I have not tested the Active Life mat in Dolphin as I do not have a GC pad to USB adapter. If the Active Life mat can be detected by Windows, it can be mapped to Dolphin's emulated mat controller.
The information on the Active Life mat emulation is described here:
https://wiki.dolphin-emu.org/index.php?title=Active_Life:_Explorer
The information on the Active Life mat emulation is described here:
https://wiki.dolphin-emu.org/index.php?title=Active_Life:_Explorer
