ofSerial&MPU6050 : Fail to receive data on OF

#1

Hi,
I’m a freshman here to learn to use OF to control my Arduino nano. And for now, I am working on my project with Arduino nano and Accelerometer MPU6050. I would like to receive MPU6050’s data through Arduino and visualize the sensors’ motion in OF. Before I wrote my code, I found an example connect Arduino, MPU6050 with Processing(https://maker.pro/arduino/tutorial/how-to-interface-arduino-and-the-mpu-6050-sensor[https://maker.pro/arduino/tutorial/how-to-interface-arduino-and-the-mpu-6050-sensor], the effect of which is really near my expectation. So I decided to rewrite it in OF., using ofSerial. Unfortunately, it didn’t work.

I can’t set the breakpoint cuz my Arduino needs some time to initialize so the breakpoint always suggests that the value is 0, or null. I used “printf” to check some key values but there is nothing I can see.

This is my code (to prevent missing some unknown stupid mistakes I made, please check of it.) draw a box and hope it can rotate as MPU6050 do.

This is ofApp.h.

#pragma once

#include "ofMain.h"

#pragma once

#include "ofMain.h"

class ofApp : public ofBaseApp{
   
    
	public:
		void setup();
		void update();
    
		void draw();

		void keyPressed(int key);
		void keyReleased(int key);
		void mouseMoved(int x, int y );
		void mouseDragged(int x, int y, int button);
		void mousePressed(int x, int y, int button);
		void mouseReleased(int x, int y, int button);
		void mouseEntered(int x, int y);
		void mouseExited(int x, int y);
		void windowResized(int w, int h);
		void dragEvent(ofDragInfo dragInfo);
		void gotMessage(ofMessage msg);
   private:
        ofQuaternion serialEvent(ofSerial port);
    
        ofSerial  serial;
        ofEasyCam cam;
        ofNode mpuNode
    
};

This is ofApp.cpp.

#include "ofApp.h"

unsigned char receivedData[14];

ofQuaternion mpuquat;

//--------------------------------------------------------------
ofQuaternion ofApp::serialEvent(ofSerial port){
    
    ofQuaternion quat;
    char teapotPacket[14];
    int serialCount = 0;                 // current packet byte position
    int aligned = 0;
    float q[4];
    
    if (port.available() > 0) {
        port.readBytes(receivedData, 14);
        char *tmp_data = (char*)receivedData;
        teapotPacket[0] = tmp_data[0];
        teapotPacket[1] = tmp_data[1];
        teapotPacket[2] = tmp_data[2];
        teapotPacket[3] = tmp_data[3];
        teapotPacket[4] = tmp_data[4];
        teapotPacket[5] = tmp_data[5];
        teapotPacket[6] = tmp_data[6];
        teapotPacket[7] = tmp_data[7];
        teapotPacket[8] = tmp_data[8];
        teapotPacket[9] = tmp_data[9];
        teapotPacket[10] = tmp_data[10];
        teapotPacket[11] = tmp_data[11];
        teapotPacket[12] = tmp_data[12];
        teapotPacket[13] = tmp_data[13];
        
        for(int n=0; n < 14; n++){
            printf("%d", teapotPacket[n]);
            if (teapotPacket[n] == '$') {serialCount = 0;}
            // this will help with alignment
            if (aligned < 4) {
                // make sure we are properly aligned on a 14-byte packet
                if (serialCount == 0) {
                    if (teapotPacket[n] == '$') aligned++; else aligned = 0;
                } else if (serialCount == 1) {
                    if (teapotPacket[n] == 2) aligned++; else aligned = 0;
                } else if (serialCount == 12) {
                    if (teapotPacket[n] == '\r') aligned++; else aligned = 0;
                } else if (serialCount == 13) {
                    if (teapotPacket[n] == '\n') aligned++; else aligned = 0;
                }
                //println(ch + " " + aligned + " " + serialCount);
                serialCount++;
                if (serialCount == 14) serialCount = 0;
            } else {
                if (serialCount > 0 || teapotPacket[n] == '$') {
                    teapotPacket[serialCount++] = teapotPacket[n];
                    if (serialCount == 14) {
                        serialCount = 0; // restart packet byte position
                        
                        // get quaternion from data packet
                        q[0] = ((teapotPacket[2] << 8) | teapotPacket[3]) / 16384.0f;
                        q[1] = ((teapotPacket[4] << 8) | teapotPacket[5]) / 16384.0f;
                        q[2] = ((teapotPacket[6] << 8) | teapotPacket[7]) / 16384.0f;
                        q[3] = ((teapotPacket[8] << 8) | teapotPacket[9]) / 16384.0f;
                        for (int i = 0; i < 4; i++) if (q[i] >= 2) q[i] = -4 + q[i];
                        
                        // set our toxilibs quaternion to new data
                        quat.set(q[0], q[1], q[2], q[3]);
                        
                    }
                }
            }
        }
    }
   // cout << teapotPacket[0] << teapotPacket[1] << teapotPacket[2] << teapotPacket[3] << endl;
    return quat;
    
}


void ofApp::setup(){
    serial.listDevices();
    vector <ofSerialDeviceInfo> deviceList = serial.getDeviceList();
    int baud = 115200;
    serial.setup("/dev/cu.usbserial-A100ASV2", baud);
    
    ofSetFrameRate(120);
    ofSetVerticalSync(true);
    ofSetLogLevel(OF_LOG_VERBOSE);
    
    cam.setOrientation(ofPoint(-20, 0, 0));
}

//--------------------------------------------------------------
void ofApp::update(){
    
    

}


//--------------------------------------------------------------
void ofApp::draw(){
    ofEnableDepthTest();
    cam.begin();
    mpuquat = serialEvent(serial);
    mpuNode.transformGL();
    mpuNode.setPosition(0,0,0);
    mpuNode.setOrientation(mpuquat);
    // ofRotateX(mpu[1]);
    // ofRotateY(mpu[0]);
    // ofRotateZ(mpu[2]);
    ofNoFill();
    ofSetColor(255, 0, 0);
    ofDrawBox(0, 0, 0, 100,10,100);
    mpuNode.restoreTransformGL();
    cam.end();
    

}

//--------------------------------------------------------------
void ofApp::keyPressed(int key){
    

}

//--------------------------------------------------------------
void ofApp::keyReleased(int key){
    

}

//--------------------------------------------------------------
void ofApp::mouseMoved(int x, int y ){
    

}

//--------------------------------------------------------------
void ofApp::mouseDragged(int x, int y, int button){
    

    
}

//--------------------------------------------------------------
void ofApp::mousePressed(int x, int y, int button){
    

}

//--------------------------------------------------------------
void ofApp::mouseReleased(int x, int y, int button){
    

}

//--------------------------------------------------------------
void ofApp::mouseEntered(int x, int y){
    

}

//--------------------------------------------------------------
void ofApp::mouseExited(int x, int y){
    

}

//--------------------------------------------------------------
void ofApp::windowResized(int w, int h){
    

}

//--------------------------------------------------------------
void ofApp::gotMessage(ofMessage msg){

}

//--------------------------------------------------------------
void ofApp::dragEvent(ofDragInfo dragInfo){ 

}


I built successfully and ran, my box had no rotation and just stayed still. For a lil while, in the console, OF told me something was wrong.I have lil experience in c/c++, thus I can’t know more from my code, yet I can’t fix these errors and receive data correctly.

In the end, this is some clues Xcode showed me after running it.

Thanks!!!(A Deep Bow)

#2

I discussed with my friend, who specialized in C/C++. He wondered that maybe it is ofSerial class cannot be the parameter in the void. So the void I created is invalid (to receive data from other serial devices).

It’s an unnormal mistake, but hope freshmen can refer it if you guys have questions on ofSerial. And if OF is updated on this feature or the professionals know the right solution about this question, please tell me.:smile:

#3

UPDATE:I found my rewrite script is lil different from the original one. And I dont know what the differences are, I just found value they print is different. And I can’t get what i want from my script…

#4

Hi,
there are several problems in your code.
First, the way you use the ofSerial object is incorrect. passing it by value to the serialEvent function is not a good idea, it should be done by reference. But then, as the ofSerial object and serialEvent function are both members of ofApp there is no need to pass it as an argument, you can just refer to it.

Actually you can get rid of that serialEvent function you wrote and just put all that code inside the update function.

Then it is not a good idea to have the serial stuff inside the draw loop. It is better to have it in the update.

Take a look at the ofSerial documentation as you might want to put a while loop to make sure you catch all the data.

Another issue is the way you were trying to set the ofNode object in draw is wrong, although it might still work because of it being a member of ofApp and having its data to stay between frames.
you have the following

mpuNode.transformGL();
    mpuNode.setPosition(0,0,0);
    mpuNode.setOrientation(mpuquat);

but it should be

    mpuNode.setPosition(0,0,0);
    mpuNode.setOrientation(mpuquat);
   mpuNode.transformGL();

mpuNode.transfromGL() will set the current drawing matrices to what is stored in mpuNode, so setting the position and orientation after calling this function will have no (immediate) effect.

OF serial object works fine. The problem is that you are trying to copy and paste something made for processing, which works on a different way.

It should look something like this. I have not tested it just wrote it here but it should work. please let me know how it goes.

#pragma once
#include "ofMain.h"

class ofApp : public ofBaseApp{
public:
		void setup();
		void update();    
		void draw();

		void keyPressed(int key);
		void keyReleased(int key);
		void mouseMoved(int x, int y );
		void mouseDragged(int x, int y, int button);
		void mousePressed(int x, int y, int button);
		void mouseReleased(int x, int y, int button);
		void mouseEntered(int x, int y);
		void mouseExited(int x, int y);
		void windowResized(int w, int h);
		void dragEvent(ofDragInfo dragInfo);
		void gotMessage(ofMessage msg);
//   private:// no need to make this private
        ofQuaternion quat;
        ofSerial  serial;
        ofEasyCam cam;
        ofNode mpuNode
    unsigned char receivedData[14];

};

void ofApp::setup(){
    serial.listDevices();
    vector <ofSerialDeviceInfo> deviceList = serial.getDeviceList();
    int baud = 115200;
    serial.setup("/dev/cu.usbserial-A100ASV2", baud);
    
    ofSetFrameRate(120);
    ofSetVerticalSync(true);
    ofSetLogLevel(OF_LOG_VERBOSE);
    
    //cam.setOrientation(ofPoint(-20, 0, 0));// you dont really need this. you can just drag your mouse to move the camera
}

//--------------------------------------------------------------
void ofApp::update(){
    
    int bytesRequired = 14;
    
    int bytesRemaining = bytesRequired; 
    // loop until we've read everything. This is a reliable way of getting the data you need.
    while ( bytesRemaining > 0 ){
     // check for data
     if ( serial.available() > 0 ){
         // try to read - note offset into the receivedData[] array, this is so
         // that we don't overwrite the bytes we already have
         int bytesArrayOffset = bytesRequired - bytesRemaining;
         int result = serial.readBytes( &receivedData[bytesArrayOffset], bytesRemaining );
             // check for error code
         if ( result == OF_SERIAL_ERROR ){
             // something bad happened
             ofLog( OF_LOG_ERROR, "unrecoverable error reading from serial" );
             break;
         } else if ( result == OF_SERIAL_NO_DATA ){
             // nothing was read, try again
         } else {
             // we read some data!
             bytesRemaining -= result;
         }
     }
    }
    
// from here on it is what you have as this will depend on how you are sending your data.
    int serialCount = 0;                 // current packet byte position
    int aligned = 0;
    float q[4];
        for(int n=0; n < 14; n++){
            printf("%d", receivedData[n]);
            if (receivedData[n] == '$') {serialCount = 0;}
            // this will help with alignment
            if (aligned < 4) {
                // make sure we are properly aligned on a 14-byte packet
                if (serialCount == 0) {
                    if (receivedData[n] == '$') aligned++; else aligned = 0;
                } else if (serialCount == 1) {
                    if (receivedData[n] == 2) aligned++; else aligned = 0;
                } else if (serialCount == 12) {
                    if (receivedData[n] == '\r') aligned++; else aligned = 0;
                } else if (serialCount == 13) {
                    if (receivedData[n] == '\n') aligned++; else aligned = 0;
                }
                //println(ch + " " + aligned + " " + serialCount);
                serialCount++;
                if (serialCount == 14) serialCount = 0;
            } else {
                if (serialCount > 0 || receivedData[n] == '$') {
                    receivedData[serialCount++] = receivedData[n];
                    if (serialCount == 14) {
                        serialCount = 0; // restart packet byte position
                        
                        // get quaternion from data packet
                        q[0] = ((receivedData[2] << 8) | receivedData[3]) / 16384.0f;
                        q[1] = ((receivedData[4] << 8) | receivedData[5]) / 16384.0f;
                        q[2] = ((receivedData[6] << 8) | receivedData[7]) / 16384.0f;
                        q[3] = ((receivedData[8] << 8) | receivedData[9]) / 16384.0f;
                        for (int i = 0; i < 4; i++) if (q[i] >= 2) q[i] = -4 + q[i];
                        
                        quat.set(q[0], q[1], q[2], q[3]);
                        
                    }
                }
            }
        }
    }
//--------------------------------------------------------------
void ofApp::draw(){
    ofEnableDepthTest();
    cam.begin();
    
    mpuNode.setPosition(0,0,0);
    mpuNode.setOrientation(quat);
    // ofRotateX(mpu[1]);
    // ofRotateY(mpu[0]);
    // ofRotateZ(mpu[2]);
    mpuNode.transformGL();
    ofNoFill();
    ofSetColor(255, 0, 0);
    ofDrawBox(0, 0, 0, 100,10,100);
    mpuNode.restoreTransformGL();
    cam.end();
    

}
//--------------------------------------------------------------
void ofApp::keyPressed(int key){}
//--------------------------------------------------------------
void ofApp::keyReleased(int key){}
//--------------------------------------------------------------
void ofApp::mouseMoved(int x, int y ){}
//--------------------------------------------------------------
void ofApp::mouseDragged(int x, int y, int button){}
//--------------------------------------------------------------
void ofApp::mousePressed(int x, int y, int button){}
//--------------------------------------------------------------
void ofApp::mouseReleased(int x, int y, int button){}
//--------------------------------------------------------------
void ofApp::mouseEntered(int x, int y){}
//--------------------------------------------------------------
void ofApp::mouseExited(int x, int y){}
//--------------------------------------------------------------
void ofApp::windowResized(int w, int h){}
//--------------------------------------------------------------
void ofApp::gotMessage(ofMessage msg){}
//--------------------------------------------------------------
void ofApp::dragEvent(ofDragInfo dragInfo){}

Last but not least, if you want to make your life a lot easier while dealing with data transfers to and from the arduino use the ofxSerial addon, specially SerialPackage stufff which will auto check and you’ll have more consistent data with less code.

#5

Sorry that I haven’t shown my progress immediately.However, now my MPU6050 works perfectly after our debugging(me and my friend GAO) . This is my code, it can work although it may be not the best one.

ofApp.cpp

#include "ofApp.h"


ofQuaternion mpuquat;
int m=0;


//--------------------------------------------------------------

void ofApp::setup(){
    serial.listDevices();
    vector <ofSerialDeviceInfo> deviceList = serial.getDeviceList();
    int baud = 115200;
    serial.setup("/dev/cu.usbserial-A100ASV2", baud);
    
    ofSetFrameRate(240);
    ofSetVerticalSync(true);
    ofSetLogLevel(OF_LOG_VERBOSE);
    
    cam.setOrientation(ofPoint(-20, 0, 0));
    
    glDisable(GL_DEPTH_TEST);
    
    

    //openGL只能渲染最前面的东西,启用了之后,OpenGL在绘制的时候就会检查,当前像素前面是否有别的像素,如果别的像素挡道了它,那它就不会绘制,也就是说,OpenGL就只绘制最前面的一层。即打开深度;
   // glEnable(GL_BLEND);
    //混合模式,可以渲染半透明物体,但需要关闭glDisable(GL_DEPTH_TEST);
    
    // glColor4f(1.0f,1.0f,1.0f,0.5f); 而且还需要设置使用的透明度,这样就是一半的显示了,设置为1就是不透明
    
   // glBlendFunc(GL_SRC_ALPHA,GL_ONE); //基于源像素Alpha通道值的半透明混合函数
    
    //glEnable(GL_AUTO_NORMAL);自动生成法向
    glEnable(GL_NORMALIZE);
    //归一化,将所有向量变为(0,1)的单位向量
    //set help text to display by default
}

//--------------------------------------------------------------
void ofApp::update(){

    serial.writeByte('r');
        if ( serial.available() > 0 ){
    int bytesRequired = 14	;
    int bytesRemaining = bytesRequired;

    // loop until we've read everything. This is a reliable way of getting the data you need.


    while ( bytesRemaining > 0 ){
        // check for data
        if ( serial.available() > 0 ){
            // try to read - note offset into the receivedData[] array, this is so
            // that we don't overwrite the bytes we already have
            int bytesArrayOffset = bytesRequired - bytesRemaining;
            int result = serial.readBytes( &receivedData[bytesArrayOffset], bytesRemaining );
            //cout<<receivedData<<endl;
            // check for error code
            if ( result == OF_SERIAL_ERROR ){
                // something bad happened
                ofLog( OF_LOG_ERROR, "unrecoverable error reading from serial" );
                break;
            } else if ( result == OF_SERIAL_NO_DATA ){
                // nothing was read, try again
            } else {
                // we read some data!
                bytesRemaining -= result;
            }
        }
    }
        

    //cout << receivedData  << endl;
    // from here on it is what you have as this will depend on how you are sending your data.
            setquat(receivedData);

   
    }//else
    }

void ofApp::setquat(unsigned char teapotPacket[14]){
    int serialCount = 0;                 // current packet byte position
    int aligned = 0;
    float q[4];
    //cout << teapotPacket  << endl;
    // cout<<receivedData<<endl;
    //  if (receivedData[n] == '$') {serialCount = 0;}
    // this will help with alignment
    //cout << receivedData[0]  << endl;
    while (aligned < 4&&serialCount<8) {
        // make sure we are properly aligned on a 14-byte packet
        
        if (serialCount == 0) {
            if (teapotPacket[0] == '$') aligned++; else aligned = 0;
            //cout<<aligned<<endl;
        }
        if (serialCount == 1) {
            if (teapotPacket[1] == 2) aligned++; else aligned = 0;
            //cout<<aligned<<endl;
        }
        if (serialCount == 2 && aligned==2) {
            q[0] = ((teapotPacket[2] << 8) | teapotPacket[3]) / 16384.0f;
            q[1] = ((teapotPacket[4] << 8) | teapotPacket[5]) / 16384.0f;
            q[2] = ((teapotPacket[6] << 8) | teapotPacket[7]) / 16384.0f;
            q[3] = ((teapotPacket[8] << 8) | teapotPacket[9]) / 16384.0f;
            for (int i = 0; i < 4; i++) if (q[i] >= 2) q[i] = -4 + q[i];
            //cout<<q[0]<<q[1]<<q[2]<<q[3]<<endl;
            /*while(a<4){ q[a]=((serial.readByte()<<24)|(serial.readByte()<<16)|(serial.readByte()<<8)|(serial.readByte()<<0));
             cout<<q[a]<<endl;
             a++;
             }*/
            serialCount+=4;
        }
        if (serialCount == 6) {
            //q[0]=teapotPacket[2];
            //q[1]=teapotPacket[3];
            //q[2]=teapotPacket[4];
            //q[3]=teapotPacket[5];
            /*q[0] = ((teapotPacket[2] << 8) | teapotPacket[3]) / 16384.0f;
             q[1] = ((teapotPacket[4] << 8) | teapotPacket[5]) / 16384.0f;
             q[2] = ((teapotPacket[6] << 8) | teapotPacket[7]) / 16384.0f;
             q[3] = ((teapotPacket[8] << 8) | teapotPacket[9]) / 16384.0f;*/
            //for (int i = 0; i < 4; i++) if (q[i] >= 2) q[i] = -4 + q[i];
            
            //quat.set(q[0],q[1], q[2], q[3]);
            //cout << q[0] << q[1] << q[2] <<q[3]<< endl;
            if (teapotPacket[12] == '\r') aligned++; else aligned = 0;
            //cout << aligned << endl;
        }
        if (serialCount == 7) {
            if (teapotPacket[13] == '\n') aligned++; else aligned = 0;
            //cout << aligned << endl;
        }
        //cout<<aligned<<endl;
        //println(ch + " " + aligned + " " + serialCount);
        serialCount++;
        
    }//while
    serialCount=0;
    if(aligned==4) quat.set(q[0],-q[2], -q[3], -q[1]);
    cout << q[0] << q[1] << q[2] <<q[3]<< endl;
    //cout<<quat.x()<<quat.y()<<quat.z()<< quat.w()<<endl;
}

void ofApp::change(ofQuaternion q1) {
    if (q1.w() > 1) q1.normalize();
    float angle,x,y,z;
    angle = 2 * acos(q1.w())/3.14*180;
    float qw=q1.w();
    qw*=qw;
    double s = sqrt(1-qw);// assuming quaternion normalised then w is lessthan 1, so term always positive.
    if (s < 0.001) { // test to avoid divide by zero, s is always positive due to sqrt
        // if s close to zero then direction of axis not important
        x = q1.x(); // if it is important that axis is normalised then replace with x=1; y=z=0;
        y = q1.y();
        z = q1.z();
    } else {
        x = q1.x() / s; // normalise axis
        y = q1.y() / s;
        z = q1.z() / s;
    }
    quat.set(angle,x, y, z);
}


//--------------------------------------------------------------
void ofApp::draw(){
   // if (serial.available() > 0) {
    //    serial.readBytes(teapotPacket, 14);}
   // cout << teapotPacket[0] << teapotPacket[1] << teapotPacket[2] << teapotPacket[3] << endl;
    ofEnableDepthTest();
    cam.begin();

    //mpuNode.setPosition(0,0,0);
    //change(quat);
    // ofRotateX(mpu[1]);
    // ofRotateY(mpu[0]);
    // ofRotateZ(mpu[2]);
   /*if(oldquat!=quat){
        m++;
        if(m==20){m=0;
        
        oldquat=quat;
        cout<<quat.x()<<quat.y()<<quat.z()<< quat.w()<<endl;
        }
        }*/


        mpuNode.setOrientation(quat);
    //cout<<quat.x()<<quat.y()<<quat.z()<< quat.w()<<endl;
    //ofRotate(oldquat.x(),oldquat.y(), oldquat.z(), oldquat.w());
    mpuNode.transformGL();
    
    ofNoFill();
    ofSetColor(255, 0, 0);
    ofDrawBox(0, 0, 0, 100,10,100);
    mpuNode.restoreTransformGL();
    cam.end();

}

//--------------------------------------------------------------
void ofApp::keyPressed(int key){
    

}

//--------------------------------------------------------------
void ofApp::keyReleased(int key){
    

}

//--------------------------------------------------------------
void ofApp::mouseMoved(int x, int y ){
    

}

//--------------------------------------------------------------
void ofApp::mouseDragged(int x, int y, int button){
    

    
}

//--------------------------------------------------------------
void ofApp::mousePressed(int x, int y, int button){
    

}

//--------------------------------------------------------------
void ofApp::mouseReleased(int x, int y, int button){
    

}

//--------------------------------------------------------------
void ofApp::mouseEntered(int x, int y){
    

}

//--------------------------------------------------------------
void ofApp::mouseExited(int x, int y){
    

}

//--------------------------------------------------------------
void ofApp::windowResized(int w, int h){
    

}

//--------------------------------------------------------------
void ofApp::gotMessage(ofMessage msg){

}

//--------------------------------------------------------------
void ofApp::dragEvent(ofDragInfo dragInfo){ 

}

ofApp.h

#pragma once

#include "ofMain.h"

class ofApp : public ofBaseApp{
   
    
	public:
		void setup();
		void update();
    
		void draw();

		void keyPressed(int key);
		void keyReleased(int key);
		void mouseMoved(int x, int y );
		void mouseDragged(int x, int y, int button);
		void mousePressed(int x, int y, int button);
		void mouseReleased(int x, int y, int button);
		void mouseEntered(int x, int y);
		void mouseExited(int x, int y);
		void windowResized(int w, int h);
		void dragEvent(ofDragInfo dragInfo);
		void gotMessage(ofMessage msg);
   private:
    void change(ofQuaternion q1);
    void setquat(unsigned char teapotPacket[14]);
    
    ofQuaternion quat;
    ofQuaternion oldquat;
    ofSerial  serial;
    ofEasyCam cam;
    ofNode mpuNode;
    unsigned char receivedData[14];
    
};

Arduino.ino

// I2C device class (I2Cdev) demonstration Arduino sketch for MPU6050 class using DMP (MotionApps v2.0)
// 6/21/2012 by Jeff Rowberg <jeff@rowberg.net>
// 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.
===============================================
*/

// I2Cdev and MPU6050 must be installed as libraries, or else the .cpp/.h files
// for both classes must be in the include path of your project
#include "I2Cdev.h"

#include "MPU6050_6Axis_MotionApps20.h"
//#include "MPU6050.h" // not necessary if using MotionApps include file

// 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

// 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.
 * ========================================================================= */

/* =========================================================================
   NOTE: Arduino v1.0.1 with the Leonardo board generates a compile error
   when using Serial.write(buf, len). The Teapot output uses this method.
   The solution requires a modification to the Arduino USBAPI.h file, which
   is fortunately simple, but annoying. This will be fixed in the next IDE
   release. For more info, see these links:

   http://arduino.cc/forum/index.php/topic,109987.0.html
   http://code.google.com/p/arduino/issues/detail?id=958
 * ========================================================================= */



// 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)
//#define OUTPUT_READABLE_QUATERNION

// 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
// http://en.wikipedia.org/wiki/Gimbal_lock)
//#define OUTPUT_READABLE_EULER

// 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: http://en.wikipedia.org/wiki/Gimbal_lock)
//#define OUTPUT_READABLE_YAWPITCHROLL

// 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

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


#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
double mpupos[3];
// packet structure for InvenSense teapot demo
uint8_t teapotPacket[14] = { '$', 2, 0,0, 0,0, 0,0, 0,0, 0x00, 0x00, '\r', '\n' };
float teaportPacket[4];
int m;


// ================================================================
// ===               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)
    #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);
    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.

    // initialize device
    //Serial.println(F("Initializing I2C devices..."));
    mpu.initialize();

    // 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

    // load and configure the DMP
    //Serial.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) {
        // turn on the DMP, now that it's ready
        //Serial.println(F("Enabling DMP..."));
        mpu.setDMPEnabled(true);

        // enable Arduino interrupt detection
        //Serial.println(F("Enabling interrupt detection (Arduino external interrupt 0)..."));
        attachInterrupt(0, 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(")"));
    }

    // 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
        mpu.resetFIFO();
        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;

        #ifdef OUTPUT_READABLE_QUATERNION
            // display quaternion values in easy matrix form: w x y z
            mpu.dmpGetQuaternion(&q, fifoBuffer);
            //Serial.write((unsigned char*)teapotPacket, 14);
            if (Serial.available() > 0&&Serial.read()=='r')  m=1;


          
            if(m){
            Serial.write('$');
            Serial.write(2);
            //Serial.print("quat\t");
            //Serial.print("\t");
            
            memcpy(&teapotPacket[0],&q.w,4);
            Serial.write((unsigned char*)teapotPacket,4);
            //Serial.print("\t");
            //Serial.print(q.w);
            //Serial.print(q.x);
            //Serial.print(q.y);
            //Serial.print(q.z);
            memcpy(&teapotPacket[0],&q.x,4);
            Serial.write((unsigned char*)teapotPacket,4);
            memcpy(&teapotPacket[0],&q.y,4);
            Serial.write((unsigned char*)teapotPacket,4);
            memcpy(&teapotPacket[0],&q.z,4);
            Serial.write((unsigned char*)teapotPacket,4);
            
            Serial.write('\r');
            Serial.write('\n');
            m=0;
            }
        #endif

        #ifdef OUTPUT_READABLE_EULER
            // display Euler angles in degrees
            mpu.dmpGetQuaternion(&q, fifoBuffer);
            mpu.dmpGetEuler(euler, &q);
            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

        #ifdef OUTPUT_READABLE_YAWPITCHROLL
            // display Euler angles in degrees
            mpu.dmpGetQuaternion(&q, fifoBuffer);
            mpu.dmpGetGravity(&gravity, &q);
            mpu.dmpGetYawPitchRoll(ypr, &q, &gravity);
              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);
            mpupos[0] = ypr[0] * 180/M_PI;
            mpupos[1] = ypr[1] * 180/M_PI;
            mpupos[2] = ypr[2] * 180/M_PI;
            // if (Serial.available()) {
            Serial.write((unsigned char*)mpupos, 24);
           //wo }
        #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);
            Serial.print("areal\t");
            Serial.print(aaReal.x);
            Serial.print("\t");
            Serial.print(aaReal.y);
            Serial.print("\t");
            Serial.println(aaReal.z);
        #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);
            Serial.print("aworld\t");
            Serial.print(aaWorld.x);
            Serial.print("\t");
            Serial.print(aaWorld.y);
            Serial.print("\t");
            Serial.println(aaWorld.z);
        #endif
    
        #ifdef OUTPUT_TEAPOT
            // display quaternion values in InvenSense Teapot demo format:
             if (Serial.available() > 0&&Serial.read()=='r')  m=1;


          
            if(m){
            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((unsigned char*)teapotPacket, 14);
            teapotPacket[11]++; // packetCount, loops at 0xFF on purpose
            m=0;
            }
        #endif

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

The cube I draw in the OF now can rotate very smoothly, though it will have some offsets on rotation after several secs. Yet, it is the very very first step to be successful. The code is open to everyone who needs it. If one who has a good idea on this topic, don’t be hesitated to share here. By the way, so many thanks to@ roymacdonald, I can hardly figure out ofSerial before ur code! (However, i still use ofSerial in my code, I will try ofxSerial later if time permits. Cheeeeeeeeerrrs!!!)