Triple-axis accelerometer with 3 analog outputs for X, Y and Z axis measurements on a 0.75″x0.75″ breakout board. The ADXL335 is the latest and greatest from Analog Devices. Runs from 1.8-3.6 volts (3.3 is suggested), with ratiometric output. That means that 0g measurement output is always at half of the supply voltage Vdd, -3g is at 0v and 3g is at Vdd with full scaling in between. Fully assembled and tested. Comes with 6 pin 0.1″ standard header in case you want to use it with a breadboard or perfboard. 4 x 0.125″ mounting holes for easy attachment. $20 in the Adafruit store.