How to measure tilt angle with very small component?

How to measure tilt angle with very small component?
In goolge, the results is a little big in size.
And I don't want to use A-sensor, G-sensor, because the reference plane may be not perticular.
many thanks.

I've seen to a young friend how he implemented a small IC angle sensor with analog output in one of his robots, using Arduino.

I don't know exactly which one was:
http://www.st.com/web/en/catalog/sen...er/FM89/SC1288
http://www.dowaytech.com/en/d/file/p...3F-EN-V1.1.pdf

You can build a small PCB with an angle sensor IC with analog output an place them on your DUT, after calibrating using a reference angle meter. Place also on board some buffer op amps, and you can read the angle from a distance.

perpendicular?

A 3-D g-sensor can do it well.