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Arek's Achievements


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  1. Hello, I'm encountering problem with function given in the title of this thread. My project is based on angular velocity from the Mpu6050's gyro, but I don't seem to get smooth enough readings. What is happening: - Through first 5-10s after the power up I mostly (not always) get perfect 0.00 reading. - After the internal calibration process ends, output gets dominated by -1.00 reading mixed with the prevoius one. (so it goes radomly like: -1-1-1-10-1000-10-10-1-10...and so on). In this case I can't simply compensate the reading by adding a constant. Is there a way to smooth output value? Also, it prints with the decimals, but it doesn't use them(X.00). How to get better precision with decimals being involved(eg. X.34)? And lastly, just to make sure, are those readings given in deg/s? Why I'm not using only gyro module? Because I'll need precise angle in later development to implement cascade PID. What I have tried/done: - Changing offsets. Result: it only changes output val for those first seconds. After, as I guess, internal calibration process it always ends on reading -1 and 0's. - No external noise is involved(from motors etc.) and MPU (Gy-521) doesn't share power supply with any other device. Conection( MPU - Arduino uno): Vcc - 5v Gnd- Gnd Sda - Sda Scl - Scl AD0- 5v // only with this setup I'm avoiding random sketch hangs... so far. Int - D2 I've modified / shortened Jeff's code (I'm using multiple tab sketch). I'll be grateful for any help. Also, I want to thank you for all the information I could find on this forum. Regards, Arek // 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 * ========================================================================= */ #define OUTPUT_READABLE_YAWPITCHROLL #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 VectorFloat gravity; // [x, y, z] gravity vector float ypr[3]; // [yaw, pitch, roll] yaw/pitch/roll container and gravity vector int16_t gyro[3]; //[x,y,z] // ================================================================ // === INTERRUPT DETECTION ROUTINE === // ================================================================ volatile bool mpuInterrupt = false; // indicates whether MPU interrupt pin has gone high void dmpDataReady() { mpuInterrupt = true; } // ================================================================ // === INITIAL SETUP === // ================================================================ bool MPU_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). Comment this line if having compilation difficulties with TWBR. #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) 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(); mpu.setFullScaleGyroRange(0); //set the gyro range to 250 mpu.setFullScaleAccelRange(0); //set the accelerometer sensibilty to 2g Serial.print(F("Gyro sensitivity: ")); Serial.println(mpu.getFullScaleGyroRange()); // print gyro / acc sensitivity Serial.print(F("Acc sensitivity: ")); Serial.println(mpu.getFullScaleAccelRange()); // verify connection Serial.println(F("Testing device connections...")); Serial.println(mpu.testConnection() ? F("MPU6050 connection successful") : F("MPU6050 connection failed")); // 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(-30); mpu.setYGyroOffset(-54); mpu.setZGyroOffset(-21); mpu.setXAccelOffset(-3083); mpu.setYAccelOffset(-1972); mpu.setZAccelOffset(754); // 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(")")); return false; } // configure LED for output pinMode(LED_PIN, OUTPUT); return true; } // ================================================================ // === MAIN PROGRAM LOOP === // ================================================================ void MPU_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_YAWPITCHROLL // display Euler angles in degrees & angular velocity from gyro mpu.dmpGetQuaternion(&q, fifoBuffer); mpu.dmpGetGyro(gyro, fifoBuffer); mpu.dmpGetGravity(&gravity, &q); mpu.dmpGetYawPitchRoll(ypr, &q, &gravity); #endif // blink LED to indicate activity blinkState = !blinkState; digitalWrite(LED_PIN, blinkState); } } double MPU_gyroX(){ return gyro[0]; }
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