The wiki page outlines several things that can be done with the accelerometers, and several that can't. For the etch-a-sketch or marble rolling application the more appropriate section of the page would be:
"When hand-held, and stationary, the phone has quite accurate (better than a degree) knowledge of where 'down' is. Tilt in two directions can easily be calculated Roll about the 'down' axis cannot." The paragraph quoted earlier in the thread then explains that by using the two accelerometers you can actually detect roll about the 'down' axis, but only if it is fast enough. In other words you can detect relatively gentle tilting for fine control of the marble, plus sharp rotation or translation if you want to rattle it about a bit. There is also realistic coverage of how the accels can be used to improve the accuracy of GPS readings, especially in a car, while making clear that full inertial navigation is a nonstarter. The source of the information looks like a combination of accelerometer datasheets and some basic physics. I've not checked the calculations, but they seem to be of the right order based on past experience with silicon accelerometers. Perhaps this is a case of the explanation making perfect sense to someone who already has experience in the subject, but not to those that don't. Any suggestions as to which bits need a better explanation? On Wednesday 14 May 2008, Mo Abrahams wrote: > That wiki page seems pretty pessimistic, making the accelerometers out > as being all but useless. What is the source of the information? > > On Tue, 2008-05-13 at 16:03 -0700, Steven Kurylo wrote: > > Are we going to be able to use the accelerometers for any of these games? > > > > The wiki says > > (http://wiki.openmoko.org/wiki/Technical:Accelerometer_Fundamentals#Resul > >ts) that "For gentle twisting and turning, the differential accelerations > > are impossible to tell from noise." To me that means rocking the neo > > around for these won't work. > > > > On Tue, May 13, 2008 at 3:41 PM, steve <[EMAIL PROTECTED]> wrote: > > > ya etch a sketch was one that we have talked about. > > > Too many ideas, > > > > > > > > > > > > > > > > > > -----Original Message----- > > > From: [EMAIL PROTECTED] > > > [mailto:[EMAIL PROTECTED] On Behalf Of Michael > > > Shiloh Sent: Monday, May 12, 2008 4:19 PM > > > To: List for Openmoko community discussion > > > Subject: Re: Freerunner games > > > > > > +1 for both of these. I can see Snake like this being quite exciting. > > > > > > I will award a t-shirt for a decent implementation of either of these. > > > Same for the Labyrinth game. > > > > > > Start coding. You'll be getting your Freerunners soon(ish)* > > > > > > Michael > > > > > > * for some definition of "soon" > > > > > > Ron K. Jeffries wrote: > > > > Etch-a-sketch using accelerometers would rock > > > > > > > > the classic Snake game would also be and cool > > > > with these controls > > > > > > > > > > > > -- > > > > Ron K. Jeffries > > > > http://blog.eronj.com > > > > _______________________________________________ Openmoko community mailing list [email protected] http://lists.openmoko.org/mailman/listinfo/community
