Did anybody test if the accelerators could be used to program the n900 as microphone?

If the accelerators are sensible enough and fast enough the acceleration could be measured in a fixed sample rate.

This could be a very sensitive stereo microphone.

What?
I didn't get what you're trying to do...

The sound waves make vibrate the phone.

This acceleration can be measured.

If the acceleration sensors are fast enough we get a high sampling rate.

We get also the angle.

This locates the sound waves in stereo.

Why not use the real mic in n900?

Perhaps there are different characteristics.

(e.g.: Stereo)

I'd be very surprised if low-cost MEMS accelerometers have low enough noise to be used that way. But I'm willing to be proved wrong

The crucial point will probably be the sampling rate.

Does anybody have an information?

As an acoustician with a degree in acoustics I think I'm fairly qualified to answer this one.

There is no way that the accelerometers are a) sensitive enough to detect sound pressure waves over any meaningful frequency band and b) the accelerometers are in any way accurate enough to rely on correct measurements.

Also, there is no way that you can sample a stereo signal akin to the signal we pick up via our ears. You would need a setup like this to sample stereo airborne sound: http://www.bksv.com/products/telecom...type4128c.aspx

I do use accelerometers of a higher gade with signal processing equipment to measure ground-borne vibration. The in-built ones can be used for crude measurements but I think there's some software already out there much like the sound level meter software that uses the mic.

Sorry to put the idea down as I think these forums are what makes the os and the n900 so unique, but fact is fact.

Regards, James.

The accelerometer is a 3 axial one, it would be kinda like 6 unidirectional mics, with each pair pointing in opposite directions in axis ortogonal to the other axis. Not all sounds would be converted into motion of the accel so even if the sensitiivity and sampling rate were big enough things would sound kinda different somtimes (i imagine lower frequencies would be captured more loudly than higher frequencies), and there is also the question of the sampling rate, only sounds up to the frequency half the sampling rate can be picked.

Due to the geometry and materials used on the N900 certain frequencies would be absorbed or amplified differently depending on the direction to the source relative to the N900 (combining the oscilations from all axes, or perhaps even from just a single axis and analyzing the frequencies envelope might provide an increase in the direction detection capabilities, kinda like how holophonics trick the brain into hearing sounds from different directions using just two "microfones")