The ADXL335 is a small, thin, low power, 3-axis accelerometer with signal conditioned voltage outputs. The module measures acceleration with a range of ±3 g. It can measure the static acceleration of gravity in tilt-sensing applications, as well as dynamic acceleration resulting from motion, shock, or vibration. The user reads the analog signals at the XOUT, YOUT, and ZOUT pins.

NOTE:  This module requires between 1.8 and 3.6VDC.  It should be powered using the 3.3V pin on the Arduino not 5V!

Here is a good tutorial to connect this device to an Arduino.

Datasheet of ADXL335 chip

Calibration