Prevent multiple simultaneous upload attempts

Signed-off-by: Maxim Osipov <maxim.osipov@gmail.com>
Add configurable sensors sampling rate (disabled for now)

Signed-off-by: Maxim Osipov <maxim.osipov@gmail.com>
Add light data collection

Signed-off-by: Maxim Osipov <maxim.osipov@gmail.com>
Add relative location tracking

Signed-off-by: Maxim Osipov <maxim.osipov@gmail.com>