Why? It is actually a very simple thing, but yet I think would be very useful. Of course, what do you need a compass for when you have GPS? But still, why don't they put a sensor in the cell phone so it shows your direction?
-- xkuntay, Jan 18 2009

Riddle of the Compass http://findarticles..._21_161/ai_87353968
History, before cellphone compass [csea, Jan 18 2009]

Cell Phone Compass http://www.qcontinuum.org/compass/
One of Many [csea, Jan 18 2009]

//what do you need a compass for when you have GPS?//

In general, GPS won't tell you in what direction you are headed unless you are moving.

As it happens, I'm reading a history of the compass [link1] Fascinating!

For many years, I owned a watch band that featured a small compass, and I used it regularly. When the band wore out, I located a replacement in Korea, which lasted a few more years. Wish I had a high-quality version today.
-- csea, Jan 18 2009


Before the invention of the modern wristwatch, wrist-sundials were produced which contained built-in compasses.
-- supercat, Jan 18 2009


I do believe there are cellphones that allways tel the direction of Mekka. Or was that just a halfbaked idea?
-- zeno, Jan 18 2009


I have actually used the method suggested by "csea". I have a GPS smartphone. I start the GPSTEST program which shows your current lat/long, number of sats and heading. Run really fast in any direction so that the GPS program gets enough differential data to calculate a heading. Keep adjusting your course until you find the direction you're looking for. Watch out for trees and cars while doing it. Have fun looking like a complete dimwit running around in zig-zaggy lines while staring at your phone, in public.
-- diesixdie, Jan 18 2009


This is baked in the Google phone.
-- DenholmRicshaw, Jan 18 2009


I would have thought the interference of the Earth's magnetic field by nearby metal (ferrous) objects would render a compass in most urban environments pointless. Also, converting magnetic north to true north is a pain in the ass.

I've always liked the method of finding true north as follows: point the 12 hour notch of an analog watch towards the sun; halfway between the 12 hour notch and the hour hand is north (south for people in the northern hemisphere).
-- xaviergisz, Jan 18 2009


Very, very baked in several Nokia models, and has been for over three years [-]
-- AbsintheWithoutLeave, Jan 18 2009


What [Absinthe] said. Not sure whether the boutique brand "Nokia" is widely known thougH.
-- Texticle, Jan 18 2009


//boutique brand "Nokia"//
You're being ironic about the largest manufacturer of mobile phones in the world, right?
(For the record, of the top 25 best selling phones in November 2008, 17 were Nokias. iPhone came in around number 27)
-- AbsintheWithoutLeave, Jan 18 2009


Nokias are bloody awful. My latest has a three hour battery life.
-- DenholmRicshaw, Jan 18 2009


I've still got a Sanyo I bought in 2002. No compass though.

//Also, converting magnetic north to true north is a pain in the ass//

Maybe if you're travelling a whole lot... I've got a compass with a little screw in the bottom. You find out what the local difference between magnetic north and true north are, then set the screw, and you're done.

Fear not though, gyrocompasses don't rely on magnetic anomalies.
-- ye_river_xiv, Jan 18 2009



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