We collected some data from a Megamini R4 board taped to the upper leg, to see how difficult it will be to detect sitting and standing.
Our test setup.
The Matlab output of our data. We collected the data using Teraterm from the serial output of the arduino, and formatted and graphed it using Matlab. We started with sitting, and transitioned to standing and back to sitting again. The transitions can be clearly seen, particularly in the first and third graphs (X and Z accel). The next step is to determine how difficult it will be to detect these transitions and not other activity.