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### Topic: Force module, Newtonian physics, Galilean refencials. Classical physics? (Read 1 time)previous topic - next topic

#### Frederic_Plante

##### Sep 17, 2016, 06:28 pmLast Edit: Sep 17, 2016, 11:42 pm by Frédéric_Plante
Doing those gravity force calculation(g), it's all very nice, but the fact is we don't know the masses of the mobiles, so all these don't mean much and in the real world. The fact is we are calculating the acceleration.

Newtonian physic is richer then simply calculating a gForce. With very little math, we can also calculate speed and position with kinda great accuracy, by using a Galilean referential and differential/integral calculation.

We live in a classical world, on the daily basis, so I'm pretty sure that we could get more from these module then just knowing that, I'm turning and the gravity is pointing this way. I got the calculus under hand and I would be pleased to take the challenge of making a smarter library, but this is not the kind of thing that can be done alone.
As we fight our way northward into the great unknown, only that one thing remains certain...

#### jremington

Yep, agreed, classical physics all the way!

#### Frederic_Plante

#2
##### Sep 17, 2016, 10:20 pmLast Edit: Sep 17, 2016, 10:38 pm by Frédéric_Plante
Ok then, if there is interest, let's start by choosing a standard chip, I have a few kind digital and analog output, to collect raw force data, then we can put them in some equation, code, to start with.

2aΔs= vf2 - vi2

vi2= vf2 - 2aΔs

vf2 = vi2 + 2aΔs

Δs= (vf2 - vi2) ÷ 2a

a = (vf2 - vi2) ÷ 2Δs

Where a is the acceleration, Δs the space within where a happen, vf the final velocity and vi the initial velocity.

From those simple elements, we can deduce lots of stuff.
As we fight our way northward into the great unknown, only that one thing remains certain...

#### MarkT

MEMS accelerometers are hopeless for inertial guidance as they are too inaccurate and noisy.  Position
is the double integral of acceleration and that just drifts more and more with time.  There are ways to
compensate for drift if you have more information sources though.  For short term movement like
gesture recognition drift isn't an issue though.

And of course you need all 6DoF for any of this.
[ I DO NOT respond to personal messages, I WILL delete them unread, use the forum please ]

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