Hi,

there is an integrated circuit from Analog Devices called the AD202XL,
which is a silicon implemented gravity sensor with great sensitivity. It
can be used as a precision tilt sensor. Will cost about 10 Dollars each.
An israeli-based compamy called ERM has a tilt sensor on offer called
T_Jack 2001, and inside is ...listen well... a PIC 12C508!!!
So this is a good application for a PIC. See the AD webpage for details on
this cutie.

Greetings

Jochen Feldhaar
DH6FAZ
jf@detektor.de