Hi All !
Wanted to suggest on tilt sensor. I mean make one. I don't know if it's correct....

Take a Circular (light weight) disk, pass an axle through the center of the disk. connect the axle to some small box so that the disk is vertical. Now add some weight (like small Nut-bolt ) at the edge (circumference)of the disk. Now due to gravity, this place where you have added weight will point down wards.
1) You can connect a potentiometer to the axle, so when the box is tilted the disk moves due to the weight and thus axle moves the potentiometer causing change in resistance.
Or 2) you can keep some sensor at the circumference of the circle ..like let's say contact brush on the weight (Nut-bolt) which will slide against some metal strips ....which are mounted at the circumference of the disk and are fixed to the Box. as the disk moves due to tilting of box the brush will make contact with some metal strips. Connect 5v to the axle (metal) and electrically short the weight (Nut-Bolt) to axle . Now when the brush slides on the metal stripes , it'll connect 5v to it. And if you have 8 such strips can connect it to the 8bit data bus through some buffer.

I hope this'll work . :-)
Regards
Vignesh baliga