Participants were supplied with either an HTC Wildfire S or
an HTC Desire S smartphone, both running identical
versions of the Android OS. Each phone was supplied with
a 3G data card to connect to the HTTP server. A
commercial wrist actigraphy device, a CamNtech
Actiwatch 4 actigraphy device [9], was also given to the
participants. The device was programmed to record activity
between 0.35 - 7.5 Hz at an epoch of 0.25 minutes.