Diff: main.cpp

Revision:

0:07431908151a

Child:

3:9424c6493a75

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+++ b/main.cpp	Tue Sep 05 04:34:29 2017 +0000
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+
+/* MPU6050 Basic Example Code
+ by: Kris Winer
+ date: May 1, 2014
+ license: Beerware - Use this code however you'd like. If you 
+ find it useful you can buy me a beer some time.
+ 
+ Demonstrate  MPU-6050 basic functionality including initialization, accelerometer trimming, sleep mode functionality as well as
+ parameterizing the register addresses. Added display functions to allow display to on breadboard monitor. 
+ No DMP use. We just want to get out the accelerations, temperature, and gyro readings.
+ 
+ SDA and SCL should have external pull-up resistors (to 3.3V).
+ 10k resistors worked for me. They should be on the breakout
+ board.
+ 
+ Hardware setup:
+ MPU6050 Breakout --------- Arduino
+ 3.3V --------------------- 3.3V
+ SDA ----------------------- A4
+ SCL ----------------------- A5
+ GND ---------------------- GND
+ 
+  Note: The MPU6050 is an I2C sensor and uses the Arduino Wire library. 
+ Because the sensor is not 5V tolerant, we are using a 3.3 V 8 MHz Pro Mini or a 3.3 V Teensy 3.1.
+ We have disabled the internal pull-ups used by the Wire library in the Wire.h/twi.c utility file.
+ We are also using the 400 kHz fast I2C mode by setting the TWI_FREQ  to 400000L /twi.h utility file.
+ */
+ 
+#include "mbed.h"
+#include "MPU6050.h"
+
+float sum = 0;
+uint32_t sumCount = 0;
+
+   MPU6050 mpu6050;
+   
+   Timer t;
+        
+int main()
+{
+  //Set up I2C
+  i2c.frequency(400000);  // use fast (400 kHz) I2C   
+  
+  t.start(); 
+    
+  // Read the WHO_AM_I register, this is a good test of communication
+  uint8_t whoami = mpu6050.readByte(MPU6050_ADDRESS, WHO_AM_I_MPU6050);  // Read WHO_AM_I register for MPU-6050
+  //pc.printf("I AM 0x%x\n\r", whoami); pc.printf("I SHOULD BE 0x68\n\r");
+  
+  if (whoami == 0x68) // WHO_AM_I should always be 0x68
+  {  
+    wait(1);
+    
+    mpu6050.MPU6050SelfTest(SelfTest); // Start by performing self test and reporting values
+    /*
+    pc.printf("x-axis self test: acceleration trim within : "); pc.printf("%f", SelfTest[0]); pc.printf("% of factory value \n\r");
+    pc.printf("y-axis self test: acceleration trim within : "); pc.printf("%f", SelfTest[1]); pc.printf("% of factory value \n\r");
+    pc.printf("z-axis self test: acceleration trim within : "); pc.printf("%f", SelfTest[2]); pc.printf("% of factory value \n\r");
+    pc.printf("x-axis self test: gyration trim within : "); pc.printf("%f", SelfTest[3]); pc.printf("% of factory value \n\r");
+    pc.printf("y-axis self test: gyration trim within : "); pc.printf("%f", SelfTest[4]); pc.printf("% of factory value \n\r");
+    pc.printf("z-axis self test: gyration trim within : "); pc.printf("%f", SelfTest[5]); pc.printf("% of factory value \n\r");
+    */
+    wait(1);
+
+    if(SelfTest[0] < 1.0f && SelfTest[1] < 1.0f && SelfTest[2] < 1.0f && SelfTest[3] < 1.0f && SelfTest[4] < 1.0f && SelfTest[5] < 1.0f) 
+    {
+    mpu6050.resetMPU6050(); // Reset registers to default in preparation for device calibration
+    mpu6050.calibrateMPU6050(gyroBias, accelBias); // Calibrate gyro and accelerometers, load biases in bias registers  
+    mpu6050.initMPU6050(); pc.printf("MPU6050 initialized for active data mode....\n\r"); // Initialize device for active mode read of acclerometer, gyroscope, and temperature
+
+    wait(2);
+       }
+    else
+    {
+    /*
+    pc.printf("Device did not the pass self-test!\n\r");
+ 
+       lcd.clear();
+       lcd.printString("MPU6050", 0, 0);
+       lcd.printString("no pass", 0, 1);
+       lcd.printString("self test", 0, 2);      */
+      }
+    }
+    else
+    {
+    /*pc.printf("Could not connect to MPU6050: \n\r");
+    pc.printf("%#x \n",  whoami);
+ 
+    lcd.clear();
+    lcd.printString("MPU6050", 0, 0);
+    lcd.printString("no connection", 0, 1);
+    lcd.printString("0x", 0, 2);  lcd.setXYAddress(20, 2); lcd.printChar(whoami);
+ */
+ 
+    while(1) ; // Loop forever if communication doesn't happen
+  }
+
+
+
+ while(1) {
+  
+  // If data ready bit set, all data registers have new data
+  if(mpu6050.readByte(MPU6050_ADDRESS, INT_STATUS) & 0x01) {  // check if data ready interrupt
+    mpu6050.readAccelData(accelCount);  // Read the x/y/z adc values
+    mpu6050.getAres();
+    
+    // Now we'll calculate the accleration value into actual g's
+    ax = (float)accelCount[0]*aRes - accelBias[0];  // get actual g value, this depends on scale being set
+    ay = (float)accelCount[1]*aRes - accelBias[1];   
+    az = (float)accelCount[2]*aRes - accelBias[2];  
+   
+    mpu6050.readGyroData(gyroCount);  // Read the x/y/z adc values
+    mpu6050.getGres();
+ 
+    // Calculate the gyro value into actual degrees per second
+    gx = (float)gyroCount[0]*gRes; // - gyroBias[0];  // get actual gyro value, this depends on scale being set
+    gy = (float)gyroCount[1]*gRes; // - gyroBias[1];  
+    gz = (float)gyroCount[2]*gRes; // - gyroBias[2];   
+
+    tempCount = mpu6050.readTempData();  // Read the x/y/z adc values
+    temperature = (tempCount) / 340. + 36.53; // Temperature in degrees Centigrade
+   }  
+   
+    Now = t.read_us();
+    deltat = (float)((Now - lastUpdate)/1000000.0f) ; // set integration time by time elapsed since last filter update
+    lastUpdate = Now;
+    
+    sum += deltat;
+    sumCount++;
+    
+    if(lastUpdate - firstUpdate > 10000000.0f) {
+     beta = 0.04;  // decrease filter gain after stabilized
+     zeta = 0.015; // increasey bias drift gain after stabilized
+    }
+    
+   // Pass gyro rate as rad/s
+    mpu6050.MadgwickQuaternionUpdate(ax, ay, az, gx*PI/180.0f, gy*PI/180.0f, gz*PI/180.0f);
+
+    // Serial print and/or display at 0.5 s rate independent of data rates
+    delt_t = t.read_ms() - count;
+    if (delt_t > 500) { // update LCD once per half-second independent of read rate
+
+    /*
+    pc.printf("ax = %f", 1000*ax); 
+    pc.printf(" ay = %f", 1000*ay); 
+    pc.printf(" az = %f  mg\n\r", 1000*az); 
+
+    pc.printf("gx = %f", gx); 
+    pc.printf(" gy = %f", gy); 
+    pc.printf(" gz = %f  deg/s\n\r", gz); 
+    
+    pc.printf(" temperature = %f  C\n\r", temperature); 
+    
+    pc.printf("q0 = %f\n\r", q[0]);
+    pc.printf("q1 = %f\n\r", q[1]);
+    pc.printf("q2 = %f\n\r", q[2]);
+    pc.printf("q3 = %f\n\r", q[3]);      
+    
+    lcd.clear();
+    lcd.printString("MPU6050", 0, 0);
+    lcd.printString("x   y   z", 0, 1);
+    lcd.setXYAddress(0, 2); lcd.printChar((char)(1000*ax));
+    lcd.setXYAddress(20, 2); lcd.printChar((char)(1000*ay));
+    lcd.setXYAddress(40, 2); lcd.printChar((char)(1000*az)); lcd.printString("mg", 66, 2);
+    */
+    
+    
+  // Define output variables from updated quaternion---these are Tait-Bryan angles, commonly used in aircraft orientation.
+  // In this coordinate system, the positive z-axis is down toward Earth. 
+  // Yaw is the angle between Sensor x-axis and Earth magnetic North (or true North if corrected for local declination, looking down on the sensor positive yaw is counterclockwise.
+  // Pitch is angle between sensor x-axis and Earth ground plane, toward the Earth is positive, up toward the sky is negative.
+  // Roll is angle between sensor y-axis and Earth ground plane, y-axis up is positive roll.
+  // These arise from the definition of the homogeneous rotation matrix constructed from quaternions.
+  // Tait-Bryan angles as well as Euler angles are non-commutative; that is, the get the correct orientation the rotations must be
+  // applied in the correct order which for this configuration is yaw, pitch, and then roll.
+  // For more see http://en.wikipedia.org/wiki/Conversion_between_quaternions_and_Euler_angles which has additional links.
+    yaw   = atan2(2.0f * (q[1] * q[2] + q[0] * q[3]), q[0] * q[0] + q[1] * q[1] - q[2] * q[2] - q[3] * q[3]);   
+    pitch = -asin(2.0f * (q[1] * q[3] - q[0] * q[2]));
+    roll  = atan2(2.0f * (q[0] * q[1] + q[2] * q[3]), q[0] * q[0] - q[1] * q[1] - q[2] * q[2] + q[3] * q[3]);
+    pitch *= 180.0f / PI;
+    yaw   *= 180.0f / PI; 
+    roll  *= 180.0f / PI;
+
+//    pc.printf("Yaw, Pitch, Roll: \n\r");
+//    pc.printf("%f", yaw);
+//    pc.printf(", ");
+//    pc.printf("%f", pitch);
+//    pc.printf(", ");
+//    pc.printf("%f\n\r", roll);
+//    pc.printf("average rate = "); pc.printf("%f", (sumCount/sum)); pc.printf(" Hz\n\r");
+
+     //pc.printf("Yaw, Pitch, Roll: %f %f %f\n\r", yaw, pitch, roll);
+     //pc.printf("average rate = %f\n\r", (float) sumCount/sum);
+ 
+    //myled= !myled;
+    count = t.read_ms(); 
+    sum = 0;
+    sumCount = 0; 
+}
+}
+ 
+ }
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