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    BNO055 accelerometer sensitivity


    Re: BNO055 accelerometer sensitivity

    Thanks for your response.

    So I'm a little bit confuse. In BNO055 datasheet (section 1.2 Eletrical and Physical Caracteristics, measurement performance) I can read the following information:
    Output Signal Accelerometer (Accelerometer Only Mode)
    Sensivity: 1LSB/mg

    So how the change of g-range from +-2g to +-4g or +-16g affects the sensivity of the Accelerometer in BNO055 sensor and why are you telling me to convert LSB to g following BMA280 datasheet? The two bytes of raw data in Accelerometer Only Mode are always in 1LSB/mg like datasheet say or not? Or this change if I change g-range? The two bytes of raw data in IMU Mode (fusion mode) use a fix g-range of +-4g and the sensitivity is fix to 1LSB/mg? 

    If raw data (accelerometer only mode aka NO fusion mode) change their own sensitivity based on g-range configuration the bno055_convert_float_accel_xyz_msq() functions in your API can't be used, since the divison of raw data by 100 always occurs, right? Can you explain all of this concepts step by step?

    Since the sensor is still on the market, Bosch should think about improving the sensor documentation (datasheet, application notes and so on...). All the information is very confusing and the questions on this forum about the BNO055 prove it.

    Best regards

    Community Moderator

    Re: BNO055 accelerometer sensitivity

    BNO055 register 0x3B bit 0 has defination of accel unit,  you can select the output unit as mg or m/s2.   

    This means the accel data was already convert inside BNO055 .  and directly output as mg or m/s2.  if you select output unit as mg,  then the sensitivity is 1mg/LSB.  

    When select the fusion mode,  the accel range is fixed to 4G range,  you can't change the range by yourself.  the output accel value in register on page 0 was converted according to its output unit.  

    WHen select non-fusion mode, you can change the acc range in register 0x08 on page 1 to other range like 8G,  the maximum range of accel will be changed,  the internal sensitivity from internal MEMS sensor output  was also updated.  but the accel value stored into BNO055 acc data read out register will be still 1mg/LSB.  those value are processed by BNO FW, converted to the desired unit,  not directly map the output register from internal MEMS sensor.