Does anyone know of plans or is anyone smart enough to design a load sensing switch like those in the fein and festool vacs that turn the vac on when it senses a load from your tool that is plugged into the outlet that is part of the vac?

I would guess a simple relay could do this, but I'm too ignorant to figure it out myself. Does someone make a power strip or extension cord with this feature built in?

Thanks!

Sam