adxl accelerometer calibration

[praba_J]

i need some help to calculate acceleration,gravity,angle from accelerometer data.. i am using adxl330 and keil for programming.. i get the data from adc.. after that what i need to do for fall detection..how to proceed for fall detection algorithms..

 

[Jigar 4 Electronics]

you need to set a threshold acceleration value in Z direction.
I mean, make a formula to get the acceleration (See tutorial).
now trigger a software interrupt, when a higher acceleration in Z direction has detected.

 

[praba_J]

hi jigar.. thank you for your suggestion.. i already go through with that pdf..
vref=3.3v 12bit adc stm32f103 controller..
i got angle values on each axis by using these formula..
Axr = arccos(Rx/R)
Ayr = arccos(Ry/R)
Azr = arccos(Rz/R)
&
Axr = Axr*(180/3.14);
Ayr = Ayr*(180/3.14);
Azr = Azr*(180/3.14);

but the variation in each axis is very minimum..(left,right,backward,front)
for x-axis 112 to 118
y-axis 47 to 52
z-axis 47 to 51
this is correct or not?