NOT FINISHED YET!!! My first try to get a self built fully working Quadrocopter based on an mbed, a self built frame and some other more or less cheap parts.
Sensors/Comp/HMC5883.cpp
- Committer:
- maetugr
- Date:
- 2012-10-18
- Revision:
- 11:9bf69bc6df45
- Child:
- 12:67a06c9b69d5
File content as of revision 11:9bf69bc6df45:
#include "mbed.h" #include "HMC5883.h" HMC5883::HMC5883(PinName sda, PinName scl) : i2c(sda, scl) { // initialize HMC5883 for scaling writeReg(HMC5883_CONF_REG_A, 0x19); // 8 samples, 75Hz output, test mode for scaling! writeReg(HMC5883_CONF_REG_B, 0x20); // Gain for +- 1.3 gauss (earth compass ~0.6 gauss) writeReg(HMC5883_MODE_REG, 0x00); // continuous measurement-mode // Scaling for(int j = 0; j < 3; j++) // set all scales to 1 first so the measurement for scaling is not already scaled scale[j] = 1; int data50[3] = {0,0,0}; // to save the 50 measurements for(int i = 0; i < 50; i++) // measure 50 times the testmode value to get an average { read(); for(int j = 0; j < 3; j++) data50[j] += data[j]; } scale[0] = (1.16 * 1090)/(data50[0]/50.0); // value that it should be with selftest of 1.1 Gauss * 1090 LSB/Gauss / the value it is scale[1] = (1.16 * 1090)/(data50[1]/50.0); scale[2] = (1.08 * 1090)/(data50[2]/50.0); // set normal mode writeReg(HMC5883_CONF_REG_A, 0x78); // 8 samples, 75Hz output, normal mode } void HMC5883::read() { char buffer[6]; int dataint[3]; readMultiReg(HMC5883_DATA_OUT_X_MSB, buffer, 6); // join MSB and LSB of X, Z and Y (yes, order is so stupid, see datasheet) dataint[0] = (short) (buffer[0] << 8 | buffer[1]); dataint[1] = (short) (buffer[4] << 8 | buffer[5]); dataint[2] = (short) (buffer[2] << 8 | buffer[3]); for(int j = 0; j < 3; j++) { Min[j]= Min[j] < dataint[j] ? Min[j] : dataint[j]; Max[j]= Max[j] > dataint[j] ? Max[j] : dataint[j]; data[j] = dataint[j]/1.090; //* scale[j]; } heading = 57.295779513082320876798154814105*atan2(data[1], data[0]); } void HMC5883::writeReg(char address, char data){ char tx[2]; tx[0] = address; tx[1] = data; i2c.write(I2CADR_W(HMC5883_ADDRESS), tx, 2); } void HMC5883::readMultiReg(char address, char* output, int size) { i2c.write(I2CADR_W(HMC5883_ADDRESS), &address, 1); //tell it where to read from i2c.read(I2CADR_R(HMC5883_ADDRESS) , output, size); //tell it where to store the data read } /* void HMC5883::Calibrate(int s) { //Ende der Kalibrierung in ms Millisekunden berechnen int CalibEnd= GlobalTime.read_ms() + s*1000; while(GlobalTime.read_ms() < CalibEnd) { //Update erledigt alles Update(); } AutoCalibration= AutoCalibrationBak; }*/ // Winkel berechnen //--------------------------------------------------------------------------------------------------------------------------------------- float HMC5883::getAngle(float x, float y) { #define Rad2Deg 57.295779513082320876798154814105 #define PI 3.1415926535897932384626433832795 float Heading; float DecAngle; DecAngle = 1.367 / Rad2Deg; //Missweisung = Winkel zwischen geographischer und magnetischer Nordrichtung //Bern ca. 1.367 Grad Ost //http://www.swisstopo.admin.ch/internet/swisstopo/de/home/apps/calc/declination.html Heading = atan2((float)y,(float)x); Heading += DecAngle; //bei Ost-Deklination += DecAngle, bei West-Deklination -= DecAngle if(Heading < 0) Heading += 2*PI; //korrigieren bei negativem Vorzeichen if(Heading > 2*PI) Heading -= 2*PI; //auf 2Pi begrenzen return (Heading * 180/PI); //Radianten in Grad konvertieren }