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#include <I2Cdev.h>

#include <LiquidCrystal.h>

#include "MPU6050_6Axis_MotionApps20.h"

#if I2CDEV_IMPLEMENTATION == I2CDEV_ARDUINO_WIRE
    #include "Wire.h"
#endif

// 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;
//MPU6050 mpu(0x69); // <-- use for AD0 high

/* =========================================================================
   NOTE: In addition to connection 3.3v, GND, SDA, and SCL, this sketch
   depends on the MPU-6050's INT pin being connected to the Arduino's
   external interrupt #0 pin. On the Arduino Uno and Mega 2560, this is
   digital I/O pin 2.
 * ========================================================================= */


// uncomment "OUTPUT_READABLE_REALACCEL" if you want to see acceleration
// components with gravity removed. This acceleration reference frame is
// not compensated for orientation, so +X is always +X according to the
// sensor, just without the effects of gravity. If you want acceleration
// compensated for orientation, us OUTPUT_READABLE_WORLDACCEL instead.
#define OUTPUT_READABLE_REALACCEL

// uncomment "OUTPUT_READABLE_WORLDACCEL" if you want to see acceleration
// components with gravity removed and adjusted for the world frame of
// reference (yaw is relative to initial orientation, since no magnetometer
// is present in this case). Could be quite handy in some cases.
//#define OUTPUT_READABLE_WORLDACCEL


#define LED_PIN 13 // (Arduino is 13, Teensy is 11, Teensy++ is 6)
bool blinkState = false;

// 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

volatile bool mpuInterrupt = false;     // indicates whether MPU interrupt pin has gone high
void dmpDataReady() {
    mpuInterrupt = true;
}

LiquidCrystal lcd(12,11,5,4,3,7);

void setup() {
    lcd.begin(16,2);
    lcd.setCursor(0,0);
    lcd.print(F("MPU-6050"));
    // join I2C bus (I2Cdev library doesn't do this automatically)
    #if I2CDEV_IMPLEMENTATION == I2CDEV_ARDUINO_WIRE
        Wire.begin();
        TWBR = 24; // 400kHz I2C clock (200kHz if CPU is 8MHz)
    #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);

    // NOTE: 8MHz or slower host processors, like the Teensy @ 3.3v or Ardunio
    // 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
    lcd.clear();
    lcd.print(F("Initializing I2C devices..."));
    mpu.initialize();
    lcd.clear();
    
    lcd.print(F("MPU initialized"));

    // verify connection
    lcd.print(F("Testing device connections..."));
    lcd.print(mpu.testConnection() ? F("MPU6050 connection successful") : F("MPU6050 connection failed"));

    // load and configure the DMP
    lcd.print(F("Initializing DMP..."));
    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
        lcd.print(F("Enabling DMP..."));
        mpu.setDMPEnabled(true);

        // set our DMP Ready flag so the main loop() function knows it's okay to use it
        lcd.print(F("DMP ready! Waiting for first interrupt..."));
        
        // enable Arduino interrupt detection
        lcd.print(F("Enabling interrupt detection (Arduino external interrupt 0)..."));
        attachInterrupt(0, dmpDataReady, RISING);
        mpuIntStatus = mpu.getIntStatus();
        dmpReady = true;

        // get expected DMP packet size for later comparison
        packetSize = mpu.dmpGetFIFOPacketSize();
        
    } else {
        // ERROR!
        // 1 = initial memory load failed
        // 2 = DMP configuration updates failed
        // (if it's going to break, usually the code will be 1)
        lcd.print(F("DMP Initialization failed (code "));
        lcd.print(devStatus);
        lcd.print(F(")"));
    }
    
    // configure LED for output
    pinMode(LED_PIN, OUTPUT);
    lcd.clear();
    int wait = 3;
    for (int i = wait; i > 0; --i) {
      lcd.clear();
      lcd.printf("Waiting for %d", i);
      delay(1000);
    }
    lcd.clear();
    lcd.print("Go!");
}

int16_t maxZ = 0;
int16_t prevZ = 0;
int threshold = 500;

long startTime = 0;
long stopTime = 0;

boolean stopped = true;
boolean ended = false;

void loop() {
    // if programming failed, don't try to do anything
    if (!dmpReady || ended) return;
    
    // 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();
        //lcd.print(F("FIFO overflow!"));
    // 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();
      mpu.getFIFOBytes(fifoBuffer, packetSize);
      fifoCount -= packetSize;
      
      // calculate real acceleration, adjusted to remove gravity
      mpu.dmpGetQuaternion(&q, fifoBuffer);
      mpu.dmpGetAccel(&aa, fifoBuffer);
      mpu.dmpGetGravity(&gravity, &q);
      mpu.dmpGetLinearAccel(&aaReal, &aa, &gravity);
      
      maxZ = max(maxZ,abs(aaReal.z));
      
      int16_t deltaZ = abs(aaReal.z) - prevZ;
      prevZ = abs(aaReal.z);
      if (stopped && !ended) {
        // stopped so start recording
        if (deltaZ > threshold) {
          stopped = false;
          startTime = millis();
          lcd.setCursor(0,0);
          lcd.print("Recording...");
        }
      } else {
        if (deltaZ == 0 && maxZ != 0) {
          stopped = true;
          stopTime = millis();
          ended = true; 
        }
      }
      
      if (ended) {
        ended = true;
        long elapsedTime = stopTime - startTime;
        lcd.clear();
        lcd.printf("MaxAccel = %d", abs(maxZ));  
        //Serial.printf("MaxAccel = %d\n", abs(maxZ));
        lcd.setCursor(0,1); // second line       
        lcd.printf("ET %dms", elapsedTime);
        //Serial.printf("ET %dms\n", elapsedTime);
      }
    }
}