Some searching has turned up these public domain datasets

http://www.inf.ed.ac.uk/teaching/courses/dme/2014/datasets.html

http://www.ee.oulu.fi/~jaska/datasets.html

http://mldata.org/repository/data/viewslug/wearable-accelerometers-activity/

http://www-scf.usc.edu/~mizhang/datasets.html

In addition we’ve developed an Android app using AppInventor to capture accelerometer and magnetometer data as timeseries in .csv format and gmail it and backend google scripts that we will publish for our own data-capture and labelling