Electronic Tape Measure [IMU + Rotary Encoder + BLE + GUI]

This is a very simple and basic tool that helps in measuring distance [using a rotary encoder ] and also knows the heading reference/orientation via an IMU sensor[MPU-6050].

So that's it.

Further Scope

For now, our devices only measure 2D space, but we can use them to measure 3D space [the last thing humanity needs to be done is measure 3D space using this tool ]

But some major development that can be added or contributed(🥲) are :

• Restructuring the control flow in the main.py[software side]
• Changes in many/every function.
• Not using the software in the first place [it was built so that we feel we did something], displaying all the metrics in a separate display[I2C]/the hardware itself.
• Adding a pointer/sight/reference to help the user holding it know where to start and stop.
• Using a better IMU Sensor, we are using MPU6050 on top with DMP, so there is a significant yaw drift[we had only one thing to do 😔].
• Using a hall effect sensor, instead of a rotary encoder[we just went with the flow, although we knew it was coming].
• Angle interchangeablity.
• Closing the project and not working on stupid ideas, [but it can be efficient if made in a very small form factor

Still It Gets the Job Done 🔥 :

Although it has some limitations, it does work and works fine.

It gives the following output to the user:

• Distance
• Displacement
• Area
• X and Y axis Displacement

Although, it is very easy after we get the two points[start and end]

Demo Video 📺

Compensator Testing:

Circuit

The First Prototype Consists of :

• Arduino Pro Micro
• Bluetooth HC-05
• Rotary Encoder
• MPU-6050

Schematics:

Current Build [🙈🙉🙊]

GUI Code [Python]:

import bluetooth 
import socket
import struct
import sys
from PyQt5.QtWidgets import QApplication, QWidget, QComboBox, QLabel,QFileDialog, QVBoxLayout, QHBoxLayout, QPushButton,QFrame,QDoubleSpinBox
from PyQt5.QtCore import Qt, QThread, pyqtSignal,QPoint, QLineF, QPointF
from PyQt5.QtGui import QPainter, QColor, QPen,QPolygon,QPainterPath
from PyQt5.QtOpenGL import QGLWidget 
import OpenGL.GL as gl        # python wrapping of OpenGL
from OpenGL import GLU 
import math
import ctypes
import json
from OpenGL.arrays import vbo
import numpy as np

x_pos = 0
y_pos = 0
r_value = 0
y_value = 0
rot_const=0
comp_mode=False
x=0.0
y=0.0
z=0.0

class GLWidget(QGLWidget):
    def __init__(self, parent=None):
        QGLWidget.__init__(self, parent)
            
    def initializeGL(self):
        self.qglClearColor(QColor(0, 0, 0))    # initialize the screen to blue
        gl.glEnable(gl.GL_DEPTH_TEST)                  # enable depth testing
        self.initGeometry()
        self.rotX = 0.0
        self.rotY = 0.0
        self.rotZ = 0.0
         
    def resizeGL(self, width, height):
        gl.glViewport(0, 0, width, height)
        gl.glMatrixMode(gl.GL_PROJECTION)
        gl.glLoadIdentity()
        aspect = width / float(height)

        GLU.gluPerspective(45.0, aspect, 1.0, 100.0)
        gl.glMatrixMode(gl.GL_MODELVIEW)

    def paintGL(self):
        gl.glClear(gl.GL_COLOR_BUFFER_BIT | gl.GL_DEPTH_BUFFER_BIT)

        gl.glPushMatrix()    # push the current matrix to the current stack

        gl.glTranslate(0.0, 0.0, -50.0)    # third, translate cube to specified depth
        gl.glScale(20.0, 20.0, 20.0)       # second, scale cube
        gl.glRotate(self.rotX, 1.0, 0.0, 0.0)
        gl.glRotate(self.rotY, 0.0, 1.0, 0.0)
        gl.glRotate(self.rotZ, 0.0, 0.0, 1.0)
        gl.glTranslate(-0.5, -0.5, -0.5)   # first, translate cube center to origin

        gl.glEnableClientState(gl.GL_VERTEX_ARRAY)
        gl.glEnableClientState(gl.GL_COLOR_ARRAY)

        gl.glVertexPointer(3, gl.GL_FLOAT, 0, self.vertVBO)
        gl.glColorPointer(3, gl.GL_FLOAT, 0, self.colorVBO)

        gl.glDrawElements(gl.GL_LINES, len(self.cubeIdxArray), gl.GL_UNSIGNED_INT, self.cubeIdxArray)

        gl.glDisableClientState(gl.GL_VERTEX_ARRAY)
        gl.glDisableClientState(gl.GL_COLOR_ARRAY)

        gl.glPopMatrix()    # restore the previous modelview matrix
        
    def initGeometry(self):
        vertices = [
            # Front face
            [0.0, 0.0, 0.0],
            [1.0, 0.0, 0.0],
            [1.0, 1.0, 0.0],
            [0.0, 1.0, 0.0],
            # Back face
            [0.0, 0.0, 1.0],
            [1.0, 0.0, 1.0],
            [1.0, 1.0, 1.0],
            [0.0, 1.0, 1.0],
        ]

        indices = [# Front face
            0, 1, 2, 3,
            4, 5, 6, 7,
            0, 3, 7, 4,
            1, 2, 6, 5,
            2, 3, 7, 6,
            0, 1, 5, 4,]

        self.vertVBO = vbo.VBO(np.array(vertices, dtype=np.float32))
        self.vertVBO.bind()

        self.cubeIdxArray = vbo.VBO(np.array(indices, dtype=np.uint32),
                                    target=gl.GL_ELEMENT_ARRAY_BUFFER)
        self.cubeIdxArray.bind()
        
        self.cubeClrArray = np.array(
                [[0.0, 0.0, 0.0],
                 [1.0, 0.0, 0.0],
                 [1.0, 1.0, 0.0],
                 [0.0, 1.0, 0.0],
                 [0.0, 0.0, 1.0],
                 [1.0, 0.0, 1.0],
                 [1.0, 1.0, 1.0],
                 [0.0, 1.0, 1.0 ]])
        self.colorVBO = vbo.VBO(np.reshape(self.cubeClrArray,
                                           (1, -1)).astype(np.float32))
        self.colorVBO.bind()

    def setRot(self, x,y,z):
        self.rotX = z
        self.rotY = x
        self.rotZ = y
        self.update()


class BluetoothThread(QThread):
    data_received = pyqtSignal(str)
    
    def __init__(self, device_name, drawing_widget,glWidget):
        super().__init__()
        self.device_name = device_name
        self.target_address = None
        self.drawing_widget = drawing_widget
        self.glWidget =glWidget
        self.x_pos_new=x_pos
        self.y_pos_new=y_pos
        self.rot_en=True
        self.rot_en_in=False
        self.prev_pitch=0
        self.x=0.0
        self.y=0.0
        self.z=0.0
        
    def run(self):
        nearby_devices = bluetooth.discover_devices()
        for bdaddr in nearby_devices:
            if self.device_name == bluetooth.lookup_name(bdaddr):
                self.target_address = bdaddr
                break

        if self.target_address is not None:
            print ("found target bluetooth device with address ", self.target_address)
        else:
            print ("could not find target bluetooth device nearby")
            self.data_received.emit("No Device Found")
            return

        port = 1
        s = socket.socket(socket.AF_BLUETOOTH, socket.SOCK_STREAM, socket.BTPROTO_RFCOMM)
        size = 2048
        try:
            s.connect((self.target_address, port))
        except socket.error as e:
            print(f"Error connecting to device: {e}")
            self.data_received.emit("No Device Found")
            return

        print("CONNECTED")
        d = "0"
        s.send(d.encode())
    
        while True:
            global x_pos, y_pos,rot_const,x,y,z
            self.x,self.y,self.z=x,y,z
            data = b''
            while len(data) < 8:
                data += s.recv(1)
            self.x, self.y, self.z, r = struct.unpack('<hhhh', data[:8])
            self.z=self.z/100
            y_value = self.x / 100
            r_value = r / 1
            if(self.rot_en_in and r and comp_mode):
                r_value= int(r/1+((self.z-self.prev_pitch)/rot_const))
                self.rot_en=False
            self.data_received.emit(f"x={self.x/100}, y={self.y/100}, z={self.z} ,r={r/1},_r={rot_const}")
            self.glWidget.setRot(self.x/100,self.y/100,self.z)
            data = data[8:]
            self.prev_pitch=self.z
            self.x_pos_new = x_pos + r_value * math.cos(math.radians(y_value))
            self.y_pos_new = y_pos + r_value * math.sin(math.radians(y_value))
            self.drawing_widget.addLine(self.x_pos_new, self.y_pos_new,x_pos,y_pos)
            x_pos = self.x_pos_new
            y_pos = self.y_pos_new
            if(r and self.rot_en and comp_mode):
                self.rot_en_in=True

        s.close()


class DrawingWidget(QWidget):
    def __init__(self, parent=None):
        super().__init__(parent)
        self.path = QPainterPath()
        self.points = []
        self.scale_factor = 1.0
        
    def paintEvent(self, event):
        qp = QPainter(self)
        qp.fillRect(event.rect(), QColor(0, 0, 0))
        pen = QPen(QColor(255, 255, 255))
        pen.setWidth(2)
        qp.setPen(pen)

        # Adjust the coordinate system to make the center of the widget the origin
        qp.translate(self.width() / 2, self.height() / 2)
        qp.scale(self.scale_factor, -self.scale_factor)

        # Draw the path using the adjusted coordinate system
        qp.drawPath(self.path)

    def wheelEvent(self, event):
        delta = event.angleDelta().y()
        if delta > 0:
            self.scale_factor *= 1.1
        else:
            self.scale_factor /= 1.1
        self.update()

    def addLine(self, x1, y1, x2, y2):
        if x1 != x2 or y1 != y2:
            self.path.lineTo(x2, y2)
            self.points.append((x2, y2))

        self.update()


class MetricsWidget(QWidget):
    def __init__(self):
        super().__init__(parent=None)
        self.scale_factor = 1.0
        self.path = QPainterPath()
        self.points=[]
        self.area = 0.0
        self.perimeter=0.0
        self.xs=0.0
        self.ys=0.0
        self.xe=0.0
        self.ye=0.0
        self.displacement=0.0
        self.x_displacement=0.0
        self.y_displacement=0.0
        self.penBl = QPen(Qt.blue, 2, Qt.SolidLine)
        self.penWt = QPen(Qt.white, 2, Qt.SolidLine)
        self.penGr = QPen(Qt.green, 2, Qt.SolidLine)

    def displayMetrics(self,coordinates):
        self.points=coordinates
        self.xs,self.ys=map(int, self.points[1])
        self.xe,self.ye=map(int, self.points[-1])
        self.calculate_area()
        self.perimeter = sum(QLineF(QPointF(*p1), QPointF(*p2)).length() for p1, p2 in zip(self.points, self.points[1:]))
        self.displacement = math.hypot(self.xe - self.xs, self.ye - self.ys)
        self.x_displacement = self.xe - self.xs
        self.y_displacement = self.ye - self.ys
        # result_label = QLabel(f"Area: {self.area:.2f}\nPerimeter: {self.perimeter:.2f}")
        # print(f"Area: {self.area:.2f}\nPerimeter: {self.perimeter:.2f}\n")
        self.update()

    def paintEvent(self,e):
        qp = QPainter(self)
        qp.fillRect(e.rect(), QColor(0, 0, 0))
        qp.translate(self.width() / 2, self.height() / 2)
        qp.scale(1, -1)
        qp.scale(self.scale_factor, -self.scale_factor)
        if((self.xs and self.xe and self.ys and self.ye)!=None):
            self.draw_lines(qp)
            self.draw_polygon(qp)
            self.drawPoint(qp)
            self.drawDisplacement(qp)
    
    def wheelEvent(self, event):
        delta = event.angleDelta().y()
        if delta > 0:
            self.scale_factor *= 1.1
        else:
            self.scale_factor /= 1.1
        self.update()

    def drawPoint(self,qp):
        qp.setPen(QPen(Qt.red, 8))
        if len(self.points) >= 1:
            qp.drawPoint(self.xs, self.ys)
            qp.setPen(QPen(Qt.blue, 8))
            qp.drawPoint(self.xe, self.ye)

    def drawDisplacement(self,qp):
        qp.setPen(self.penGr)
        qp.drawLine(int(self.xs), int(self.ys), int(self.xe), int(self.ye))
        qp.setPen(self.penWt)
        qp.drawLine(int(self.xs), int(self.ys), int(self.xs + self.x_displacement), int(self.ys))
        qp.setPen(self.penBl)
        qp.drawLine(int(self.xs), int(self.ys), int(self.xs), int(self.ys + self.y_displacement))

    def draw_lines(self, qp):
        pen = QPen(Qt.black, 2, Qt.SolidLine)
        qp.setPen(pen)
        for i in range(len(self.points) - 1):
            x1, y1 = map(int, self.points[i])
            x2, y2 = map(int, self.points[i+1])
            qp.drawLine(int(x1), int(y1), int(x2), int(y2))

    def draw_polygon(self, qp):
        polygon = QPolygon([QPoint(int(p[0]), int(p[1])) for p in self.points])
        brush = Qt.yellow
        qp.setBrush(brush)
        qp.drawPolygon(polygon)     

    def calculate_area(self):
        n = len(self.points) 
        for i in range(n):
            j = (i + 1) % n
            self.area += self.points[i][0] * self.points[j][1] - self.points[j][0] * self.points[i][1]
        self.area=abs(self.area)/2


class MainWindow(QWidget):
    def __init__(self):
        super().__init__()
        self.setWindowTitle("Accelerometer Data Visualization")
        self.setGeometry(100, 100, 1000, 3000)
        self.feature_collection = {"type": "FeatureCollection", "features": []}
        global rot_const
        # Create a combo box to select the Bluetooth device to connect to
        self.device_combo = QComboBox()
        self.device_combo.setMaximumWidth(300)
        self.device_combo.addItems([bluetooth.lookup_name(address) for address in bluetooth.discover_devices()])

        self.connect_button = QPushButton("Connect")
        self.connect_button.clicked.connect(self.connect_clicked)

        # Create a label to display the selected Bluetooth device
        self.data_recv_label = QLabel()
        self.metric_label = QLabel()

        # Create a frame for the label
        self.data_recv_frame = QFrame()
        self.data_recv_frame.setFrameShape(QFrame.WinPanel)
        self.data_recv_frame.setFrameShadow(QFrame.Sunken)
        self.data_recv_frame.setAutoFillBackground(True)

        self.reset_button = QPushButton("Reset")
        self.reset_button.clicked.connect(self.reset_clicked)

        self.generate_button = QPushButton("Generate")
        self.generate_button.clicked.connect(self.generate_button_clicked)

        self.geojson_button = QPushButton("Save-GeoJSON")
        self.geojson_button.clicked.connect(self.geoJsonSave)
        self.geojson_button.setEnabled(False)

        self.viewjson_button = QPushButton("View-GeoJSON")
        self.viewjson_button.clicked.connect(self.viewGeoJSON)

        # Create a QDoubleSpinBox widget with a default value of 0.0
        self.length_const = QDoubleSpinBox()
        self.length_const.setRange(-10.0, 10.0)
        self.length_const.setSingleStep(0.01)
        self.length_const.setValue(0.17)

        self.rotation_const = QDoubleSpinBox()
        self.rotation_const.setRange(-360.0,360.0)
        self.rotation_const.setSingleStep(0.5);
        self.rotation_const.setValue(30)
        rot_const=360/self.rotation_const.value()

        constant_layout = QHBoxLayout()
        constant_layout.addWidget(QLabel("Length Const:"))
        constant_layout.addWidget(self.length_const)

        rotation_const_laout = QHBoxLayout()
        rotation_const_laout.addWidget(QLabel("Steps/Rotation:"))
        rotation_const_laout.addWidget(self.rotation_const)

        self.compensator_Switch = QPushButton('Compensator', self)
        self.compensator_Switch.setCheckable(True)
        self.compensator_Switch.move(110, 20)
        self.compensator_Switch.clicked[bool].connect(self.compensatorMode)

        settings_layout =QVBoxLayout()
        settings_layout.addWidget(self.compensator_Switch)
        settings_layout.addLayout(constant_layout)
        settings_layout.addLayout(rotation_const_laout)

        # Button UI
        self.metric_plot = MetricsWidget()
        self.metric_plot.setVisible(True)

        # Add the label to the frame
        frame_layout = QVBoxLayout()
        frame_layout.addWidget(self.data_recv_label)
        frame_layout.addWidget(self.metric_label)
        self.data_recv_frame.setLayout(frame_layout)

        # Create a layout for plotter
        self.paint_plot = DrawingWidget() 
        self.paint_plot.setVisible(True)
        
        plotLayout = QVBoxLayout()
        plotLayout.addWidget(self.paint_plot)
        plotLayout.addWidget(self.metric_plot)

        #Glwidget
        self.glWidget = GLWidget()

        buttons_layout = QVBoxLayout()
        buttons_layout.addWidget(self.glWidget)
        buttons_layout.addWidget(QLabel("Select Bluetooth Device: "))
        buttons_layout.addWidget(self.device_combo)
        buttons_layout.addWidget(self.connect_button)

        # Add the QDoubleSpinBox widget and label to the layout
        buttons_layout.addLayout(settings_layout)

        buttons_layout.addWidget(self.generate_button)
        buttons_layout.addWidget(self.reset_button)
        buttons_layout.addWidget(self.geojson_button)
        buttons_layout.addWidget(self.viewjson_button)
        buttons_layout.addWidget(self.data_recv_frame)

        # Create a layout for the UI
        layout = QHBoxLayout()
        layout.addLayout(plotLayout, 3)
        layout.addLayout(buttons_layout, 2)     

        self.setLayout(layout)
        self.thread = None

    def viewGeoJSON(self):
        vpoints=[]
        self.feature_collection = {"type": "FeatureCollection", "features": []}
        # prompt the user to select a file to load
        options = QFileDialog.Options()
        options |= QFileDialog.DontUseNativeDialog
        filename, _ = QFileDialog.getOpenFileName(self, "Open file", "", "GeoJSON Files (*.geojson)", options=options)
        
        if filename:
            with open(filename) as f:
                data = json.load(f)

            for feature in data['features']:
                if feature['geometry']['type'] == 'Point':
                    x, y = feature['geometry']['coordinates']
                    vpoints.append((x,y))

            self.metric_plot.displayMetrics(vpoints)
            self.metric_label.setText(f"Area:{self.metric_plot.area*self.length_const.value():.2f}\nDistance:{self.metric_plot.perimeter*self.length_const.value():.2f}\nDisplacement:{self.metric_plot.displacement*self.length_const.value():.2f}\nPerimeter:{self.metric_plot.perimeter*self.length_const.value()}\nX-Displacement:{self.metric_plot.x_displacement*self.length_const.value()}\nY-Displacement:{self.metric_plot.y_displacement*self.length_const.value()}\n")

    def geoJsonSave(self):
        # create a GeoJSON feature collection object
        if 'features' not in self.feature_collection:
            self.feature_collection['features'] = []
        for point in self.metric_plot.points:
            x,y = point
            self.feature_collection['features'].append({"type": "Feature", "geometry": {"type": "Point", "coordinates": [x, y]}})
        # prompt the user to choose a filename and location
        options = QFileDialog.Options()
        options |= QFileDialog.DontUseNativeDialog
        filename, _ = QFileDialog.getSaveFileName(self, "Save file", "", "GeoJSON Files (*.geojson)", options=options)
        
        if filename:
            with open(filename, "w") as outfile:
                json.dump(self.feature_collection, outfile)
        
    def compensatorMode(self,pressed):
        global comp_mode
        if pressed:
            comp_mode=True
        else:
            comp_mode=False
        
    def generate_button_clicked(self):
        coordinates=self.paint_plot.points
        self.metric_plot.displayMetrics(coordinates)
        self.geojson_button.setEnabled(True)
    
    def connect_clicked(self):
        device_name = self.device_combo.currentText()
        
        if self.thread is not None:
            self.thread.terminate()
        self.thread = BluetoothThread(device_name,self.paint_plot,self.glWidget)
        self.thread.data_received.connect(self.data_received_text)
        self.thread.finished.connect(self.connect_finished)
        self.connect_button.setEnabled(False)
        self.thread.start()
    
    def data_received_text(self, data):
        self.data_recv_label.setText(data)
        self.metric_label.setText(f"Area:{self.metric_plot.area*self.length_const.value():.2f}\nDistance:{self.metric_plot.perimeter*self.length_const.value():.2f}\nDisplacement:{self.metric_plot.displacement*self.length_const.value():.2f}\nPerimeter:{self.metric_plot.perimeter*self.length_const.value()}\nX-Displacement:{self.metric_plot.x_displacement*self.length_const.value()}\nY-Displacement:{self.metric_plot.y_displacement*self.length_const.value()}\n")

    def connect_finished(self):
        self.connect_button.setEnabled(True)

    def reset_clicked(self):
        self.geojson_button.setEnabled(False)
        self.paint_plot.path = QPainterPath()
        self.metric_plot.path=QPainterPath()
        self.paint_plot.update()
        self.metric_plot.update()
        global x_pos, y_pos,rot_const
        x_pos = 0
        y_pos = 0
        rot_const=360/self.rotation_const.value()
        self.paint_plot.points.clear()
        self.metric_plot.points.clear()
        self.metric_plot.area=0.0
        self.metric_plot.perimeter=0.0
        self.metric_plot.xs=0.0
        self.metric_plot.xe=0.0
        self.metric_plot.ys=0.0
        self.metric_plot.ye=0.0
        self.metric_plot.x_displacement=self.metric_plot.y_displacement=0.0
        self.metric_plot.displacement=0.0
        self.feature_collection.clear()
        self.metric_label.clear()
        
    def handle_text_changed(self, text):
        self.textbox.insertPlainText(text)
        self.textbox.insertPlainText("\n")
        self.keyboard.type(text)


if __name__ == '__main__':
    app = QApplication(sys.argv)
    window = MainWindow()
    window.show()
    sys.exit(app.exec_())

Arduino Code :

#include <ArduinoJson.h>
#include "I2Cdev.h"
#include <SoftwareSerial.h>
#include "MPU6050_6Axis_MotionApps20.h"
#include <Wire.h>

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

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

//#define OUTPUT_READABLE_YAWPITCHROLL_SERIAL
#define OUTPUT_READABLE_YAWPITCHROLL_SERIAL1

char buff[100];
#define BAUD_RATE 9600
#define INTERRUPT_PIN 2  // use pin 2 on Arduino Uno & most boards

// 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


const int encoderPinA = 4;
const int encoderPinB = 5;
int previousEncoderState = 0;
int currentEncoderState = 0;
int encoderPosition = 0,temp=0;
// ================================================================
// ===               INTERRUPT DETECTION ROUTINE                ===
// ================================================================

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

// ================================================================
// ===                      INITIAL SETUP                       ===
// ================================================================

void setup() {
    pinMode(encoderPinA, INPUT);
    pinMode(encoderPinB, INPUT);
    #if I2CDEV_IMPLEMENTATION == I2CDEV_ARDUINO_WIRE
        Wire.begin();
        Wire.setClock(400000); 
    #elif I2CDEV_IMPLEMENTATION == I2CDEV_BUILTIN_FASTWIRE
        Fastwire::setup(400, true);
    #endif

    Serial.begin(BAUD_RATE);
    #ifdef OUTPUT_READABLE_YAWPITCHROLL_SERIAL1
           Serial1.begin(BAUD_RATE);
    #endif
    
//    while (!Serial);
//    // initialize device
//    Serial.println(F("Initializing I2C devices..."));
//    mpu.initialize();
//    pinMode(INTERRUPT_PIN, INPUT);
//    // verify connection
//    Serial.println(F("Testing device connections..."));
//    Serial.println(mpu.testConnection() ? F("MPU6050 connection successful") : F("MPU6050 connection failed"));
//    // 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
    while (!Serial1);
    
    mpu.initialize();
    pinMode(INTERRUPT_PIN, INPUT);
    if(Serial1.available())
    Serial.println(mpu.testConnection() ? F("P") : F("F"));
    while (Serial1.available() && Serial1.read()); // empty buffer
    while (!Serial1.available());                 // wait for data
    while (Serial1.available() && Serial1.read()); // empty buffer again
    

    // load and configure the DMP
    //Serial1.println(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) {
        // Calibration Time: generate offsets and calibrate our MPU6050
        mpu.CalibrateAccel(6);
        mpu.CalibrateGyro(6);
        mpu.PrintActiveOffsets();
        // turn on the DMP, now that it's ready
        Serial.println(F("Enabling DMP..."));
        mpu.setDMPEnabled(true);

        // enable Arduino interrupt detection
        Serial.print(F("Enabling interrupt detection (Arduino external interrupt "));
        Serial.print(digitalPinToInterrupt(INTERRUPT_PIN));
        Serial.println(F(")..."));
        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
        Serial.println(F("DMP ready! Waiting for first interrupt..."));
        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)
        Serial.print(F("DMP Initialization failed (code "));
        Serial.print(devStatus);
        Serial.println(F(")"));
    }
}

void rotEnc() {
// Read the state of the rotary encoder
previousEncoderState = currentEncoderState;
currentEncoderState = digitalRead(encoderPinA) << 1 | digitalRead(encoderPinB);

// Check for rotary encoder movement
if (previousEncoderState != currentEncoderState) 
{
  if ((previousEncoderState == 0b00 && currentEncoderState == 0b01) ||(previousEncoderState == 0b01 && currentEncoderState == 0b11) ||
      (previousEncoderState == 0b11 && currentEncoderState == 0b10) || (previousEncoderState == 0b10 && currentEncoderState == 0b00)) 
      {
       encoderPosition++;
      } 
  else 
      {
        encoderPosition--;
      }
  }
}

void loop() {
    rotEnc();
    // if programming failed, don't try to do anything
    if (!dmpReady) return;
    // read a packet from FIFO
    if (mpu.dmpGetCurrentFIFOPacket(fifoBuffer)) { // Get the Latest packet 

        
        #ifdef OUTPUT_READABLE_YAWPITCHROLL_SERIAL
            mpu.dmpGetQuaternion(&q, fifoBuffer);
            mpu.dmpGetGravity(&gravity, &q);
            mpu.dmpGetYawPitchRoll(ypr, &q, &gravity);
            Serial.print(ypr[0] * 180/M_PI);
            Serial.print(",");
            Serial.print(ypr[1] * 180/M_PI);
            Serial.print(",");
            Serial.print(ypr[2] * 180/M_PI);
            Serial.print(",");
            Serial.println(encoderPosition);
            
        #endif    

        #ifdef OUTPUT_READABLE_YAWPITCHROLL_SERIAL1
            // display Euler angles in degrees
//            Serial1.println("HELLO/n");
            mpu.dmpGetQuaternion(&q, fifoBuffer);
            mpu.dmpGetGravity(&gravity, &q);
            mpu.dmpGetYawPitchRoll(ypr, &q, &gravity);

            temp=encoderPosition-temp;
            int16_t x=ypr[0]*180/M_PI * 100;
            int16_t y=ypr[1]*180/M_PI * 100;
            int16_t z=ypr[2]*180/M_PI * 100;
            int16_t r = (int16_t) temp;
            byte buf[8];
            buf[0] = x & 255;
            buf[1] = (x >> 8) & 255;
            buf[2] = y & 255;
            buf[3] = (y >> 8) & 255;
            buf[4] = z & 255;
            buf[5] = (z >> 8) & 255;
            buf[6] = r & 255;
            buf[7] = (r >> 8) & 255;
            
            Serial1.write(buf,sizeof(buf)); 
            temp=encoderPosition;
//            Serial1.print(ypr[0]*180/M_PI);
//            Serial1.print(",");
//            Serial1.print(ypr[1]*180/M_PI);
//            Serial1.print(",");
//            Serial1.println(ypr[2]*180/M_PI);
          
        #endif 
   
    }
}