This is way beyond my skill, i'm describing the idea here in hopes people will build this and eventually make it it a cheaply avaiable kit or somthing.
The idea is to have the compass itself builtin the back cover, in order to get energy, either additional contacts to "steal" a bit of charge from the battery or somehow from the sd card slot. The data connection would be done via a ribbon cable with an SD card shaped tip, the tip would be inserted in the SD card slot, it would present itself as a SD card to the OS, commands to the compass and associated hardware would be done by writing to a file in the fake card, an reading back values and output of commands in general by reading from another file.
If possible, include a SD card slot in the backcover itself, to allow for real SD cards to be used as well, i'm not sure if the hardware and software would allow the system to make the N900 think it got two SD card slots or not, if possible the compass card would be the second and the real SD card would be the first to help with compatibility with progs that expect the N900 to only have one SD card slot, if not possible to fake two drives, have the input and output files of the compass be inside a series of subfolders (a bunch of them to reduce the risk of conflict with actual files on the real SD card), and incorporate those subfolders in the filetree of the SD card the N900 believes to be in the slot, together with the files of the real SD card, or just add it as a another partition separated from the partitions of the real SD card
Obviously effort should be taken to make sure the camera cover and the respective hole aren't impaired in their functionality,
Bonus points for having a modified foldin stand to allow for using the touchscreen with the stand deployed without needing to hold it to avoid it from tumbling like how it happens with the official stand, make it shaped like a trapezoid so it will also work for portrait mode
They used a gyro not a compass, and it communicated via bluetooth, not wires, also it was an experimental Nokia gyro, not somthing you can get easily.
Btw, i've searched the forums a bit and it seems there might exist techinology to allow a fully working digital compass to be fitted in an SD card form, i would consider that a secondary alternative because that would prevent you from using a regular SD card simultaneously, and a tiny thing close to the phone would probably be much more subject to interference than a bigger one mounted on the backcover.
this will b a really really great idea to have a digital compass, this will allow a better positioning system, not to mention will give better feeling to all games that uses motion., perhaps a visible ultra tiny compass at the back near the camera
What if it were that there were a replacement cover, with a doublewide, stronger kickstand, and the compass was in the other half, mirroring the camera bump, communicating via bluetooth, and running off a watch battery?
this will b a really really great idea to have a digital compass, this will allow a better positioning system, not to mention will give better feeling to all games that uses motion., perhaps a visible ultra tiny compass at the back near the camera
if its on the back. how will it help when playing games?
