kriswiner/BNO055

Some problems with software yaw angle

Closed this issue · 5 comments

brightproject commented

Hello mr. @kriswiner
I use BNO055 and this sketch

https://github.com/kriswiner/BNO055/blob/master/BNO_055_Nano_Basic_AHRS_t3.ino

The resulting roll and pitch angles from the BNO055 fusion and those calculated by the Madgwick or Mahony algorithm are similar.
But the yaw in Hardware is displayed according to turns, and in Software it is yaw.
Commenting a line:

// yaw *= 180.0f / PI;

Doesn't give results... because... there was a suspicion that yaw is somehow calculated in radians/sec.

void readMagData(int16_t * destination) {
 uint8_t rawData[6]; // x/y/z gyro register data stored here
 readBytes(BNO055_ADDRESS, BNO055_MAG_DATA_X_LSB, 6, &rawData[0]); // Read the six raw data registers sequentially into data array
 destination[0] = ((int16_t)rawData[1] << 8) | rawData[0] ; // Turn the MSB and LSB into a signed 16-bit value
 destination[1] = ((int16_t)rawData[3] << 8) | rawData[2] ;
 destination[2] = ((int16_t)rawData[5] << 8) | rawData[4] ;
} // readMagData

Output data

System Status = 0x5
Sensor fusion algorithm running
ax = 7 ay = -39 az = 1011 mg
gx = 0.00 gy = 0.06 gz = 1.37 deg/s
mx = 0 my = 66 mz = 8 mG
qx = 0.71 qy = 0.01 qz = 0.01 qw = -0.71
Gyro temperature is 41.0 degrees C
Software Roll, Pitch, Yaw: 0.14, -1.09, -1.57
Hardware Roll, Pitch, Yaw: 1.31, -2.06, 57.19
Hardware x, y, z linear acceleration: 15.00, -57.00, 9.00
Hardware x, y, z gravity vector: -35.00, 22.00, 979.00
rate = 307.44 Hz

The magnetic strength of the X axis is always 0, no matter how I rotate the board with the sensor.
The magnetometer sensor itself is fine, I ran the adafruit code and everything appears fine.
mag_telemetry_ok
I would appreciate your clarification if you find the time.

kriswiner commented
  • 👍1
brightproject commented

Wrong I2C address, improper calibration, some error in the sketch (although it has worked fine for me and others)....

Yes, I agree.
Any reason is possible, from modification of the sensor itself, to the specific device on which the code is running.
I use stm32f411.
And by the way, while I was writing this issue, I was doing the figure eight movement with a board with a sensor and... the mx axis suddenly showed the value 78 mG.
And in general I noticed that the period for updating the magnetometer values ​​is about 10-15 seconds.
Although all other values ​​are updated according to those set here

#define PERIOD_UPDATE (100)
if (delt_t > PERIOD_UPDATE) { // update LCD once per half-second independent of read rat
 // check BNO-055 error status at 10 Hz rate
}

Adafruit used this feature

https://github.com/rickkas7/Adafruit_BNO055_RK/blob/48e855b6da1e6aec86c83dce8b582a8a0b0d09f8/src/Adafruit_BNO055.cpp#L633

    /* Magnetometer offset range = +/- 6400 LSB where 1uT = 16 LSB */
    offsets_type.mag_offset_x =
        (read8(MAG_OFFSET_X_MSB_ADDR) << 8) | (read8(MAG_OFFSET_X_LSB_ADDR));
    offsets_type.mag_offset_y =
        (read8(MAG_OFFSET_Y_MSB_ADDR) << 8) | (read8(MAG_OFFSET_Y_LSB_ADDR));
    offsets_type.mag_offset_z =
        (read8(MAG_OFFSET_Z_MSB_ADDR) << 8) | (read8(MAG_OFFSET_Z_LSB_ADDR));
kriswiner commented
  • 👍1
brightproject commented

This I2C API: #include <i2c_t3.h> is written specifically for the Teensy 3.2 and will not work for the STM3

I'm used only Wire.h

// #include <i2c_t3.h>
// #include <SPI.h>
#include <Wire.h>
kriswiner commented
  • 😕1