i don't know what happened but my lens camera doesn't work any more.
when i bought the n900 for the first place i needed to place a white sticker on the back of the lens cover to get it working but now it's stop to work.
when i open the camera application it's tell me to open the lens cover,but if i remove the back panel the camera application is working fine, i tried to run in the terminal the code "dmesg" and i get the flowing message:
"[ 615.015380] slide (GPIO 71) is now open
[ 630.296630] slide (GPIO 71) is now closed
[ 631.132537] kb_lock (GPIO 113) is now closed
[ 631.359008] kb_lock (GPIO 113) is now open
[ 758.353179] mmc0: cover is open, card is now inaccessible
[ 758.663024] mmc0: card aaaa removed
[ 761.968353] kb_lock (GPIO 113) is now closed
[ 762.148101] kb_lock (GPIO 113) is now open
[ 762.952758] cam_focus (GPIO 68) is now active
[ 763.049926] cam_launch (GPIO 69) is now active
[ 763.171630] cam_launch (GPIO 69) is now inactive
[ 763.218414] cam_focus (GPIO 68) is now inactive
[ 772.450775] mmc0: cover is closed, card is now accessible
[ 772.991943] mmc0: host does not support reading read-only switch. assuming write-enable.
[ 772.991973] mmc0: new high speed SDHC card at address aaaa
[ 772.998260] mmcblk0: mmc0:aaaa SU08G 7.40 GiB
[ 772.998596] mmcblk0: p1
[ 786.345214] mmc0: cover is open, card is now inaccessible
[ 786.656097] mmc0: card aaaa removed
[ 791.248657] mmc0: cover is closed, card is now accessible
[ 791.788757] mmc0: host does not support reading read-only switch. assuming write-enable.
[ 791.788818] mmc0: new high speed SDHC card at address aaaa
[ 791.794342] mmcblk0: mmc0:aaaa SU08G 7.40 GiB
[ 791.794647] mmcblk0: p1
[ 801.171478] slide (GPIO 71) is now open
[ 827.374664] slide (GPIO 71) is now closed
[ 828.109039] kb_lock (GPIO 113) is now closed
[ 828.282989] kb_lock (GPIO 113) is now open
[ 1263.960723] slide (GPIO 71) is now open"

please help me

Sorry to hear that but it seems the tiny magnet that was controlling lens on/off state fell off

Ok this is the start, i thought my sensor has stop working

where is that tiny magnet is located?

i do have a tiny magnet that fall off from the kickstand, i still have that magnet.