It should be added that in addition to the OTG cable, you'll need a USB Power Adapter Y Cable.
Originally Posted by bdbr
The power can be provided by the touchpad charger or any PC USB Port, or if you need portability, one of those cellphone portable charger with a USB port will do.
The general wiring is:
To manually mount the file system, you run in XTerm:
Touchpad---OTG Cable------USB Y Cable------USB Device
/ <--(short split of the Y Cable)
I tried connecting it directly to my Nikon DLSR, but the camera got stuck at the "Connecting to PC" step and never properly mounted on the touchpad, but it works beautifully with keyboards and thumbdrives.
mount /dev/sda1 /media/internal/usb