Danvel Wrote:
> tilt sensor will always think that the DF is horizontal because; whenever the gravity is tilted, it creates a sideways acceleration that counteracts the tilt exactly!. >

This is precisely what happens. I've tested the Analogue devices ADXL202 accelerometer chip.
They're great for absolute tilt angle sensing when they're stationary though.
For anyone who doesn't quite understand how these work: If you imagine a small weight anchored at each end with a metal spring and then picture what happens to the weight when you tilt it while stationary, or accelerate it forwards or backwards.

__\\\\\\\___|Weight|___\\\\\\\__

<<------Direction of Travel------->>

Hey Danvel ...... got some cool pushpull rail to rail output voltage comparator chips for driving FET gates. Check out National's LMC7211 SOT 23-5 package. They sink fully to ground and source to top +ve rail.

Cheers ADI