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Dependencies:   mbed

Dependents:   fluy343

IMU/Sensors/Gyro_Acc/MPU6050.cpp@4:b0a60b0b24a9, 2014-02-15 (annotated)

Committer:
maetugr
Date:
Sat Feb 15 14:28:11 2014 +0000
Revision:
4:b0a60b0b24a9
Child:
5:06e978fd147a
After setting MPU6050 up

Who changed what in which revision?

UserRevisionLine numberNew contents of line
maetugr 4:b0a60b0b24a9 1 #include "MPU6050.h"
maetugr 4:b0a60b0b24a9 2
maetugr 4:b0a60b0b24a9 3 MPU6050::MPU6050(PinName sda, PinName scl) : I2C_Sensor(sda, scl, MPU6050_I2C_ADDRESS)
maetugr 4:b0a60b0b24a9 4 {
maetugr 4:b0a60b0b24a9 5 // Turns on the MPU6050's gyro and initializes it
maetugr 4:b0a60b0b24a9 6 // register datasheet: http://www.invensense.com/mems/gyro/documents/RM-MPU-6000A.pdf
maetugr 4:b0a60b0b24a9 7 writeRegister(MPU6050_RA_PWR_MGMT_1, 0x01); // wake up from sleep and chooses Gyro X-Axis as Clock source (stadard sleeping and with inacurate clock is 0x40)
maetugr 4:b0a60b0b24a9 8 writeRegister(MPU6050_RA_GYRO_CONFIG, 0x18); // scales gyros range to +-2000dps
maetugr 4:b0a60b0b24a9 9 writeRegister(MPU6050_RA_ACCEL_CONFIG, 0x00); // scales accelerometers range to +-2g
maetugr 4:b0a60b0b24a9 10 }
maetugr 4:b0a60b0b24a9 11
maetugr 4:b0a60b0b24a9 12 void MPU6050::read()
maetugr 4:b0a60b0b24a9 13 {
maetugr 4:b0a60b0b24a9 14 readraw_gyro(); // read raw measurement data
maetugr 4:b0a60b0b24a9 15 readraw_acc();
maetugr 4:b0a60b0b24a9 16
maetugr 4:b0a60b0b24a9 17 for (int i = 0; i < 3; i++)
maetugr 4:b0a60b0b24a9 18 data_gyro[i] = (raw_gyro[i] - offset_gyro[i])*0.07; // subtract offset from calibration and multiply unit factor (datasheet s.10)
maetugr 4:b0a60b0b24a9 19
maetugr 4:b0a60b0b24a9 20 for (int i = 0; i < 3; i++)
maetugr 4:b0a60b0b24a9 21 data_acc[i] = raw_acc[i] - offset_acc[i]; // TODO: didn't care about units because IMU-algorithm just uses vector direction
maetugr 4:b0a60b0b24a9 22 }
maetugr 4:b0a60b0b24a9 23
maetugr 4:b0a60b0b24a9 24 int MPU6050::readTemp()
maetugr 4:b0a60b0b24a9 25 {
maetugr 4:b0a60b0b24a9 26 char buffer[2]; // 8-Bit pieces of temperature data
maetugr 4:b0a60b0b24a9 27
maetugr 4:b0a60b0b24a9 28 readMultiRegister(MPU6050_RA_TEMP_OUT_H, buffer, 2); // read the sensors register for the temperature
maetugr 4:b0a60b0b24a9 29 return (short) (buffer[0] << 8 | buffer[1]);
maetugr 4:b0a60b0b24a9 30 }
maetugr 4:b0a60b0b24a9 31
maetugr 4:b0a60b0b24a9 32 void MPU6050::readraw_gyro()
maetugr 4:b0a60b0b24a9 33 {
maetugr 4:b0a60b0b24a9 34 char buffer[6]; // 8-Bit pieces of axis data
maetugr 4:b0a60b0b24a9 35
maetugr 4:b0a60b0b24a9 36 readMultiRegister(MPU6050_RA_GYRO_XOUT_H | (1 << 7), buffer, 6); // read axis registers using I2C // TODO: why?! | (1 << 7)
maetugr 4:b0a60b0b24a9 37
maetugr 4:b0a60b0b24a9 38 raw_gyro[0] = (short) (buffer[0] << 8 | buffer[1]); // join 8-Bit pieces to 16-bit short integers
maetugr 4:b0a60b0b24a9 39 raw_gyro[1] = (short) (buffer[2] << 8 | buffer[3]);
maetugr 4:b0a60b0b24a9 40 raw_gyro[2] = (short) (buffer[4] << 8 | buffer[5]);
maetugr 4:b0a60b0b24a9 41 }
maetugr 4:b0a60b0b24a9 42
maetugr 4:b0a60b0b24a9 43 void MPU6050::readraw_acc()
maetugr 4:b0a60b0b24a9 44 {
maetugr 4:b0a60b0b24a9 45 char buffer[6]; // 8-Bit pieces of axis data
maetugr 4:b0a60b0b24a9 46
maetugr 4:b0a60b0b24a9 47 readMultiRegister(MPU6050_RA_ACCEL_XOUT_H | (1 << 7), buffer, 6); // read axis registers using I2C // TODO: why?! | (1 << 7)
maetugr 4:b0a60b0b24a9 48
maetugr 4:b0a60b0b24a9 49 raw_acc[0] = (short) (buffer[0] << 8 | buffer[1]); // join 8-Bit pieces to 16-bit short integers
maetugr 4:b0a60b0b24a9 50 raw_acc[1] = (short) (buffer[2] << 8 | buffer[3]);
maetugr 4:b0a60b0b24a9 51 raw_acc[2] = (short) (buffer[4] << 8 | buffer[5]);
maetugr 4:b0a60b0b24a9 52 }
maetugr 4:b0a60b0b24a9 53
maetugr 4:b0a60b0b24a9 54 void MPU6050::calibrate(int times, float separation_time)
maetugr 4:b0a60b0b24a9 55 {
maetugr 4:b0a60b0b24a9 56 // calibrate sensor with an average of count samples (result of calibration stored in offset[])
maetugr 4:b0a60b0b24a9 57 // Calibrate Gyroscope ----------------------------------
maetugr 4:b0a60b0b24a9 58 float calib_gyro[3] = {0,0,0}; // temporary array for the sum of calibration measurement
maetugr 4:b0a60b0b24a9 59
maetugr 4:b0a60b0b24a9 60 for (int i = 0; i < times; i++) { // read 'times' times the data in a very short time
maetugr 4:b0a60b0b24a9 61 readraw_gyro();
maetugr 4:b0a60b0b24a9 62 for (int j = 0; j < 3; j++)
maetugr 4:b0a60b0b24a9 63 calib_gyro[j] += raw_gyro[j];
maetugr 4:b0a60b0b24a9 64 wait(separation_time);
maetugr 4:b0a60b0b24a9 65 }
maetugr 4:b0a60b0b24a9 66
maetugr 4:b0a60b0b24a9 67 for (int i = 0; i < 3; i++)
maetugr 4:b0a60b0b24a9 68 offset_gyro[i] = calib_gyro[i]/times; // take the average of the calibration measurements
maetugr 4:b0a60b0b24a9 69
maetugr 4:b0a60b0b24a9 70 // Calibrate Accelerometer -------------------------------
maetugr 4:b0a60b0b24a9 71 float calib_acc[3] = {0,0,0}; // temporary array for the sum of calibration measurement
maetugr 4:b0a60b0b24a9 72
maetugr 4:b0a60b0b24a9 73 for (int i = 0; i < times; i++) { // read 'times' times the data in a very short time
maetugr 4:b0a60b0b24a9 74 readraw_acc();
maetugr 4:b0a60b0b24a9 75 for (int j = 0; j < 3; j++)
maetugr 4:b0a60b0b24a9 76 calib_acc[j] += raw_acc[j];
maetugr 4:b0a60b0b24a9 77 wait(separation_time);
maetugr 4:b0a60b0b24a9 78 }
maetugr 4:b0a60b0b24a9 79
maetugr 4:b0a60b0b24a9 80 for (int i = 0; i < 2; i++)
maetugr 4:b0a60b0b24a9 81 offset_acc[i] = calib_acc[i]/times; // take the average of the calibration measurements
maetugr 4:b0a60b0b24a9 82 }