digital compass on n900
 

Does the n900 has digital compass? ive read somebody say yes, and somebody say no, can anybody please confirm, if the answer is yes, how can i use it? is it possible to have access to it from python?

thanks in advance

seb.

Re: digital compass on n900
 

No.......................

Re: digital compass on n900
 

Inside Ovi maps, one of the buttons on the lower left bottom.
You can click on the North button to rotate the map orientation...

Re: digital compass on n900
 

true but that doesnt mean theres a builtin compass. ur simply manually rotating the map. the map also rotates when ur driving according to the change in position i believe... in other words no builtin compass

Re: digital compass on n900
 

The gps recognizes N, S, E, W based on the sat lock and the direction the phone is moving in and orients the map accordingly, hence the map's ability to rotate.

Re: digital compass on n900
 

it's quite sad really that N97 got the compass but the N900 which using the same GPS chip but losing the compass. I don't know why would they do that to a good device. Should have left the compass in for developer to make use of it.

Re: digital compass on n900
 

Why give overcomplicated answers to confuse the issue further?

Digital compass = no.

PS: No, a GPS cannot replicate the functionality of a digital compass.

Re: digital compass on n900
 

acctually the n00 has a better GPS unit. i think its one of the best

Re: digital compass on n900
 

I've not been that bothered about a compass before -- sure, helpful for navigation, but once you start moving the problem goes away.

Then a friend showed me a great "star gazing" app on his iphone which displays star constellations etc aligned with where the phone is pointing. Actually very nice & useful (for some people!)

So, compass=good, but don't have it. Netx phone perhaps..

Re: digital compass on n900
 

Try stellarium

Re: digital compass on n900
 

dunno about that my g1 can get a lock inside my house instantly the n900 just blinks none stop

Re: digital compass on n900
 

Is it a GPS lock or is it just cell phone tower triangulation? I used to have a G1 and was not very fond of the GPS.

Re: digital compass on n900
 

To speed up GPS: settings--positioning--posserver change the supl.nokia.com to supl.google.com

That will make the gps lock-on like 10 times faster then standard setting.

Enjoy.

Re: digital compass on n900
 

How much are we loosing by not having a compass?

Re: digital compass on n900
 

Not a huge amount - it'd help with aligning maps properly, and is critical for most augmented reality applications. I'd rather have one than not, but I'm not overly fussed about missing one.

Re: digital compass on n900
 

thats a troll question :P

we a loosing a lot of things because the n900 its not like lot of phones (talking about unsolvable hardware differences)

also, n900 its quite different to any gadget out there (for good)

Re: digital compass on n900
 

Hi!

I am also trying to get some sort of digital compass for my N900, and as far as I checked the price and shipping costs for all the parts necessary for simple IC2 -> Bluetooth digital compass, for me it is cheaper, faster and easier to just buy used Android phone (G1/Dream or Tattoo), attach it to the back of N900 with two elastic bands, and create a simple App that transmits compass coordinates from Android phone via Bluetooth/WiFi. I know it sounds completely stupid, but it solves all the battery/circuitry/soldering/etc problems for the same price or cheaper, AND I get an additional phone. :D ;) Mind if I include this as one of the options in the Digital Compass wiki section? :)

Edgars

Re: digital compass on n900
 

Other solutions:

My questions about digital compass:

1) Is it possible to use a second gps by bluetooth? The n900 could calculate the direction by difference. (I know that gps is not very exact. But perhaps both bluetooth receivers do the same mistake. So the direction could be correct.)

2) Perhaps the same thing is possible with the gps of the n900 only: you fix a location with gps first (by pressing some button) then you move the the n900 to another place and the n900 calculates the direction by difference.

3) Wintec wsg 1000 http://www.wintec-gps.de/wintec_wsg-1000.php
This external bluetooth gps-receiver has also a compass and other features.
There are even linux development tools for cp2101
http://forum.pocketnavigation.de/for...000-usb-linux/

http://forum.pocketnavigation.de/for...x/#post2209994

Re: digital compass on n900
 

A bluetooth compass isn't that useful unless physically mounted on the n900 somehow, since you have to make sure it's constantly pointing in the same direction as the n900. The great thing about an internal compass is that as you rotate the phone around, the map or VR view changes.

Re: digital compass on n900
 

It's true that a compass on the device is very nice.

But I don't think that a bluetooth compass would be useless.

First of all:
You don't need a compass to follow a map. My old pocketloox t830 has no compass and follows the map by GPS. That is no problem as far as you are moving. Only if you are standig immobile the device loses its orientation. You don't need a compass to follow a map. For this application a compass is more or less useless.

A compass is usefull, if you are standing at a place and want information of what you see in a direction.
In this case there is no difference if you point in that direction by the n900 or by a bluetooth compass.
(I think even that a separated pointer would be more confortable. You can fixe your eyes on an immobile spot.)


The third case are games with a digital compass. You have to play them the bluetooth device fixed to the n900. That is no problem during a little game.




I think that in all those cases a bluetooth compass would be an acceptable solution. And this compass has even additional features:
temperature sensor, altimeter, independent gps logger, movement sensor ....
Perhaps those informations could also be interesting for some applications.

Unconventional compass
 

I've got a proposition for a compass that isn't mentionned in the wiki.

I've looked at the light sensor of the n900.
It is very complex!!!
It is even able to distinquish different colors. (The lux are integrated over a spectrum).

If there was an expert for hardware he could even write an application for color recognition with this sensor.

It would be possible to construct a compass with that.

You take a little ball compass (1cm diameter). You color the different parts of the compass: for example: North is red, less north is less red. West is blue, less west is less blue. Yellow is up, no yellow is down.
This colored ball compass you put on the light sensor. It makes a color analysis and gives the direction!

Wouldn't that be wunderful?

Re: Unconventional compass
 

that sounds very creative!
try it! im curious if it will work
maybe if someone takes care of the hardware part the sftware will come up also!
burt... very creative!!

Re: Unconventional compass
 

Unfortunately in a real world objects don't have color. If you light it with white lite object would have one color, at sunset light would be much more red and object's color would become warmer. At lite of night outdoor sodium lamps everything is yellow, all other colors turn to black.
But can you please describe how to read channels from light sensor?

Re: digital compass on n900
 

Yeah - the lack of a compass does make the GPS very unpredictable. A strange miss, and one that makes the N900 even more of a half-baked handset than it is.

Quite apart from star gazing apps, digital compasses also make augmented reality apps possible - Although GoSkyWatch is awesome, especially on the iPad.

Re: digital compass on n900
 

@KiberGUS

Did you also think about fluorescent/ luminescent paint ?

Re: digital compass on n900
 

http://www.stellarium.org/

I'm looking for star gazing apps for the N900 - i see the one you mentioned supports linux - does that mean it can run on the n900

if so... what do i have to do?

thanks! :)

Re: digital compass on n900
 

i'm not sure but a hardware is required (which the n900 is lacking)

Re: digital compass on n900
 

It's a real shame, would make it possible to write some cool augmented reality apps if it were present (i.e. something like camera view with overlaid locations of landmarks, wikipedia entries, etc.)

Re: digital compass on n900
 

I have an idea which I think will work for "emulating" compass functionality on the N900. Here is how it would work:

Using the date, time, and GPS coordinates, the app should be able to know where the sun or moon is located in the sky and their direction on a compass.

With GPS turned on and the date and time set correctly, the user can point to the sun during the day, or the north pole star (or moon) during the night.

The app should now be able to know which direction on the compass the user is holding the phone to. Consider this the user calibrating or setting/resetting the "compass" app.

From that point on, the app uses information from the phone's hardware (GPS and accelerometer) to update the "compass" information as the user moves the phone around.

If the accelerometer works the way I understand it works from this page (http://wiki.forum.nokia.com/index.ph..._N900_using_Qt), then this should work pretty well, shouldn't it?

EDIT: After playing with the AccDisplay app, I don't think the accelerometer will help keep track of the orientation. The accelerometer can detect all movements and orientation except for rotations around the z-axis because that's the same access gravity pulls at! Unfortunately, that's exactly the kind of rotation you'd need in a compass application :( I guess the only remaining solution is the information from the GPS hardware, which relies on phone movement, but that only tells you the direction the phone is moving in, not necessarily where it's oriented. Big bummer :(

Hamzeh

Re: digital compass on n900
 

And how would it work if you can't see the sun (cloudy day, or even night time)?
I have a better idea for you, and it doesn't require any device what-so-ever - if you're outside, you may sometimes notice that the sun rises from the east and sets in the west, so if its not exactly the middle of the day (12:00), you should be able to know roughly which direction is the east or west respectively, thus finding the north :)
There is another way of finding out, which is a bit more accurate which I was taught during my military service, but I'm afraid its not that easy to explain in words ;)

Re: digital compass on n900
 

It is ported to N900's architecture (armel): http://packages.debian.org/lenny/stellarium which means it runs on Linux/ARM (little endian).

AFAIK not ported to Maemo 5. You could ask for a port, pay someone to port it to Maemo 5, or try it in Easy Debian. You'll probably have to use stylus though. GPS should work since that uses standard protocols. IIRC it also utilizes OpenGL; might be a problem performance-wise, but hopefully you can 'downgrade' the quality. Your question might be worth a different topic.

Re: digital compass on n900
 

If all you need is the Sun or Moon's position (or a planet), try orrery. It's a lot faster than stellarium (though not nearly as beautiful!).

Re: digital compass on n900
 

Stellarium is fully ported to Maemo 5, and runs well on the N900. It's in extras devel. It's a bit of a CPU/battery hog, but it is an extremely impressive app, and one of the best things to show off the phone's power to your friends. It makes Google Sky look like a Palm Pliot app from 1995.

Re: digital compass on n900
 

Yeah, it wouldn't work well when there are clouds blocking sky objects. I was thinking the user can point to a known object in the area and from that the app would look up the direction information.

I know how to roughly find out where E and W are :) but the idea was to somehow have the phone know that too so that apps could have access to that information.

Re: digital compass on n900
 

I remember hearing/reading many years ago, that if you hold a watch horizontally and point the hour hand (non-digital-display, obviously) at the sun, then the direction of Noon on the clock is where North is. As the sun gets later and moves further round, so does the hour hand, hence noon always points at the same place. Although I'm not sure if its very reliable at extreme setting/rising angles of the sun during certain parts of the year.

Could you use one of the cameras to detect the sun direction (if visible and if the phone is flat) and do the same thing, as it knows the time and the season (as it knows which country you're in)? Doesn't work at night, obviously (I don't think using the stars is a feasible idea)... Or when inside, or its very cloudy.

Re: digital compass on n900
 

Just get a watch with a compass. Casio makes some relatively cheap ones, as well as more expensive ones with other features, such as a barometer/altimeter and thermometer. I have the Casio with those features, and it is very useful.

However, I think most digital compasses need to be kept at a certain angle (flat to the ground) to be accurate. if not flat, the error can be really big, like 40 degrees or so.

Re: digital compass on n900
 

Can you attach a real compass to front camera some how in a better way than this and use the camera to generate compass data?

http://www.shapeways.com/materials/frosted_detail

May be with help of super glue to make a water based one (floating in watertight cylinder)

Re: digital compass on n900
 

The rear camera can focus down to 6 cm. You could move that tiny compass to the other side, mount it 6 cm away, capture an image, and write some image processing software to derive the needle's orientation.

Re: digital compass on n900
 

does the image need to be focused? I'm thinking of something like solid black coin with axis hole that let light shine through it.

Re: digital compass on n900
 

So basically using the front camera as a light-intensity sensor & have the light intensity depend on the rotation of the compass disk ? :)