adxl345

Hello I am new to the forum, novice as they say, but I would like to challenge themselves in creating a position measuring system, is a project that I had thought some time ago '..... And for this I was thinking of using the sensor 3-axis ADXL345 which is very comprehensive, but also very complex, someone has already experienced this sensor? I found many codes, but none that made ??me understand how it can set the three axes to 0 on power up, and started to work from there ...
Let me explain I wanted to make a position control, 4-sensor ADXL345, which placed on 4 pillars of a bridge from the workshop, where I work, just lit it should be set to 0, then I should start measuring.
However, when moving the columns I went out to a certain value, they should play with a small buzer ... All 4 sensors I will feed them with batteries ..... 2 stylus ..?
Does anyone have a suggestion about ............... ??
Thank you.

Posting in English improves the chance for an answer in the international part of the forum,
Posting in the Italian section will help too.

google translate says:
Distacco in inglese migliora la possibilità di una risposta nella parte internazionale del forum,
Distacco nella sezione italiana aiuterà anche.