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    BMM150 coordinate origin

    BMM150 coordinate origin

    New Poster

    Where in the 1.56 x 1.56 x 0.6 mm body of the BMM150 magnetometer is considered the Origin ?    

    I couldn't find any information in the datasheet about where the sensor is taking its measurements.

    The geometric centre seems like a good bet, to minimize errors. but I would like to be as precise as possible here.

    I'm using an array of BMM150s for my application, and I need to know their measurement point-coordinates for a model.


    12 REPLIES 12

    Has anybody figured this one out?  Does Bosch have any documentation about the locations of their sensors' axis datums?  The chip is small, and for many applications it could be considered a point source. but with my array here I need to know where each measurement is taken 

    Community Moderator
    Community Moderator

    This may not be the complete answer, but hopefully this previous reply could be a step in the right direction.

    Community Moderator
    Community Moderator

    Hello misterMark,

    After our internal discussion, we couldn't understand your previous clearly, could you provide give detailed description for your previous description. For example, your specific application details, the details of what you expect sensor to do in your application. Thanks.
    Previous description: "Correct I am trying to use an array of BMM150s , and my model would benefit to know precisely where every measurement is being measured within the BMM150. In my application I am sampling small, passive magnetic fields, and analyzing the gradient dropoff from the source. When nearby to a magnet, even a fraction of a millimeter can have a huge impact on the strength of the field measurements. So I'd like to be as precise as possble."

    Community Moderator
    Community Moderator

    Hello misterMark,

    Do you have further feedback?

    Hi there, sorry for the delay in my reply.

    We have three sensors, and we are trying to measure the magnetic field gradient between the sensors (ie. the DIFFERENCE in magnetic field). 

    For example: to calculate the gradient between Sensor 1 and Sensor 3 in the picture below, we subtract Sensor1's measurement from Sensor3's measurement. But we need to know the DISTANCE over which the gradient is measured, so we can get the gradient in MicroTesla / Metre.

    magnet sensors.png

    We assumed that the three axes measure with respect to the same location in the center of the sensor, see A below. But this appears not to be the case. Maybe the origin is offset and all three are measured on one side? or maybe the axes all measure from different points in the sensor IC? 


     I hope this clarifies my question.  Where do each of the axis measure from?