This is a three axis accelerometer for the LilyPad system. Based on the ADXL335 accelerometer from Analog Devices, the LilyPad Accelerometer can detect joint movement as well as inclination and vibration.
So you want to measure the shifts in gravity on a wearable piece of electronics, eh? Flip your hand up/sideways/over, you'll be able to tell using the ADXL335 on this breakout board.
The ADXL335 outputs a 0V to 3V analog signal on each of the X, Y, and Z axis. You will need to convert this analog voltage to a gravity amount and use trigonometry to calculate a true 'angle'. If you are not looking for tilt, it is very easy to use this sensor for basic motion sensing.
LilyPad is a wearable e-textile technology developed by Leah Buechley and cooperatively designed by Leah and SparkFun. Each LilyPad was creatively designed to have large connecting pads to allow them to be sewn into clothing. Various input, output, power, and sensor boards are available. They're even washable!