Hi all, in application note AN5019, section 5.4(Inverse Soft-iron Matrix), formula(93), what if one of beta is negative? Then perform the sqrt is not allowable.

We make beta_0*beta_1*beta_2 to be positive in section 5.2, but we can not make sure beta_0,beta_1 and beta_2 all be positive, right?

What am I missing?

Thanks

Hello,

I'm trying to implement eCompass. It seems strange a negative Beta. Double check the matrix method.

Can you pass me the AN5019 document link because I can not find it?

I used the AN4246 document for the calculation of the beta and AN4248 for the algorithm.

Did you also considered you?

I downloaded a compass app on my tablet. Before starting the app tells you to move the tablet following a circuit like the infinity symbol with the screen facing up to eight times. This is to initialize the sensors.

We must also do it for the algorithm of freescale? I'll have found it written down somewhere.

How many samples you take to calculate the beta and what you send frequency magnetometer?

I think I have too low ...