The advantage of using HG (or any other similar HA software) is that it supports a number of protocols given the right hardware. Since you have X10, you could use any of the X10 motion sensors but, IMO, they are all junk at consistency. I have a few installed but I absolutely hate them. They fail if they get wet (even when silicon prevention is taken) and their range is garbage (even with the passive antenna mod). I have not found a wireless motion sensor yet, but any protocol that HG supports will work. I do have a wired sensors I installed long ago. I initially interfaced using a PowerFlash module but after burning it up during a wind storm, I switched to using the RPi GPIO. This is faster, WAY more reliable, and easily accomplished with HG.