I had posted a link awhile back on the Facebook group for the DIY Auto-Switch. When you turn on your Router it turns on your vacuum automatically, then when you shut off your router the vacuum runs for 5 seconds longer (can be changed) before turning off.
A quick vid of it up and running. Hard to hear when I turn on the router but the vac instantly turns on. Once the router is off you can hear just the vac running for 5 secs.
The upside of the power outlets is I have a one-to-many relationship where any of my on switches (router, jigsaw, chopsaw, bench) trigger the vac and can de-activate it. The problem I have is remembering to move the vaccum hose now! I need to get it over head and probably do a little project to shunt between various hoses automatically, but that’s outside my reach for now…
Another caution is to make sure the load carrying components are rated for an inductive load. If they are not I would de-rate them at least 50% and use a mettalic box to be safe.