Compute the difference from accelerometers to determine the thingy speed and movement on the hands and one on the body.

[titof49]

Hi,

I m using now two thingy and I m looking for the possibility to compute the difference between the two accelerometer to determinate the the moment of one compared to the second.

After having yihs information, I 'll use it to determinate speed and moment.

Your advice about the accelerometer used in the thingy and the possibility to do It ?

Bye,

Christophe.

[ovrebekk]

Hi

You only have access to the raw accelerometer data, so everything else you have to calculate yourself. 

If you integrate the accelerometer data over time you should be able to get an estimate of the speed and angle, but the measurements are quite noisy so you will aggregate more and more error over time. If you can detect when the Thingy is still you can use that to reset the integrated speed, so that you can reduce the impact of the error, but this assumes that the Thingy is not being moved around for prolonged periods of time. 

I don't know what your application is, but I wouldn't rely on the Thingys to provide very accurate positional information ;)

Best regards
Torbjørn

[ManuGira]

Hello,

I also intend to integrate the raw acceleration twice to get an estimate of the position over a short perdiod of time (1 or 2 seconds)

However I can't understand the values I get from the raw acceleration. What is the unit used for raw acceleration? Is it in m/s/s ?
From what I have measured, it doesn't seems to be m/s/s, because the norm of my acceleration vector is about 0.0316 when the Thingy is still (instead of the expected 9.81 due to gravity).

In other words, it looks like my measured acceleration is about 310 times smaller than reality. Is that a normal result or I my doing something wrong?

Sunny regards,

Emmanuel

[ovrebekk]

Hi Emmanuel

Sorry for the slow response. Since you verified my answer the case dropped out of my active case list. 

Did you figure this out?

Best regards
Torbjørn