (MOTION_DEBUG == MOTION_DEBUG_ALL)
            Serial.print("areal\t");
            Serial.print(aaReal.x);
            Serial.print("\t");
            Serial.print(aaReal.y);
            Serial.print("\t");
            Serial.println(aaReal.z);
            #endif
        #endif

        #ifdef OUTPUT_READABLE_WORLDACCEL
            // display initial world-frame acceleration, adjusted to remove gravity
            // and rotated based on known orientation from quaternion
            mpu.dmpGetQuaternion(&q, fifoBuffer);
            mpu.dmpGetAccel(&aa, fifoBuffer);
            mpu.dmpGetGravity(&gravity, &q);
            mpu.dmpGetLinearAccel(&aaReal, &aa, &gravity);
            mpu.dmpGetLinearAccelInWorld(&aaWorld, &aaReal, &q);
            #if  (MOTION_DEBUG == MOTION_DEBUG_ALL)
            Serial.print("aworld\t");
            Serial.print(aaWorld.x);
            Serial.print("\t");
            Serial.print(aaWorld.y);
            Serial.print("\t");
            Serial.println(aaWorld.z);
            #endif
        #endif
    
        #ifdef OUTPUT_TEAPOT
            // display quaternion values in InvenSense Teapot demo format:
            teapotPacket[2] = fifoBuffer[0];
            teapotPacket[3] = fifoBuffer[1];
            teapotPacket[4] = fifoBuffer[4];
            teapotPacket[5] = fifoBuffer[5];
            teapotPacket[6] = fifoBuffer[8];
            teapotPacket[7] = fifoBuffer[9];
            teapotPacket[8] = fifoBuffer[12];
            teapotPacket[9] = fifoBuffer[13];
            #if  (MOTION_DEBUG == MOTION_DEBUG_ALL)
            Serial.write(teapotPacket, 14);
            #endif
            teapotPacket[11]++; // packetCount, loops at 0xFF on purpose
        #endif
    }
  }
}