<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">I'm a little concerned about use of the word "orientation" for these kinds of events.<div><br></div><div>WebKit on iPhone already uses the term "orientation" to mean "which way up is the device", i.e. in portrait or landscape, right-way-up or upside-down:</div><div><<a href="http://developer.apple.com/iphone/library/documentation/AppleApplications/Reference/SafariWebContent/HandlingEvents/HandlingEvents.html#//apple_ref/doc/uid/TP40006511-SW16">http://developer.apple.com/iphone/library/documentation/AppleApplications/Reference/SafariWebContent/HandlingEvents/HandlingEvents.html#//apple_ref/doc/uid/TP40006511-SW16</a>></div><div><br></div><div>What you're talking about here is getting data from the accelerometer to describe arbitrary positions, so I think it would be clearer if these were called "accelerometer" events, or something else that distinguishes them from the usage that only applies to the cardinal angles.</div><div><br></div><div>Simon</div><div><br><div><div>On Sep 2, 2009, at 2:26 PM, Dave Burke wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div class="gmail_quote">On Mon, Aug 31, 2009 at 11:06 PM, Doug Turner <span dir="ltr"><<a href="mailto:doug.turner@gmail.com">doug.turner@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<div style="word-wrap: break-word;">Thanks Dave for your comments.<div><br></div><div>I was thinking about update frequency. right now, it is up to the UA (we are using 50ms).</div></div></blockquote><div><br>To give an explicit example, if you want to run a high pass (say to detect only sudden movements), you might code a simple k-order FIR filter of the form:<br>
<br> y[n] = b0.x[n] + b1.x[n-1] + ... + bk.x[n-k]<br><br>The coefficient values b0 ... bk are a function of the sampling rate ("update frequency") and hence needs to be settable or at least known to allow code portability.<br>
<br></div><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><div style="word-wrap: break-word;"><div><br></div><div>units -- yes. in g. This is best.</div>
<div><br></div><div>magnetometer -- but in a different API, right? I do not see directly how you would combined the two.</div></div></blockquote><div><br>It's a different API, but (can be) closely related. You can present magnetometer information either as x, y, z of the magnetic field vector or as the special case of compass orientation. For example, Android has the same <a href="http://developer.android.com/reference/android/hardware/SensorEvent.html">SensorEvent</a> for both Sensor.TYPE_ACCELEROMETER and Sensor.TYPE_MAGNETIC_FIELD. Lots of interesting use-cases for compass ranging from map tile orientation, navigation, augmented reality, etc.<br>
<br></div><blockquote class="gmail_quote" style="border-left-width: 1px; border-left-style: solid; border-left-color: rgb(204, 204, 204); margin-top: 0pt; margin-right: 0pt; margin-bottom: 0pt; margin-left: 0.8ex; padding-left: 1ex; position: static; z-index: auto; "><div style="word-wrap: break-word;"><div><div><br></div><div>Also see: <a href="http://dougt.org/wordpress/2009/08/orientation-update/" target="_blank">http://dougt.org/wordpress/2009/08/orientation-update/</a> for some demos.</div>
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