As far as I remember, OpenIntent's Sensor Simulator managed to emulate compass somehow, however, didn't look details.
Regards, Alex On May 19, 3:33 pm, "[EMAIL PROTECTED]" <[EMAIL PROTECTED]> wrote: > Hi James, > > This is helpful. Thank you. It is good to know someone is thinking > about this. After reading the IEEE abstract, a little clarification on > use is always helpful. > > Our applications are eyes free, because the phone should not be > competing for those revenue generating resources. So use will happen > with the phone stored on the person’s body, say, in a shirt pocket, > held to the person's ear, or on their belt. The compass needs to work > no matter how the phone is oriented. The IEEE abstract seemed unclear > on how it would work in a handheld device. It would be great for cars, > though. With the two accelerometers, there is a calibration routine > where a person wears the phone normally and walks in one direction. 10 > ft should be enough to get enough calibration to be useful. It can > recalibrate in the background and alarm or adjust ... > > Sensor Fusion is a new word for me. Differential sensors of finite > resolution have been around for a long time. Consider the roach, or > any bug with antennae. They sample air at distant points allowing the > organism to select a direction. The longer the antennae, the smaller > the gradient the organism can detect with sensors of a fixed > resolution. Long antennae help folks figure out what is going on. > Sampling acceleration at distant points is going to give you better > information on angular velocity and acceleration (how fast you are > spinning) than using a single sensor in the same way. > > Thank you for pointing out that radio field interaction can provide > information... since a human body can influence that, it is probably > good to not rely on that method. Two sensors a fixed distance apart > should require little attention and provide good results across many > devices once it is engineered. > > My job is to show why it is worthwhile to spend that dollar for > pedestrians who don’t read maps. Android has the tools to do that, > even in today’s SDK. > > On May 18, 7:48 am, James <[EMAIL PROTECTED]> wrote: > > > > > A MEMS chip can be a collection of sensors (temperature, accelerometer > > (x,y,z), atmospheric pressure, Hall effect sensor (compass), ...) all > > built into the same chip. In mass production the chip could be > > relatively inexpensive. > > >http://ieeexplore.ieee.org/Xplore/login.jsp?url=/iel5/20/35967/017046.... > > > However, an Android shortcut would be to use the GPS sensor and your > > relative direction of travel to produce a compass bearing over 100 > > feet of uniform travel. For each model of cell phone the antenna > > sensitivity changes as you rotate the cell phone about a point. This > > could potentially be tied in with relative position movement to > > estimate a compass bearing about a point. > > > But as I said, the lookup table would be different for each model of > > cell phone. > > > This type of engineering where you take two sensors with low > > resolution to combine their results to provide greater resolution is > > called "Sensor Fusion". > > > Basically a cell phone antenna signal does NOT have the same signal > > profile when you rotate left versus rotate right. This can be > > capitalized upon to determine the relative bearing of which the > > compass is facing. Coupled with the cell phone GPS the relative > > bearing can be referenced to the true bearing. A lookup table can > > provide a correction factor and thereby produce Magnetic Bearing; vis > > vi Compass. > > > James Dunn > > Table of Contents - Similar Insights related to technology > > applicationshttp://blog.360.yahoo.com/jamesbdunn?p=207 > > > On May 15, 9:23 pm, "[EMAIL PROTECTED]" <[EMAIL PROTECTED]> wrote: > > > > I have no idea how much a cell phone with a compass costs. I don't see > > > why it would be expensive if there were enough of a market to micro > > > machine it like all those tiny mirrors. > Who knows these answers? > > > > Thanks, > > > Ed- Hide quoted text - > > > - Show quoted text -- Hide quoted text - > > - Show quoted text - --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Android Discuss" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/android-discuss?hl=en -~----------~----~----~----~------~----~------~--~---
