Do 'plug-in' spider repellents work?

I'm looking for something to deter spiders. I live in a converted barn with lots of beams & it seems to be a spider haven! They are mive too! The other night I woke up because I thought a mouse was in my room, but it turned out to be a huge hairy spider rustling & scuttling around the floor - eeeooowww!! Has anyone tried those 'plug-in' repellents??