BE@R lab
Class of MPU9250
Dependencies: AHRS_fillter mbed
Fork of
MPU9250AHRS
by 
BE@R lab
Diff: main.cpp
- Revision:
- 3:3e04c1c03cab
- Parent:
- 1:71c319f03fda
- Child:
- 4:1e5db958fd1b
--- a/main.cpp Tue Aug 05 01:37:23 2014 +0000
+++ b/main.cpp Fri Dec 18 12:59:56 2015 +0000
@@ -1,17 +1,17 @@
/* MPU9250 Basic Example Code
by: Kris Winer
date: April 1, 2014
- license: Beerware - Use this code however you'd like. If you
+ license: Beerware - Use this code however you'd like. If you
find it useful you can buy me a beer some time.
-
- Demonstrate basic MPU-9250 functionality including parameterizing the register addresses, initializing the sensor,
- getting properly scaled accelerometer, gyroscope, and magnetometer data out. Added display functions to
- allow display to on breadboard monitor. Addition of 9 DoF sensor fusion using open source Madgwick and
+
+ Demonstrate basic MPU-9250 functionality including parameterizing the register addresses, initializing the sensor,
+ getting properly scaled accelerometer, gyroscope, and magnetometer data out. Added display functions to
+ allow display to on breadboard monitor. Addition of 9 DoF sensor fusion using open source Madgwick and
Mahony filter algorithms. Sketch runs on the 3.3 V 8 MHz Pro Mini and the Teensy 3.1.
-
+
SDA and SCL should have external pull-up resistors (to 3.3V).
10k resistors are on the EMSENSR-9250 breakout board.
-
+
Hardware setup:
MPU9250 Breakout --------- Arduino
VDD ---------------------- 3.3V
@@ -19,18 +19,18 @@
SDA ----------------------- A4
SCL ----------------------- A5
GND ---------------------- GND
-
- Note: The MPU9250 is an I2C sensor and uses the Arduino Wire library.
+
+ Note: The MPU9250 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 "ST_F401_84MHZ.h"
+
+//#include "ST_F401_84MHZ.h"
//F401_init84 myinit(0);
#include "mbed.h"
#include "MPU9250.h"
-#include "N5110.h"
+//#include "N5110.h"
// Using NOKIA 5110 monochrome 84 x 48 pixel display
// pin 9 - Serial clock out (SCLK)
@@ -44,87 +44,106 @@
uint32_t sumCount = 0;
char buffer[14];
- MPU9250 mpu9250;
-
- Timer t;
+MPU9250 mpu9250;
+
+Timer t;
- Serial pc(USBTX, USBRX); // tx, rx
+Serial pc(USBTX, USBRX); // tx, rx
+
+// VCC, SCE, RST, D/C, MOSI,S CLK, LED
+//N5110 lcd(PA_8, PB_10, PA_9, PA_6, PA_7, PA_5, PC_7);
+float xmax = -4914.0f;
+float xmin = 4914.0f;
- // VCC, SCE, RST, D/C, MOSI,S CLK, LED
- N5110 lcd(PA_8, PB_10, PA_9, PA_6, PA_7, PA_5, PC_7);
-
+float ymax = -4914.0;
+float ymin = 4914.0f;
+
+float zmax = -4914.0;
+float zmin = 4914.0f;
-
+float Xsf,Ysf;
+float Xoff,Yoff;
+
+
+//InterruptIn event(PC_13);
+DigitalIn enable(PC_13);
+
int main()
{
- pc.baud(9600);
+
+ pc.baud(115200);
+
+ //Set up I2C
+ i2c.frequency(400000); // use fast (400 kHz) I2C
- //Set up I2C
- i2c.frequency(400000); // use fast (400 kHz) I2C
-
- pc.printf("CPU SystemCoreClock is %d Hz\r\n", SystemCoreClock);
-
- t.start();
-
- lcd.init();
+ pc.printf("CPU SystemCoreClock is %d Hz\r\n", SystemCoreClock);
+
+ t.start();
+
+ //lcd.init();
// lcd.setBrightness(0.05);
-
-
- // Read the WHO_AM_I register, this is a good test of communication
- uint8_t whoami = mpu9250.readByte(MPU9250_ADDRESS, WHO_AM_I_MPU9250); // Read WHO_AM_I register for MPU-9250
- pc.printf("I AM 0x%x\n\r", whoami); pc.printf("I SHOULD BE 0x71\n\r");
-
- if (whoami == 0x71) // WHO_AM_I should always be 0x68
- {
- pc.printf("MPU9250 WHO_AM_I is 0x%x\n\r", whoami);
- pc.printf("MPU9250 is online...\n\r");
- lcd.clear();
- lcd.printString("MPU9250 is", 0, 0);
- sprintf(buffer, "0x%x", whoami);
- lcd.printString(buffer, 0, 1);
- lcd.printString("shoud be 0x71", 0, 2);
- wait(1);
-
- mpu9250.resetMPU9250(); // Reset registers to default in preparation for device calibration
- mpu9250.MPU9250SelfTest(SelfTest); // Start by performing self test and reporting values
- pc.printf("x-axis self test: acceleration trim within : %f % of factory value\n\r", SelfTest[0]);
- pc.printf("y-axis self test: acceleration trim within : %f % of factory value\n\r", SelfTest[1]);
- pc.printf("z-axis self test: acceleration trim within : %f % of factory value\n\r", SelfTest[2]);
- pc.printf("x-axis self test: gyration trim within : %f % of factory value\n\r", SelfTest[3]);
- pc.printf("y-axis self test: gyration trim within : %f % of factory value\n\r", SelfTest[4]);
- pc.printf("z-axis self test: gyration trim within : %f % of factory value\n\r", SelfTest[5]);
- mpu9250.calibrateMPU9250(gyroBias, accelBias); // Calibrate gyro and accelerometers, load biases in bias registers
- pc.printf("x gyro bias = %f\n\r", gyroBias[0]);
- pc.printf("y gyro bias = %f\n\r", gyroBias[1]);
- pc.printf("z gyro bias = %f\n\r", gyroBias[2]);
- pc.printf("x accel bias = %f\n\r", accelBias[0]);
- pc.printf("y accel bias = %f\n\r", accelBias[1]);
- pc.printf("z accel bias = %f\n\r", accelBias[2]);
- wait(2);
- mpu9250.initMPU9250();
- pc.printf("MPU9250 initialized for active data mode....\n\r"); // Initialize device for active mode read of acclerometer, gyroscope, and temperature
- mpu9250.initAK8963(magCalibration);
- pc.printf("AK8963 initialized for active data mode....\n\r"); // Initialize device for active mode read of magnetometer
- pc.printf("Accelerometer full-scale range = %f g\n\r", 2.0f*(float)(1<<Ascale));
- pc.printf("Gyroscope full-scale range = %f deg/s\n\r", 250.0f*(float)(1<<Gscale));
- if(Mscale == 0) pc.printf("Magnetometer resolution = 14 bits\n\r");
- if(Mscale == 1) pc.printf("Magnetometer resolution = 16 bits\n\r");
- if(Mmode == 2) pc.printf("Magnetometer ODR = 8 Hz\n\r");
- if(Mmode == 6) pc.printf("Magnetometer ODR = 100 Hz\n\r");
- wait(1);
- }
- else
- {
- pc.printf("Could not connect to MPU9250: \n\r");
- pc.printf("%#x \n", whoami);
-
- lcd.clear();
- lcd.printString("MPU9250", 0, 0);
- lcd.printString("no connection", 0, 1);
- sprintf(buffer, "WHO_AM_I 0x%x", whoami);
- lcd.printString(buffer, 0, 2);
-
- while(1) ; // Loop forever if communication doesn't happen
+
+ //mpu9250.resetMPU9250();
+ // Read the WHO_AM_I register, this is a good test of communication
+ uint8_t whoami = mpu9250.readByte(MPU9250_ADDRESS, WHO_AM_I_MPU9250); // Read WHO_AM_I register for MPU-9250
+ pc.printf("I AM 0x%x\n\r", whoami);
+ pc.printf("I SHOULD BE 0x71\n\r");
+
+ if (whoami == 0x71) { // WHO_AM_I should always be 0x68
+ pc.printf("MPU9250 WHO_AM_I is 0x%x\n\r", whoami);
+ pc.printf("MPU9250 is online...\n\r");
+ // lcd.clear();
+ // lcd.printString("MPU9250 is", 0, 0);
+ sprintf(buffer, "0x%x", whoami);
+ // lcd.printString(buffer, 0, 1);
+ // lcd.printString("shoud be 0x71", 0, 2);
+ wait(1);
+
+ mpu9250.resetMPU9250(); // Reset registers to default in preparation for device calibration
+ mpu9250.MPU9250SelfTest(SelfTest); // Start by performing self test and reporting values
+ pc.printf("x-axis self test: acceleration trim within : %f % of factory value\n\r", SelfTest[0]);
+ pc.printf("y-axis self test: acceleration trim within : %f % of factory value\n\r", SelfTest[1]);
+ pc.printf("z-axis self test: acceleration trim within : %f % of factory value\n\r", SelfTest[2]);
+ pc.printf("x-axis self test: gyration trim within : %f % of factory value\n\r", SelfTest[3]);
+ pc.printf("y-axis self test: gyration trim within : %f % of factory value\n\r", SelfTest[4]);
+ pc.printf("z-axis self test: gyration trim within : %f % of factory value\n\r", SelfTest[5]);
+ mpu9250.calibrateMPU9250(gyroBias, accelBias); // Calibrate gyro and accelerometers, load biases in bias registers
+ pc.printf("x gyro bias = %f\n\r", gyroBias[0]);
+ pc.printf("y gyro bias = %f\n\r", gyroBias[1]);
+ pc.printf("z gyro bias = %f\n\r", gyroBias[2]);
+ pc.printf("x accel bias = %f\n\r", accelBias[0]);
+ pc.printf("y accel bias = %f\n\r", accelBias[1]);
+ pc.printf("z accel bias = %f\n\r", accelBias[2]);
+ wait(2);
+ mpu9250.initMPU9250();
+ pc.printf("MPU9250 initialized for active data mode....\n\r"); // Initialize device for active mode read of acclerometer, gyroscope, and temperature
+ mpu9250.initAK8963(magCalibration);
+ pc.printf("AK8963 initialized for active data mode....\n\r"); // Initialize device for active mode read of magnetometer
+
+ whoami = mpu9250.readByte(AK8963_ADDRESS, WHO_AM_I_AK8963); // Read WHO_AM_I register for MPU-9250
+ pc.printf("I AM 0x%x\n\r", whoami);
+ pc.printf("I SHOULD BE 0x48\n\r");
+ if(whoami != 0x48) {
+ while(1);
+ }
+ pc.printf("Accelerometer full-scale range = %f g\n\r", 2.0f*(float)(1<<Ascale));
+ pc.printf("Gyroscope full-scale range = %f deg/s\n\r", 250.0f*(float)(1<<Gscale));
+ if(Mscale == 0) pc.printf("Magnetometer resolution = 14 bits\n\r");
+ if(Mscale == 1) pc.printf("Magnetometer resolution = 16 bits\n\r");
+ if(Mmode == 2) pc.printf("Magnetometer ODR = 8 Hz\n\r");
+ if(Mmode == 6) pc.printf("Magnetometer ODR = 100 Hz\n\r");
+ wait(1);
+ } else {
+ pc.printf("Could not connect to MPU9250: \n\r");
+ pc.printf("%#x \n", whoami);
+
+ //lcd.clear();
+ //lcd.printString("MPU9250", 0, 0);
+ //lcd.printString("no connection", 0, 1);
+ sprintf(buffer, "WHO_AM_I 0x%x", whoami);
+ //lcd.printString(buffer, 0, 2);
+
+ while(1) ; // Loop forever if communication doesn't happen
}
mpu9250.getAres(); // Get accelerometer sensitivity
@@ -133,122 +152,215 @@
pc.printf("Accelerometer sensitivity is %f LSB/g \n\r", 1.0f/aRes);
pc.printf("Gyroscope sensitivity is %f LSB/deg/s \n\r", 1.0f/gRes);
pc.printf("Magnetometer sensitivity is %f LSB/G \n\r", 1.0f/mRes);
- magbias[0] = +470.; // User environmental x-axis correction in milliGauss, should be automatically calculated
- magbias[1] = +120.; // User environmental x-axis correction in milliGauss
- magbias[2] = +125.; // User environmental x-axis correction in milliGauss
+ // pc.printf("Magnetometer[0] adjust sensittivity is %f \n\r", magCalibration[0]);
+ // pc.printf("Magnetometer[1] adjust sensittivity is %f \n\r", magCalibration[1]);
+ // pc.printf("Magnetometer[2] adjust sensittivity is %f \n\r", magCalibration[2]);
+ // mRes = 10.*1229./4096.; // Conversion from 1229 microTesla full scale (4096) to 12.29 Gauss full scale
+ //mRes = 10.*1229./32760.;
+ // So far, magnetometer bias is calculated and subtracted here manually, should construct an algorithm to do it automatically
+ // like the gyro and accelerometer biases
+ //magbias[0] = -5.; // User environmental x-axis correction in milliGauss
+ //magbias[1] = -95.; // User environmental y-axis correction in milliGauss
+ //magbias[2] = -260.; // User environmental z-axis correction in milliGauss
+
+ // magbias[0] = +470.; // User environmental x-axis correction in milliGauss, should be automatically calculated
+ // magbias[1] = +120.; // User environmental x-axis correction in milliGauss
+ // magbias[2] = +125.; // User environmental x-axis correction in milliGauss
+
+
+
+ pc.printf("START scan mag\n\r\n\r\n\r");
+ //wait(1);
+ for(int i=0; i<800; i++) {
+ mpu9250.readMagData(magCount);
+
+ if(magCount[0]<xmin)
+ xmin = magCount[0];
+ if(magCount[0]>xmax)
+ xmax = magCount[0];
- while(1) {
-
- // If intPin goes high, all data registers have new data
- if(mpu9250.readByte(MPU9250_ADDRESS, INT_STATUS) & 0x01) { // On interrupt, check if data ready interrupt
+ if(magCount[1]<ymin)
+ ymin = magCount[1];
+ if(magCount[1]>ymax)
+ ymax = magCount[1];
+
+ if(magCount[2]<zmin)
+ zmin = magCount[2];
+ if(mz>zmax)
+ zmax = mz;
+
+
+
+ wait_ms(10);
+ }
+ pc.printf("FINISH scan\r\n\r\n");
+ pc.printf("Mx Max= %f Min= %f\n\r",xmax,xmin);
+ pc.printf("My Max= %f Min= %f\n\r",ymax,ymin);
+ pc.printf("Mz Max= %f Min= %f\n\r",zmax,zmin);
+
+
+
+ magbias[0] = ((xmax-xmin)/2.0f - xmax); // User environmental x-axis correction in milliGauss, should be automatically calculated
+ magbias[1] = ((ymax-ymin)/2.0f - ymax); // User environmental x-axis correction in milliGauss
+ magbias[2] = ((zmax-zmin)/2.0f - zmax); // User environmental x-axis correction in milliGauss
+
+ //magbias[0] = (xmin-xmax)/2.0f; // User environmental x-axis correction in milliGauss, should be automatically calculated
+ //magbias[1] = (ymin-ymax)/2.0f; // User environmental x-axis correction in milliGauss
+ //magbias[2] = (zmin-zmax)/2.0f; // User environmental x-axis correction in milliGauss
+ pc.printf("mag[0] %f",magbias[0]);
+ pc.printf("mag[1] %f",magbias[1]);
+ pc.printf("mag[2] %f\n\r",magbias[2]);
+ // resalt = atan(magY+((yMin-yMax)/2),magX+(xMin-xMax)/2))*180/PI;
- mpu9250.readAccelData(accelCount); // Read the x/y/z adc values
- // 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];
-
- mpu9250.readGyroData(gyroCount); // Read the x/y/z adc values
- // 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];
-
- mpu9250.readMagData(magCount); // Read the x/y/z adc values
- // Calculate the magnetometer values in milliGauss
- // Include factory calibration per data sheet and user environmental corrections
- mx = (float)magCount[0]*mRes*magCalibration[0] - magbias[0]; // get actual magnetometer value, this depends on scale being set
- my = (float)magCount[1]*mRes*magCalibration[1] - magbias[1];
- mz = (float)magCount[2]*mRes*magCalibration[2] - magbias[2];
- }
-
- 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++;
-
+
+ while(1) {
+
+ // If intPin goes high, all data registers have new data
+ if(mpu9250.readByte(MPU9250_ADDRESS, INT_STATUS) & 0x01) { // On interrupt, check if data ready interrupt
+
+ mpu9250.readAccelData(accelCount); // Read the x/y/z adc values
+ // 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];
+
+ mpu9250.readGyroData(gyroCount); // Read the x/y/z adc values
+ // 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];
+
+ mpu9250.readMagData(magCount); // Read the x/y/z adc values
+ // Calculate the magnetometer values in milliGauss
+ // Include factory calibration per data sheet and user environmental corrections
+ /* if(magCount[0]<xmin)
+ xmin = magCount[0];
+ if(magCount[0]>xmax)
+ xmax = magCount[0];
+
+ if(magCount[1]<ymin)
+ ymin = magCount[1];
+ if(magCount[1]>ymax)
+ ymax = magCount[1];
+
+ if(magCount[2]<zmin)
+ zmin = magCount[2];
+ if(mz>zmax)
+ zmax = mz;
+ wait_ms(1);
+ */
+ // pc.printf("FINISH scan\r\n\r\n");
+
+ mx = (float)magCount[0]*mRes*magCalibration[0] + magbias[0]; // get actual magnetometer value, this depends on scale being set
+ my = (float)magCount[1]*mRes*magCalibration[1] + magbias[1];
+ mz = (float)magCount[2]*mRes*magCalibration[2] + magbias[2];
+
+ // mx = (float)magCount[0]*1.499389499f - magbias[0]; // get actual magnetometer value, this depends on scale being set
+ // my = (float)magCount[1]*1.499389499f - magbias[1];
+ // mz = (float)magCount[2]*1.499389499f - magbias[2];
+
+
+
+
+ }
+
+ 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
-// mpu9250.MadgwickQuaternionUpdate(ax, ay, az, gx*PI/180.0f, gy*PI/180.0f, gz*PI/180.0f, my, mx, mz);
- mpu9250.MahonyQuaternionUpdate(ax, ay, az, gx*PI/180.0f, gy*PI/180.0f, gz*PI/180.0f, my, mx, mz);
+// }
+
+ // Pass gyro rate as rad/s
+ mpu9250.MadgwickQuaternionUpdate(ax, ay, az, gx*PI/180.0f, gy*PI/180.0f, gz*PI/180.0f, my, mx, mz);
+ // mpu9250.MahonyQuaternionUpdate(ax, ay, az, gx*PI/180.0f, gy*PI/180.0f, gz*PI/180.0f, my, mx, mz);
+
+ // 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);
- // 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("gx = %f", gx);
+ pc.printf(" gy = %f", gy);
+ pc.printf(" gz = %f deg/s\n\r", gz);
+
+ pc.printf("mx = %f", mx);
+ pc.printf(" my = %f", my);
+ pc.printf(" mz = %f mG\n\r", mz);
- pc.printf("ax = %f", 1000*ax);
- pc.printf(" ay = %f", 1000*ay);
- pc.printf(" az = %f mg\n\r", 1000*az);
+ whoami = mpu9250.readByte(AK8963_ADDRESS, AK8963_ST2); // Read WHO_AM_I register for MPU-9250
+ // pc.printf("I AM 0x%x\n\r", whoami); pc.printf("I SHOULD BE 0x10\n\r");
+ if(whoami == 0x14) {
+ pc.printf("I AM 0x%x\n\r", whoami);
+ while(1);
+ }
+
+
+ tempCount = mpu9250.readTempData(); // Read the adc values
+ temperature = ((float) tempCount) / 333.87f + 21.0f; // Temperature in degrees Centigrade
+ //pc.printf(" temperature = %f C\n\r", temperature);
- pc.printf("gx = %f", gx);
- pc.printf(" gy = %f", gy);
- pc.printf(" gz = %f deg/s\n\r", gz);
-
- pc.printf("gx = %f", mx);
- pc.printf(" gy = %f", my);
- pc.printf(" gz = %f mG\n\r", mz);
-
- tempCount = mpu9250.readTempData(); // Read the adc values
- temperature = ((float) tempCount) / 333.87f + 21.0f; // Temperature in degrees Centigrade
- 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("MPU9250", 0, 0);
- lcd.printString("x y z", 0, 1);
- sprintf(buffer, "%d %d %d mg", (int)(1000.0f*ax), (int)(1000.0f*ay), (int)(1000.0f*az));
- lcd.printString(buffer, 0, 2);
- sprintf(buffer, "%d %d %d deg/s", (int)gx, (int)gy, (int)gz);
- lcd.printString(buffer, 0, 3);
- sprintf(buffer, "%d %d %d mG", (int)mx, (int)my, (int)mz);
- lcd.printString(buffer, 0, 4);
- */
- // 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;
- yaw -= 13.8f; // Declination at Danville, California is 13 degrees 48 minutes and 47 seconds on 2014-04-04
- roll *= 180.0f / PI;
+ // 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]);
- pc.printf("Yaw, Pitch, Roll: %f %f %f\n\r", yaw, pitch, roll);
- pc.printf("average rate = %f\n\r", (float) sumCount/sum);
+ // 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]);
+
+ float Xh = mx*cos(pitch)+my*sin(roll)*sin(pitch)-mz*cos(roll)*sin(pitch);
+ float Yh = my*cos(roll)+mz*sin(roll);
+
+ float yawmag = atan2(Yh,Xh)+PI;
+ pc.printf("Xh= %f Yh= %f ",Xh,Yh);
+ pc.printf("Yaw[mag]= %f\n\r",yawmag*180.0f/PI);
+
+
+
+ pitch *= 180.0f / PI;
+ yaw *= 180.0f / PI;
+ yaw += 180.0f; // Declination at Danville, California is 13 degrees 48 minutes and 47 seconds on 2014-04-04
+ roll *= 180.0f / PI;
+
+ pc.printf("Yaw, Pitch, Roll: %f %f %f\n\r", yaw, pitch, roll);
+ pc.printf("average rate = %f\n\r", (float) sumCount/sum);
// sprintf(buffer, "YPR: %f %f %f", yaw, pitch, roll);
// lcd.printString(buffer, 0, 4);
// sprintf(buffer, "rate = %f", (float) sumCount/sum);
// lcd.printString(buffer, 0, 5);
-
- myled= !myled;
- count = t.read_ms();
+
+
+
+
+ myled= !myled;
+ count = t.read_ms();
- if(count > 1<<21) {
- t.start(); // start the timer over again if ~30 minutes has passed
- count = 0;
- deltat= 0;
- lastUpdate = t.read_us();
+ if(count > 1<<21) {
+ t.start(); // start the timer over again if ~30 minutes has passed
+ count = 0;
+ deltat= 0;
+ lastUpdate = t.read_us();
+ }
+ sum = 0;
+ sumCount = 0;
+ }
}
- sum = 0;
- sumCount = 0;
}
-}
-
- }
\ No newline at end of file