On 4/1/08, Al Johnson <[EMAIL PROTECTED]> wrote: > On Tuesday 01 April 2008, Flemming Richter Mikkelsen wrote: > > On 4/1/08, Alexey Feldgendler <[EMAIL PROTECTED]> wrote: > > > In Norway, where I live, some tunnels are very long and even sometimes > > > contain internal enter and exit lanes, so there can be more than one way > > > to go. My Garmin navigator tries to estimate where I am basing on the > > > speed I had when entering the tunnel, so sometimes it notifies me of an > > > internal exit I have to take too late. > > > > Correct! We even have round abouts inside tunnels. If you take the wrong > > exit, > > you would have to drive for a long time to be able to turn and get back (on > > the > > highway). So the phone needs a system that is better than the one from > > Garmin. > > > > -=Flemming=- > > So you need a car cradle with a CAN interface - IIRC there have been USB-CAN > adaptors listed here before. This would give you access to the vehicle speed, > and perhaps other useful things - steering angle perhaps? Accelerometer input > for finding corners may be useful even if it's not accurate enough for > inertial navigation. The interesting part comes in combining the available > data to give the location estimate. >
What do we need the CAN interface for? We already know the speed before we enter the tunnel, and if the neo is in a car holder in a stable position, calibrated with some software, it knows from the accelerometers if we are driving strait ahead or making a turn and also if we are accelerating. With a little bit of mathematics, this can turn out to be very precise. -- Please don't send me Word or PowerPoint attachments. See http://www.gnu.org/philosophy/no-word-attachments.html Join the FSF as an Associate Member at: <URL:http://www.fsf.org/register_form?referrer=5774> _______________________________________________ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community