IMU with bluetooth Module

I am currently working on an arduino project where I have to wirelessly transmit data from an IMU (composed of an AXDL 345 and ITG3200) to a laptop. I have tried different codes and none seem to be getting me anywhere. I am connecting using COM4

Has anyone done a project like this?

Right now, I have my arudino uno connected to my laptop by USB.

First part of the code:

#include <SoftwareSerial.h>  //BT.
#include "I2Cdev.h"
#include "MPU6050_6Axis_MotionApps20.h"

    #include "Wire.h"

MPU6050 mpu;
//MPU6050 mpu(0x68); // <-- use for AD0 high

// uncomment "OUTPUT_READABLE_QUATERNION" if you want to see the actual
// quaternion components in a [w, x, y, z] format (not best for parsing
// on a remote host such as Processing or something though)

// uncomment "OUTPUT_READABLE_EULER" if you want to see Euler angles
// (in degrees) calculated from the quaternions coming from the FIFO.
// Note that Euler angles suffer from gimbal lock (for more info, see

// uncomment "OUTPUT_READABLE_YAWPITCHROLL" if you want to see the yaw/
// pitch/roll angles (in degrees) calculated from the quaternions coming
// from the FIFO. Note this also requires gravity vector calculations.
// Also note that yaw/pitch/roll angles suffer from gimbal lock (for
// more info, see:

// 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.

// 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.

// uncomment "OUTPUT_TEAPOT" if you want output that matches the
// format used for the InvenSense teapot demo

#define LED_PIN 13 // (Arduino is 13, Teensy is 11, Teensy++ is 6)
bool blinkState = false;
int bluetoothData; // BT. "the data given from Computer".
SoftwareSerial mySerial(10, 11); // BT. "RX, TX".

// 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[128]; // FIFO storage buffer. //BT, default 64.

// 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

// packet structure for InvenSense teapot demo
uint8_t teapotPacket[14] = { '

my IMU is connected as such:
SCL - A5
SDA - A4
3.3v - 3.3v

My HC-05 is connected as such:
Vcc - 5v
TXD - RX, 0x02, 0,0, 0,0, 0,0, 0,0, 0x00, 0x00, ‘\r’, ‘\n’ };

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

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

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

void setup() {
    // join I2C bus (I2Cdev library doesn’t do this automatically)
        TWBR = 24; // 400kHz I2C clock (200kHz if CPU is 8MHz)
        Fastwire::setup(400, true);
    // 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(9600); //Default 115200. 9600 sync with BT.
    while (!Serial); // wait for Leonardo enumeration, others continue immediately

// 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.

mySerial.begin(9600);  //BT.
    //mySerial.println(“Bluetooth On, standby for data from gyro…”);

// initialize device
    //mySerial.println(F(“Initializing I2C devices…”));

my IMU is connected as such:
SCL - A5
SDA - A4
3.3v - 3.3v

My HC-05 is connected as such:
Vcc - 5v

Second part:


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

    // load and configure the DMP
    //mySerial.println(F("Sarom Chhin 2014"));  //BT
    //mySerial.println(F("Senior Project; 409B Independent Studies."));  //BT
    //delay(4000); //BT.
    //mySerial.println(F("Starting gyro+accel module!"));  //BT.
    //delay(500); //BT.
    //mySerial.println(F("(Initializing DMP...)"));
    //delay(500); //BT. 
    devStatus = mpu.dmpInitialize();

    // supply your own gyro offsets here, scaled for min sensitivity
    mpu.setZAccelOffset(1988); // 1988 best so far, w z=220's. Default = 1788.

    // make sure it worked (returns 0 if so)
    if (devStatus == 0) {
        // turn on the DMP, now that it's ready
        //mySerial.println(F("(Enabling DMP...)"));
        //delay(500); //BT.
        // enable Arduino interrupt detection
        //mySerial.println(F("External interrupt detected."));  //BT. Default: ""Enabling interrupt detection (Arduino external interrupt 0)..."));
        //delay(500); //BT.
        attachInterrupt(0, dmpDataReady, RISING); //MOD. "0" is the interrupt (int.0 = pin2 for UNO),     
        //attachInterrupt(0, dmpDataReady, CHANGE); //BT. Default is "RISING".     
        mpuIntStatus = mpu.getIntStatus();

        // set our DMP Ready flag so the main loop() function knows it's okay to use it
        //mySerial.println(F("DMP ready! Waiting for first interrupt..."));
        //mySerial.println(F("____________________________"));  //BT
        //mySerial.println(F("        Yaw     Pitch   Roll"));  //BT.
        //mySerial.println(F("         X        Y      Z"));  //BT.
        //mySerial.println(F("----------------------------"));  //BT.
        //delay(4000); //BT.
        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)
        mySerial.print(F("DMP Initialization failed (code "));

    // configure LED for output
    pinMode(LED_PIN, OUTPUT);

// ================================================================
// ===                    MAIN PROGRAM LOOP                     ===
// ================================================================

void loop() {
    // 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
        // .
        // .
        // .

    // 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
        Serial.println(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();

        // 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;

            // display quaternion values in easy matrix form: w x y z
            //mpu.dmpGetQuaternion(&q, fifoBuffer);

        //#ifdef OUTPUT_READABLE_EULER
            // display Euler angles in degrees
            //mpu.dmpGetQuaternion(&q, fifoBuffer);
            //mpu.dmpGetEuler(euler, &q);
            //Serial.print(euler[0] * 180/M_PI);
            //Serial.print(euler[1] * 180/M_PI);
            //Serial.println(euler[2] * 180/M_PI);

            // display Euler angles in degrees
            mpu.dmpGetQuaternion(&q, fifoBuffer);
            mpu.dmpGetGravity(&gravity, &q);
            mpu.dmpGetYawPitchRoll(ypr, &q, &gravity);
            mySerial.print(ypr[0] * 180/M_PI);
            mySerial.print(ypr[1] * 180/M_PI);
            mySerial.println(ypr[2] * 180/M_PI);
            delay(500); //BT.
            // display real acceleration, adjusted to remove gravity
            mpu.dmpGetQuaternion(&q, fifoBuffer);
            mpu.dmpGetAccel(&aa, fifoBuffer);
            mpu.dmpGetGravity(&gravity, &q);
            mpu.dmpGetLinearAccel(&aaReal, &aa, &gravity);
            delay(200); //BT.
            // 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);
            //mySerial.println(aaWorld.z - 220); //BT. -220 Calibrated to board being parallel to Earth. 
            mySerial.println(abs(aaWorld.z -360));
            delay(100); //BT.
        #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];
            Serial.write(teapotPacket, 14);
            teapotPacket[11]++; // packetCount, loops at 0xFF on purpose

        // blink LED to indicate activity
        blinkState = !blinkState;
        digitalWrite(LED_PIN, blinkState);

I can only guess, but that code just might be one programme in two parts. If you got rid of all the junk, unnecessary whitespace, and irrelevant comments, you might be able to present it in one piece, so that other people might read it.

You might also be a bit more forthcoming about what you mean by "getting nowhere". You could start with any "somewhere" you have, like does the IMU, whatever that is, work without bluetooth, and can you send a simple "hello" via bluetooth without IMU getting in the way?

I'm guessing that this might well not be an Arduino problem anyway, and all the problems are at the laptop end, i.e. improper use of its bluetooth, or improper use of your terminal.

It is good practice to wire Arduino Tx through a 1k/2k voltage divider. It is not usually fatal if you don't.
You might find the following background notes useful