Linkit Smart 7688 and Duo case

I remixed the http://www.thingiverse.com/thing:643264 to build a case for Linkit Smart 7688 Duo and Linkit Smart 7688.
One of the two allow also a gas sensor to be installed, but it can be easily customized with the OpenSCAD file.

It was originally created for the this project
http://www.seeedstudio.com/recipe/451-portable-fire-alarm-with-linkit-smart.html