A. Yes you can attach this to a PC using an FTDI cable or an FTDI breakout board.
2. I wanted to know the actual circuit diagram or schematic
A. Diavolino schematics are here: http://www.flickr.com/photos/oskay/4727511688/
The full page is here: http://www.evilmadscientist.com/article.php/diavolino
If you were referring to the DrinkShield then the eagle files are in the SVN repo here: drinkshield.googlecode.com
3. I have a HC12 Dragon Board can that be used with the drink shield device?
A. The drinkshield was really just meant to be used with an Arduino (or Diavolino). You can use the code on an atmel chip and the shield itself only needs 4 pins (1 analog and 3 for the shift registers).
]]>1. Can I use this on a pc?
2. I wanted to know the actual circuit diagram or schematic
3. I have a HC12 Dragon Board can that be used with the drink shield device?