xn1ch1:
I've ordered a 3 axis accelerometer, I assumed that's what a gyroscope was.
That's the right answer. An accelerometer detects acceleration in a given direction. If you have three of them covering all three axes, and they're attached to something which is essentially stationary, you can use this to work out the direction of gravity which tells you which way is 'up'.
A gyro is used to detect rotation around an axis, which is no help to you here.