When I showed you my RaPiRo some post ago I explained why I would not use it as a case for my home automation server.
Let's summarize just something...
First of all the power. 12 motors are quite "hungry" and this means that using batteries is not an option if you need to keep it active all the day. You need to power with a plug, so it's mobility would be greatly limited.
It's noisy. All that motors can be quite annoying.
It can detect movement, but only when it's not moving itself, so it can check just a small area at a time.
There are other cons, but these are enough to let me think about a different solution for my home automation server.
