I am currently trying to write (obtain) a code for getting raw acceleration values and yaw, pitch and roll angles using these Jeff Rowberg's examples. I have used MPU6050_DMP example to get this code:
// 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 // 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 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; } int16_t ax, ay, az, axd, ayd, azd, axo=0, ayo=0, azo=0; // ================================================================ // === INITIAL SETUP === // ================================================================ void 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(38400); 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 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(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 === // ================================================================ uint16_t lv = 1; 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) { } mpu.getAcceleration(&ax, &ay, &az); // 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; // 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.print(ypr[2] * 180/M_PI); Serial.print("\t"); Serial.print("ax "); Serial.print(ax); Serial.print("\t"); Serial.print("ay "); Serial.print(ay); Serial.print("\t"); Serial.print("az "); Serial.println(az); // blink LED to indicate activity blinkState = !blinkState; digitalWrite(LED_PIN, blinkState); } if(lv < 501) ++lv; else { lv = 1; digitalWrite(13, !digitalRead(13)); } } However when this code, run at 38400 or 1920 baud rate, gives the least frequent FIFO overflow errors (sometimes at 38400, otherwise at 19200). If this code is run below this "optimal" baud rate, FIFO overflow frequency increases. If thic code is run at above "optimal" baud rate, the board freezes after about 10 seconds (always, in every case), the TX just stops binking. Any suggested solution? Board : Arduino Uno, being used with MPU6050
