Please help me save my marriage...

[Max Coller]

Ok, so we've covered visual indicators (strobes, Christmas lights.)

We've got suggestions for auditory (bell, chime, phone, high-pitched and decidedly disappointed whine of a Mother In Law.)

We've got tactile (cell phone on vibrate.)

What about olfactory? I'm pretty sure if I smelled smoke signals while I was in the middle of cutting tenons on the table saw I'd cease operations pretty quickly, but still in a safe and orderly manner. The logistics of a remote-control smoke signal aren't terribly challenging - for example a remote starter for model rockets.

[phil harold]

if the phone works you can get one of these
http://www.smithgear.com/krn-k-ra-005.html

[Tony Perrone]

Olfactory indicators would not work for me. I am sent out to the shop to fart all the time so all other smells would be masked

[Stan Krupowies]

Olfactory indicators would not work for me. I am sent out to the shop to fart all the time so all other smells would be masked

Don't even think about giving that little tip to my wife! I'd be spending all night in my shop.

[Forrest Bonner]

NO, NO, NO! The only good advice above is to get her to NOT EVEN OPEN THE DOOR if a machine is running. Any distraction that diverts your attention from that very sharp, rapidly moving blade near at hand can lead to a trip to the emergency room. Happened to me, happens to others every day. If she doesn't love you enough to do that, well, maybe you should re-think the living arrangement.
Forrest

[ray hampton]

buy a motion sensing camera and wired the camera to flashing lights