Hi! This is my first post here.
I am working on a project which involves working on ADXL345 and Arduino UNO. ADXL345 is supposed to detect impacts in all directions.

I am using ADXL345 in 10-bit resolution with +/-16g range.

I have been facing a number of problems here :
1. Despite putting ADXL345 on a flat surface there is an offset in Axis - Z values.

2. MAJOR PROBLEM!!! : While I was doing some controlled testing to set a threshold, I put the value of TapThreshold as 170 (~5g). I tried to hit it softly and observed that it is detecting a tap. The value of force was nowhere close to the threshold.

I re-checked all the connections but this thing is getting out of control now.
You can get the code and library files here: http://bildr.org/?s=accelerometer (Tap! Tap!....)
Any help would be appreciated.
Thanks!

 

Be sure your not creating a mechanical fulcrum with the accelerometer and the point where acceleration is to be detected.
That would seriously lower the force needed to activate your sensor

 

How does it react to the tap when on a soft surace like foam rubber?

 

Be sure your not creating a mechanical fulcrum with the accelerometer and the point where acceleration is to be detected.
That would seriously lower the force needed to activate your sensor

I fixed the accelerometer on a car-bot and made it run with a constant velocity and BANG!!!
Still nothing to cheer about.
Thank for replying.