Accelerometer z axis problem

Questions & Answers
1

hi , I’m trying to build a project which uses accelerometer as its input . I created a guitext to debug and see how my Nexus S accelerometer works . I wrote this :

function Update()
{
 var phoneX = Input.acceleration.x ;
 var phoneY = Input.acceleration.y ;
 var phoneZ = Input.acceleration.z ;
 
 guiText.text = "phoneX : " + phoneX +
 "

phoneY : " + phoneY +
"
phoneZ : " + phoneZ;
}

I’m trying to use the z value of accelerometer . I think the axis are y is in direction of phone’s height , x in direction of phone’s width and z is the vector coming out of screen . but holding the phone parallel to the floor and rotating it around it’s z doesn’t affect any of the accelerometer’s values.

I’ll be appreciated if someone can help me with this

thanks

2

That’s right. The only acceleration constantly acting over the accelerometer is the gravity. With the phone parallel to the floor, the whole gravity is applied opposite to the Z axis direction, thus it should show a value -1 (-1 G) while the other axes should be 0. Slowly rotating it to the upright position will move gravity from Z to the Y axis, and you should get Y = -1 and Z,X = 0 when completely vertical.

Maybe you’re confusing accelerometer with gyroscope - a gyroscope can track rotations, while the accelerometer only reports the result of forces acting on the phone - usually fast movements (shaking, hitting, etc.)