BMI160 Questions

Other Hardware Sensors
1

Hello all!

I am using a BMI160 to detect the heeling angle of a sailboat. I need to know the current angle of the sensor at all times to do this.

I have wired and coded a setup that works just fine, but... I cant figure out how to know my current angle in degrees! How would I do this? And I don't understand what the BMI160 is outputting for information; like unit of measurement or something.

Thanks in advance!

Code:

/*!
 * @file accelGyro.ino
 * @brief I2C addr:
 * @n  0x68: connect SDIO pin of the BMI160 to GND which means the default I2C address
 * @n  0x69: set I2C address by parameter
 * @n Through the example, you can get the sensor data by using getSensorData:
 * @n get acell by paremeter onlyAccel;
 * @n get gyro by paremeter onlyGyro;
 * @n get both acell and gyro by paremeter bothAccelGyro.
 * @n With the rotation of the sensor, data changes are visible.
 * @copyright	Copyright (c) 2010 DFRobot Co.Ltd (http://www.dfrobot.com)
 * @license The MIT License (MIT)
 * @author  DFRobot_haoJ(hao.jiang@dfrobot.com)
 * @version V1.0
 * @date 2017-12-01
 * @url https://github.com/DFRobot/DFRobot_BMI160
 */

#include <DFRobot_BMI160.h>

float xcurrentpos;
float ycurrentpos;
float zcurrentpos;

DFRobot_BMI160 bmi160;
const int8_t i2c_addr = 0x69;

void setup(){
  Serial.begin(115200);
  delay(100);
  
  //init the hardware bmin160  
  if (bmi160.softReset() != BMI160_OK){
    Serial.println("reset false");
    while(1);
  }
  
  //set and init the bmi160 i2c address
  if (bmi160.I2cInit(i2c_addr) != BMI160_OK){
    Serial.println("init false");
    while(1);
  }
}

void loop(){  
  int i = 0;
  int rslt;
  //int16_t accelGyro[6]={0}; 

    ////only read gyro data from bmi160
  int16_t onlyGyro[3]={0};
  rslt = bmi160.getGyroData(onlyGyro);

  //get both accel and gyro data from bmi160
  //parameter accelGyro is the pointer to store the data
  //rslt = bmi160.getAccelGyroData(accelGyro);
  if(rslt == 0){
    xcurrentpos = xcurrentpos += (onlyGyro[0]*3.14/180.0);
    ycurrentpos = ycurrentpos += (onlyGyro[1]*3.14/180.0);
    zcurrentpos = zcurrentpos += (onlyGyro[2]*3.14/180.0);

    Serial.print("X: " + String(onlyGyro[0]*3.14/180.0));
    Serial.print(" Y: " + String(onlyGyro[1]*3.14/180.0));
    Serial.print(" Z: " + String(onlyGyro[2]*3.14/180.0));
    Serial.print(" XC: " + String(xcurrentpos));
    Serial.print(" YC: " + String(ycurrentpos));
    Serial.println(" ZC: " + String(zcurrentpos));

/*
    for(i=0;i<3;i++){
      //if (i<3){
        //the first three are gyro data
      Serial.print(onlyGyro[i]*3.14/180.0);Serial.print("\t");
      //}
      //else{
        //the following three data are accel data
      //  Serial.print(onlyGyro[i]/16384.0);Serial.print("\t");
      //}
    }
    Serial.println();
  }else{
    Serial.println("err");*/
  }
  delay(100);
  /*
   * //only read accel data from bmi160
   * int16_t onlyAccel[3]={0};
   * bmi160.getAccelData(onlyAccel);
   */
   
}
2

Did you read the datasheet?

The interesting bits seem to start on page 30.

3

Hello @jfjlaros , thanks for the response!

Yes, I read through some of it, but I was pretty lost. I did see that it outputs gyro data at 125˚/s, which is adjustable. I'm not sure what that means though.

4

For the angle of heel, you need the accelerometer data, not the gyro data, I think.

5

Hello @PaulRB :wink:

The gyro detects heeling angle in degrees, like on a drone. The BMI160 also outputs accelerometer data, but I will not be needing that.

Edit:
I did just find this link though, which uses accelerometer data to find the angle in degrees :thinking:.

6

You are correct @PaulRB, my apologies.

1 Like
7

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