[SOLVED] Accelerometer Question

[fsoender]

My accelerometer is showing 1.6v at 0 degree. The voltage goes up turning it one way, and goes downwards the other way. But on 180 degee it shows 1,6v again. Is this correct? How do I know if the accelerometer is 0 degree or 180 degree when they have same output value?

 

[FvM]

How do I know if the accelerometer is 0 degree or 180 degree when they have same output value?

You'll get more ambiguities by rotating the accelerometer around other axes. For an unequivocal detection of spatial orientation, you need not less than 3 orthogonal accelerometer channels.

 

[fsoender]

Thanks, but why do the Accelerometer give the same voltage twice over a 360 degree span?
Mine give:

0 - 1.5v
90 - 2.4
180-1.5v
270- 0.8v

 

[FvM]

1.5 V simply means zero g, gravitation force is orthogonal to the direction of sensitivity.

Think of accelerometer output = a*sin(phi) + b

 

[fsoender]

OK, I get that. But why is there 0g at 0 and 180 degree?

 

[dick_freebird]

Because at zero and 180 to horizontal, your Z acceleration
is orthogonal to the active axis of measurement and has (by
design) null output.