SMARS Demo program

lesson_01_movement.ino

// Lesson 01 Movement
// www.smarsfan.com/play/lessons/lesson_01_movement

// set Motor A to Arduino Pins
int motor_A = 12;
int motor_B = 13;

// set the Motor Speed using the Arduino Pins
int motor_A_speed = 10;
int motor_B_speed = 11;

// set the time between motor on and motor off
int wait_in_milliseconds = 1000;

// this code runs once at the start
void setup() {

  // this sets the speed of communication between the computer and Arduino,
  // used when uploading your code
  Serial.begin(9600);

  // set the Arduino pin to OUTPUT mode
  pinMode(motor_A, OUTPUT);
  pinMode(motor_B, OUTPUT);
}

// move forward
void forward() {

  // set the direction to forward
  digitalWrite(motor_A, HIGH);
  digitalWrite(motor_B, LOW);

  // set to full speed
  analogWrite(motor_A_speed, 255);
  analogWrite(motor_B_speed, 255);

  // wait
  delay(wait_in_milliseconds);

  // stop
  analogWrite(motor_A_speed, 0);
  analogWrite(motor_B_speed, 0);
}

// the main program loop
void loop(){

  // move forward
  forward();

  // wait 2 seconds
  delay(2000);
}

lesson_02_turning.ino

// Lesson 02 Turning
// www.smarsfan.com/play/lessons/lesson_02_turning

// set Motor A to Arduino Pins
int motor_A = 12;
int motor_B = 13;

// set the Motor Speed using the Arduino Pins
int motor_A_speed = 10;
int motor_B_speed = 11;

// set the time between motor on and motor off
int wait_in_milliseconds = 1000;

// this code runs once at the start
void setup() {

  // this sets the speed of communication between the computer and Arduino,
  // used when uploading your code
  Serial.begin(9600);

  Serial.println("SMARS OS v1.0")
  // set the Arduino pin to OUTPUT mode
  pinMode(motor_A, OUTPUT);
  pinMode(motor_B, OUTPUT);
}

// move forward
void forward() {

  // set the direction to forward
  digitalWrite(motor_A, HIGH);
  digitalWrite(motor_B, LOW);

  // set to full speed
  analogWrite(motor_A_speed, 255);
  analogWrite(motor_B_speed, 255);

  // wait
  delay(wait_in_milliseconds);

  // stop
  analogWrite(motor_A_speed, 0);
  analogWrite(motor_B_speed, 0);
}

// move backward
void backward() {

  // set the direction to backward
  digitalWrite(motor_A, LOW);
  digitalWrite(motor_B, HIGH);

  // set to full speed
  analogWrite(motor_A_speed, 255);
  analogWrite(motor_B_speed, 255);

  // wait
  delay(wait_in_milliseconds);

  // stop
  analogWrite(motor_A_speed, 0);
  analogWrite(motor_B_speed, 0);
}

// turn left
void turnLeft() {

  // set the direction to backward
  digitalWrite(motor_A, HIGH);
  digitalWrite(motor_B, HIGH);

  // set to full speed
  analogWrite(motor_A_speed, 255);
  analogWrite(motor_B_speed, 255);

  // wait
  delay(wait_in_milliseconds);

  // stop
  analogWrite(motor_A_speed, 0);
  analogWrite(motor_B_speed, 0);
}

// turn right
void turnRight() {

  // set the direction to backward
  digitalWrite(motor_A, LOW);
  digitalWrite(motor_B, LOW);

  // set to full speed
  analogWrite(motor_A_speed, 255);
  analogWrite(motor_B_speed, 255);

  // wait
  delay(wait_in_milliseconds);

  // stop
  analogWrite(motor_A_speed, 0);
  analogWrite(motor_B_speed, 0);
}

// the main program loop
void loop(){

  while (Serial.available()) {
    char c = Serial.read();
    switch(c) {
    // press the 'w' key to move SMARS Forward
    case 'w':
    Serial.println("Moving Forward");
    forward();
    break;

    // press the 's' key to move SMARS backward
    case 's':
    Serial.println("Moving Backward");
    backward();
    break;

    // press the 'a' key to move SMARS left
    case 'a':
    Serial.println("Turning Left");
    turnLeft();
    break;

    // press the 'd' key to move SMARS right
    case 'd':
    Serial.println("Turning Right");
    turnRight();
    break;
    }
  }
  // wait 2 seconds
  delay(2000);
}

lesson_03_avoid.ino

// Lesson 03 Sensors - Avoid Obstacles
// www.smarsfan.com/play/lessons/lesson_03_sensors

// set Motor A to Arduino Pins
int motor_A = 12;
int motor_B = 13;

// set the Motor Speed using the Arduino Pins
int motor_A_speed = 10;
int motor_B_speed = 11;

// set the time between motor on and motor off
int wait_in_milliseconds = 1000;

// set the Rangefinder pins
#define echoPin 8 
#define trigPin 7  

// set the variables for ping duration and measured distance
long duration;
int distance;

// this code runs once at the start
void setup() {

  // setup the Pin modes for the range finder
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);

  // this sets the speed of communication between the computer and Arduino,
  // used when uploading your code
  Serial.begin(9600);

  Serial.println("SMARS OS v1.0");
  // set the Arduino pin to OUTPUT mode
  pinMode(motor_A, OUTPUT);
  pinMode(motor_B, OUTPUT);
}

// Sends out a ping and measures the distance, and returns it
int ping(){

  // Clears the trigPin condition
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);

  // Sets the trigPin HIGH (ACTIVE) for 10 microseconds
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  // Reads the echoPin, returns the sound wave travel time in microseconds
  duration = pulseIn(echoPin, HIGH);

  // calculate the distance
  distance = duration * 0.034 / 2;
  return distance;
}

// move forward
void forward() {

  // set the direction to forward
  digitalWrite(motor_A, HIGH);
  digitalWrite(motor_B, LOW);

  // set to full speed
  analogWrite(motor_A_speed, 255);
  analogWrite(motor_B_speed, 255);

  // wait
  delay(wait_in_milliseconds);

  // stop
  analogWrite(motor_A_speed, 0);
  analogWrite(motor_B_speed, 0);
}

// move backward
void backward() {

  // set the direction to backward
  digitalWrite(motor_A, LOW);
  digitalWrite(motor_B, HIGH);

  // set to full speed
  analogWrite(motor_A_speed, 255);
  analogWrite(motor_B_speed, 255);

  // wait
  delay(wait_in_milliseconds);

  // stop
  analogWrite(motor_A_speed, 0);
  analogWrite(motor_B_speed, 0);
}

// turn left
void turnLeft() {

  // set the direction to backward
  digitalWrite(motor_A, HIGH);
  digitalWrite(motor_B, HIGH);

  // set to full speed
  analogWrite(motor_A_speed, 255);
  analogWrite(motor_B_speed, 255);

  // wait
  delay(wait_in_milliseconds);

  // stop
  analogWrite(motor_A_speed, 0);
  analogWrite(motor_B_speed, 0);
}

// turn right
void turnRight() {

  // set the direction to backward
  digitalWrite(motor_A, LOW);
  digitalWrite(motor_B, LOW);

  // set to full speed
  analogWrite(motor_A_speed, 255);
  analogWrite(motor_B_speed, 255);

  // wait
  delay(wait_in_milliseconds);

  // stop
  analogWrite(motor_A_speed, 0);
  analogWrite(motor_B_speed, 0);
}

// the main program loop
void loop(){
  while (true) {

   int dist = ping();
   if (dist < 5) {
     turnLeft();
   }
   else {
     forward();
     // wait 
    delay(wait_in_milliseconds);
   }
    
  }
}

lesson_03_range_finder.ino

// Lesson 03 Sensors
// www.smarsfan.com/play/lessons/lesson_03_sensors

// set the Rangefinder pins
#define echoPin 8 
#define trigPin 7  

// set the variables for ping duration and measured distance
long duration;
int distance;

void setup() {
  // put your setup code here, to run once:

  // setup the Pin modes for the range finder
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);

  Serial.begin(9600);
  Serial.println("Ultrasonic Sensor HC-SR07");
  Serial.println("with Arduino UNO R3");
}

void loop() {
  // put your main code here, to run repeatedly:

  // Clears the trigPin condition
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);

  // Sets the trigPin HIGH (ACTIVE) for 10 microseconds
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  // Reads the echoPin, returns the sound wave travel time in microseconds
  duration = pulseIn(echoPin, HIGH);

  // calculate the distance
  distance = duration * 0.034 / 2;

  Serial.print("Distance: ");
  Serial.print(distance);
  Serial.println(" cm");
}

lesson_04_positioning_loop.ino

void loop(){
  float turn_heading;
  while(true) {
    mpu_loop();
    int dist = ping();
    if (dist > 10) {
      forward();
    }
    else 
    {
      Serial.println('OBSTACLE! - Turning left');
      // turn left until 90 degrees from current heading
      
      float heading = get_heading();
      float target_heading = heading;
      
      Serial.print("Heading = ");
      Serial.println(heading);
      while (target_heading <= (heading + 90)) {
        turn_heading = get_heading();
        Serial.print("Heading = ");
        Serial.println(turn_heading);
        turnLeft();
      }
      heading = turn_heading;
    }
  }
}

lesson_04_positioning_motors.ino

// Lesson 03 Sensors - Avoid Obstacles
// www.smarsfan.com/play/lessons/lesson_03_sensors

// set Motor A to Arduino Pins
int motor_A = 12;
int motor_B = 13;

// set the Motor Speed using the Arduino Pins
int motor_A_speed = 10;
int motor_B_speed = 11;

// set the time between motor on and motor off
int wait_in_milliseconds = 1000;

// set the Rangefinder pins
#define echoPin 8 
#define trigPin 7  



// this code runs once at the start
void motor_setup() {

  // setup the Pin modes for the range finder
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);

  // this sets the speed of communication between the computer and Arduino,
  // used when uploading your code
//  Serial.begin(9600);

  Serial.println("Motors - online");
  // set the Arduino pin to OUTPUT mode
  pinMode(motor_A, OUTPUT);
  pinMode(motor_B, OUTPUT);
}



// move forward
void forward() {

  // set the direction to forward
  digitalWrite(motor_A, HIGH);
  digitalWrite(motor_B, LOW);

  // set to full speed
  analogWrite(motor_A_speed, 255);
  analogWrite(motor_B_speed, 255);

  // wait
  delay(wait_in_milliseconds);

  // stop
  analogWrite(motor_A_speed, 0);
  analogWrite(motor_B_speed, 0);
}

// move backward
void backward() {

  // set the direction to backward
  digitalWrite(motor_A, LOW);
  digitalWrite(motor_B, HIGH);

  // set to full speed
  analogWrite(motor_A_speed, 255);
  analogWrite(motor_B_speed, 255);

  // wait
  delay(wait_in_milliseconds);

  // stop
  analogWrite(motor_A_speed, 0);
  analogWrite(motor_B_speed, 0);
}

// turn left
void turnLeft() {

  // set the direction to backward
  digitalWrite(motor_A, HIGH);
  digitalWrite(motor_B, HIGH);

  // set to full speed
  analogWrite(motor_A_speed, 255);
  analogWrite(motor_B_speed, 255);

  // wait
  delay(wait_in_milliseconds);

  // stop
  analogWrite(motor_A_speed, 0);
  analogWrite(motor_B_speed, 0);
}

// turn right
void turnRight() {

  // set the direction to backward
  digitalWrite(motor_A, LOW);
  digitalWrite(motor_B, LOW);

  // set to full speed
  analogWrite(motor_A_speed, 255);
  analogWrite(motor_B_speed, 255);

  // wait
  delay(wait_in_milliseconds);

  // stop
  analogWrite(motor_A_speed, 0);
  analogWrite(motor_B_speed, 0);
}

// the main program loop
void motor_loop(){
  while (true) {

   int dist = ping();
   if (dist < 5) {
     turnLeft();
   }
   else {
     forward();
     // wait 
    delay(wait_in_milliseconds);
   }
    
  }
}

lesson_04_positioning_mpu6050.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:
//      2019-07-08 - Added Auto Calibration and offset generator
//		   - and altered FIFO retrieval sequence to avoid using blocking code
//      2016-04-18 - Eliminated a potential infinite loop
//      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 INTERRUPT_PIN 2  // use pin 2 on Arduino Uno & most boards
#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

// 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 mpu_setup() {
    // join I2C bus (I2Cdev library doesn't do this automatically)
    #if I2CDEV_IMPLEMENTATION == I2CDEV_ARDUINO_WIRE
        Wire.begin();
        Wire.setClock(400000); // 400kHz I2C clock. Comment this line if having compilation difficulties
    #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 Arduino
    // 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();
    pinMode(INTERRUPT_PIN, INPUT);

    // verify connection
    Serial.println(F("Testing device connections..."));
    Serial.println(mpu.testConnection() ? F("MPU6050 - online") : 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) {
        // 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(")"));
    }

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



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

float get_heading(){
  if (mpu.dmpGetCurrentFIFOPacket(fifoBuffer)) {
  mpu.dmpGetQuaternion(&q, fifoBuffer);
  mpu.dmpGetEuler(euler, &q);
  return euler[0] * 180/M_PI;
  }
}


void mpu_loop() {
    // 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_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("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);
        #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);
    }
}

lesson_04_positioning_setup.ino

void setup(){
  range_finder_setup();
  mpu_setup();
  motor_setup();
  int dead_reconing = 0; // straight ahead
}

smars_demo.ino

/*
This is a sketch for the Adafruit assembled Motor Shield for Arduino v2
It won't work with v1.x motor shields! Only for the v2's with built in PWM
control

For use with the Adafruit Motor Shield v2
---->  http://www.adafruit.com/products/1438
*/

#include <Wire.h>
#include <Adafruit_MotorShield.h>

// Create the motor shield object with the default I2C address
Adafruit_MotorShield AFMS = Adafruit_MotorShield();
// Or, create it with a different I2C address (say for stacking)
// Adafruit_MotorShield AFMS = Adafruit_MotorShield(0x61);

// Select which 'port' M1, M2, M3 or M4. In this case, M1 and M2
Adafruit_DCMotor *MotorL = AFMS.getMotor(1);
Adafruit_DCMotor *MotorR = AFMS.getMotor(2);
// You can also make another motor on port M3
//Adafruit_DCMotor *myOtherMotor = AFMS.getMotor(3);

//ultrasonic setup:
 int distancecm=0;
 const int trigPin = 10; // trig pin connected to Arduino's pin 10
 const int echoPin = 11; // echo pin connected to Arduino's pin 11
// defines variables
long duration;
int distance;

void setup() {
  Serial.begin(9600);           // set up Serial library at 9600 bps
  Serial.println("Adafruit Motorshield v2 - DC Motor with ultrasonic sensor!");
  pinMode(trigPin, OUTPUT); // Sets the trigPin as an Output
  pinMode(echoPin, INPUT); // Sets the echoPin as an Input
  AFMS.begin();  // create with the default frequency 1.6KHz
  //AFMS.begin(1000);  // OR with a different frequency, say 1KHz

  // Set the speed to start, from 0 (off) to 255 (max speed)
  // sometimes the motors don't have the same speed, so use these values tomake your SMARS move straight
  MotorL->setSpeed(150);
  MotorR->setSpeed(150);
  MotorL->run(FORWARD);
  MotorR->run(FORWARD);
  // turn on motor
  MotorL->run(RELEASE);
  MotorR->run(RELEASE);
}

// main program loop
void loop() {

 distancecm=mdistance();   //if the distance is less than 5cm, SMARS will go backward for 1 second, and turn right for 1 second
  if(distance<5){
    MotorL->run(BACKWARD);
    MotorR->run(BACKWARD);
    delay(1000);
    MotorL->run(FORWARD);
    MotorR->run(BACKWARD);
    delay(1000);
  }
  else {
    MotorL->run(FORWARD); //otherwise it will continue forward
    MotorR->run(FORWARD);
  }
}

//ultrasonic distance mesurement function
int mdistance() {
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  // Sets the trigPin on HIGH state for 10 micro seconds
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  // Reads the echoPin, returns the sound wave travel time in microseconds
  duration = pulseIn(echoPin, HIGH);
  // Calculating the distance
  distance= duration*0.034/2;
  // Prints the distance on the Serial Monitor
  Serial.print("Distance: ");
}