I wanted to be able to prevent my wife from getting welding flashes when she comes into the garage (My shop) without knocking. I couldn't train her to knock so I made this.

First I put a "Man's" bathroom sign.
Then i took some plexiglass rod that I had from something else.
(I imagine a clear stick for adjusting window blinds would work well too.)
I cut the rod .5" longer than the thickness of my door and rounded over one end.
I tried to heat it to make the ends clear but it did not work (still working on that solution).
The I drilled 2 holes where the eyes would be on the "Man" sign and jammed the rod in with the flush side going into the house and the .5" extra going into the shop.

If the lights are on in your shop the eyes will glow. if you are grinding near the door the eyes will glow orange (or whatever color the sparks are) and if you are welding and the light from the arc is getting on the door the eyes will glow very bright.

Man Sign before.jpg
Rounded Over Rod.jpg
View from house.jpg
View from Shop.jpg
Safety Guy after.jpg

Hopefully the pictures fill in the spaces in my description.
Any ideas or comments are welcome.