Artificial Horizon and Compass Using Arduino-Processing-MPU6050

Hi everyone,

Today we will realize our artificial horizon using Arduino, Processing and MPU 6050 IMU.

In this application I use Arduino Uno, If you should use different card, you should examine i2c communication for your card.

For Arduino Uno connections will be like that:

MPU6050 Pins     Arduino Uno Pins

Vcc                        3.3V
Gnd                       Gnd
SCL                       A5
SDA                      A4
INT                       2 (Digital Pin)

This my MPU6050, if you want more information about it:

http://www.invensense.com/mems/gyro/documents/PS-MPU-6000A-00v3.4.pdf

After it we connecting the MPU6050 to Arduino.

If our Arduino-MPU6050 system is ready, we can begin to try it. In this level, we should read three dimensional degrees which are Phi, Theta, Psi on MPU6050 using serial monitor.

For doing this of course we need the code,

Here is the arduino code:

// M.Furkan Bahat , November 2014
// For more information  http://mfurkanbahat.blogspot.com.tr/

#include "I2Cdev.h"
#include "MPU6050_6Axis_MotionApps20.h"

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

MPU6050 mpu;
#define OUTPUT_READABLE_YAWPITCHROLL
#define LED_PIN 13 
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

// packet structure for InvenSense teapot demo
uint8_t teapotPacket[14] = { '$', 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)
    #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
    mpu.initialize();
    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) {
        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 {
        
        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) {
 
    }

    // 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.print("quat\t");
            Serial.print(q.w);
            Serial.print("\t");
            Serial.print(q.x);
            Serial.print("\t");
            Serial.print(q.y);
            Serial.print("\t");
            Serial.println(q.z);
        #endif

        #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("Phi: ");
            Serial.print(ypr[2] * 18/M_PI);
            //Serial.print("\t theta: ");
            Serial.print(" ");
            Serial.print(ypr[1] * 180/M_PI);
            //Serial.print("\t Psi: ");
            Serial.print(" ");
            Serial.println(ypr[0] * 180/M_PI);
            //delay(100);
        #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:
            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
        #endif

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

If there is a problem with compiling the code you can need MPU and i2c library.

You can find in here :

http://playground.arduino.cc/Main/MPU-6050

Everything is Ok ?

Let's going on.

On this level we will use Adrian Fernandez's code. Of course with various fixes.

For these fixes I have focused on Arduino-MPU6050 communication. You can examine Serial event part of code.

Here is the Processing code:

//Thanks to Adrian Fernandez
//Communication updates by M.Furkan Bahat November 2014
//For more information http://mfurkanbahat.blogspot.com.tr/

import processing.serial.*;
import cc.arduino.*;

int W=1400; //My Laptop's screen width 
int H=700;  //My Laptop's screen height 
float Pitch; 
float Bank; 
float Azimuth; 
float ArtificialHoizonMagnificationFactor=0.7; 
float CompassMagnificationFactor=0.85; 
float SpanAngle=120; 
int NumberOfScaleMajorDivisions; 
int NumberOfScaleMinorDivisions; 
PVector v1, v2; 


Serial port;
float Phi;    //Dimensional axis
float Theta;
float Psi;

void setup() 
{ 
  size(W, H); 
  rectMode(CENTER); 
  smooth(); 
  strokeCap(SQUARE);//Optional 
  
  println(Serial.list()); //Shows your connected serial ports
  port = new Serial(this, Serial.list()[0], 115200); 
  //Up there you should select port which arduino connected and same baud rate.
  port.bufferUntil('\n'); 
}
void draw() 
{ 
  background(0); 
  translate(W/4, H/2.1);  
  MakeAnglesDependentOnMPU6050(); 
  Horizon(); 
  rotate(-Bank); 
  PitchScale(); 
  Axis(); 
  rotate(Bank); 
  Borders(); 
  Plane(); 
  ShowAngles(); 
  Compass(); 
  ShowAzimuth(); 
}
void serialEvent(Serial port) //Reading the datas by Processing.
{
   String input = port.readStringUntil('\n');
  if(input != null){
   input = trim(input);
  String[] values = split(input, " ");
 if(values.length == 3){
  float phi = float(values[0]);
  float theta = float(values[1]); 
  float psi = float(values[2]); 
  print(phi);
  print(theta);
  println(psi);
  Phi = phi;
  Theta = theta;
  Psi = psi;
   }
  }
}
void MakeAnglesDependentOnMPU6050() 
{ 
  Bank =-Phi/5; 
  Pitch=Theta*10; 
  Azimuth=Psi;
}
void Horizon() 
{ 
  scale(ArtificialHoizonMagnificationFactor); 
  noStroke(); 
  fill(0, 180, 255); 
  rect(0, -100, 900, 1000); 
  fill(95, 55, 40); 
  rotate(-Bank); 
  rect(0, 400+Pitch, 900, 800); 
  rotate(Bank); 
  rotate(-PI-PI/6); 
  SpanAngle=120; 
  NumberOfScaleMajorDivisions=12; 
  NumberOfScaleMinorDivisions=24;  
  CircularScale(); 
  rotate(PI+PI/6); 
  rotate(-PI/6);  
  CircularScale(); 
  rotate(PI/6); 
}
void ShowAzimuth() 
{ 
  fill(50); 
  noStroke(); 
  rect(20, 470, 440, 50); 
  int Azimuth1=round(Azimuth); 
  textAlign(CORNER); 
  textSize(35); 
  fill(255); 
  text("Azimuth:  "+Azimuth1+" Deg", 80, 477, 500, 60); 
  textSize(40);
  fill(25,25,150);
  text("M.Furkan Bahat", -350, 477, 500, 60); 
}
void Compass() 
{ 
  translate(2*W/3, 0); 
  scale(CompassMagnificationFactor); 
  noFill(); 
  stroke(100); 
  strokeWeight(80); 
  ellipse(0, 0, 750, 750); 
  strokeWeight(50); 
  stroke(50); 
  fill(0, 0, 40); 
  ellipse(0, 0, 610, 610); 
  for (int k=255;k>0;k=k-5) 
  { 
    noStroke(); 
    fill(0, 0, 255-k); 
    ellipse(0, 0, 2*k, 2*k); 
  } 
  strokeWeight(20); 
  NumberOfScaleMajorDivisions=18; 
  NumberOfScaleMinorDivisions=36;  
  SpanAngle=180; 
  CircularScale(); 
  rotate(PI); 
  SpanAngle=180; 
  CircularScale(); 
  rotate(-PI); 
  fill(255); 
  textSize(60); 
  textAlign(CENTER); 
  text("W", -375, 0, 100, 80); 
  text("E", 370, 0, 100, 80); 
  text("N", 0, -365, 100, 80); 
  text("S", 0, 375, 100, 80); 
  textSize(30); 
  text("COMPASS", 0, -130, 500, 80); 
  rotate(PI/4); 
  textSize(40); 
  text("NW", -370, 0, 100, 50); 
  text("SE", 365, 0, 100, 50); 
  text("NE", 0, -355, 100, 50); 
  text("SW", 0, 365, 100, 50); 
  rotate(-PI/4); 
  CompassPointer(); 
}
void CompassPointer() 
{ 
  rotate(PI+radians(Azimuth));  
  stroke(0); 
  strokeWeight(4); 
  fill(100, 255, 100); 
  triangle(-20, -210, 20, -210, 0, 270); 
  triangle(-15, 210, 15, 210, 0, 270); 
  ellipse(0, 0, 45, 45);   
  fill(0, 0, 50); 
  noStroke(); 
  ellipse(0, 0, 10, 10); 
  triangle(-20, -213, 20, -213, 0, -190); 
  triangle(-15, -215, 15, -215, 0, -200); 
  rotate(-PI-radians(Azimuth)); 
}
void Plane() 
{ 
  fill(0); 
  strokeWeight(1); 
  stroke(0, 255, 0); 
  triangle(-20, 0, 20, 0, 0, 25); 
  rect(110, 0, 140, 20); 
  rect(-110, 0, 140, 20); 
}
void CircularScale() 
{ 
  float GaugeWidth=800;  
  textSize(GaugeWidth/30); 
  float StrokeWidth=1; 
  float an; 
  float DivxPhasorCloser; 
  float DivxPhasorDistal; 
  float DivyPhasorCloser; 
  float DivyPhasorDistal; 
  strokeWeight(2*StrokeWidth); 
  stroke(255);
  float DivCloserPhasorLenght=GaugeWidth/2-GaugeWidth/9-StrokeWidth; 
  float DivDistalPhasorLenght=GaugeWidth/2-GaugeWidth/7.5-StrokeWidth;
  for (int Division=0;Division<NumberOfScaleMinorDivisions+1;Division++) 
  { 
    an=SpanAngle/2+Division*SpanAngle/NumberOfScaleMinorDivisions;  
    DivxPhasorCloser=DivCloserPhasorLenght*cos(radians(an)); 
    DivxPhasorDistal=DivDistalPhasorLenght*cos(radians(an)); 
    DivyPhasorCloser=DivCloserPhasorLenght*sin(radians(an)); 
    DivyPhasorDistal=DivDistalPhasorLenght*sin(radians(an));   
    line(DivxPhasorCloser, DivyPhasorCloser, DivxPhasorDistal, DivyPhasorDistal); 
  }
  DivCloserPhasorLenght=GaugeWidth/2-GaugeWidth/10-StrokeWidth; 
  DivDistalPhasorLenght=GaugeWidth/2-GaugeWidth/7.4-StrokeWidth;
  for (int Division=0;Division<NumberOfScaleMajorDivisions+1;Division++) 
  { 
    an=SpanAngle/2+Division*SpanAngle/NumberOfScaleMajorDivisions;  
    DivxPhasorCloser=DivCloserPhasorLenght*cos(radians(an)); 
    DivxPhasorDistal=DivDistalPhasorLenght*cos(radians(an)); 
    DivyPhasorCloser=DivCloserPhasorLenght*sin(radians(an)); 
    DivyPhasorDistal=DivDistalPhasorLenght*sin(radians(an)); 
    if (Division==NumberOfScaleMajorDivisions/2|Division==0|Division==NumberOfScaleMajorDivisions) 
    { 
      strokeWeight(15); 
      stroke(0); 
      line(DivxPhasorCloser, DivyPhasorCloser, DivxPhasorDistal, DivyPhasorDistal); 
      strokeWeight(8); 
      stroke(100, 255, 100); 
      line(DivxPhasorCloser, DivyPhasorCloser, DivxPhasorDistal, DivyPhasorDistal); 
    } 
    else 
    { 
      strokeWeight(3); 
      stroke(255); 
      line(DivxPhasorCloser, DivyPhasorCloser, DivxPhasorDistal, DivyPhasorDistal); 
    } 
  } 
}
void Axis() 
{ 
  stroke(255, 0, 0); 
  strokeWeight(3); 
  line(-115, 0, 115, 0); 
  line(0, 280, 0, -280); 
  fill(100, 255, 100); 
  stroke(0); 
  triangle(0, -285, -10, -255, 10, -255); 
  triangle(0, 285, -10, 255, 10, 255); 
}
void ShowAngles() 
{ 
  textSize(30); 
  fill(50); 
  noStroke(); 
  rect(-150, 400, 280, 40); 
  rect(150, 400, 280, 40); 
  fill(255); 
  Pitch=Pitch/5; 
  int Pitch1=round(Pitch);  
  text("Pitch:  "+Pitch1+" Deg", -20, 411, 500, 60); 
  text("Bank:  "+Bank*100+" Deg", 280, 411, 500, 60); 
}
void Borders() 
{ 
  noFill(); 
  stroke(0); 
  strokeWeight(400); 
  rect(0, 0, 1100, 1100); 
  strokeWeight(200); 
  ellipse(0, 0, 1000, 1000); 
  fill(0); 
  noStroke(); 
  rect(4*W/5, 0, W, 2*H); 
  rect(-4*W/5, 0, W, 2*H); 
}
void PitchScale() 
{  
  stroke(255); 
  fill(255); 
  strokeWeight(3); 
  textSize(24); 
  textAlign(CENTER); 
  for (int i=-4;i<5;i++) 
  {  
    if ((i==0)==false) 
    { 
      line(110, 50*i, -110, 50*i); 
    }  
    text(""+i*10, 140, 50*i, 100, 30); 
    text(""+i*10, -140, 50*i, 100, 30); 
  } 
  textAlign(CORNER); 
  strokeWeight(2); 
  for (int i=-9;i<10;i++) 
  {  
    if ((i==0)==false) 
    {    
      line(25, 25*i, -25, 25*i); 
    } 
  } 
}

Let's watch, what is happening ?