Re: iPhone wind meter
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Layton</div><div class="ubbcode-body">I dunno about the whole microphone estimate thing. Too many ways to skew the numbers. </div></div>
I don't think it has anything do with microphones, it's just using the microphone port as a ways to communicate with the phone. He could've done the same thing using a USB port.
The wind speed measurement is based on the RPM of the turbine. I.e, they characterized the RPM response versus freestream velocity in lab, so that each RPM can be mapped to an estimate of the freestream velocity.
The microphone port is just for analog data transfer between the phone and the microcontroller on the windmeter.
The accuracy of these devices usually lies in correct calibration, as opposed to sophistication in the measurement device itself. I'd argue that the quality of this device depends much more on the programming of the iPhone app than the fairly simple (read: off the shelf) hardware.