Hi,
To make the gruvin9x board talk you need the addition of a second board.
One of these in fact:
http://www.4dsystems.com.au/prod.php?id=73
Pictures for the install can be found here:
http://www.th9x.com/g9x_v4_mods.zip
The pictures are slightly out of date in that they don't show the reset
wire that I added a few revisions ago. I will update them soonest and
let you know when I have.
As for the battery warning, I don't think their is a way to make it
haptic, bit of an omission really now you mention it. I'll have words.
Cam.
--
Cam