Illuminated Door Lever lights up when locked
If you like your LED lights and don’t mind spending a lot of money on even the smallest of things, these door knobs are the way to go. Most of the time they will just look like a normal door handle, but once the lock is set these light up. They’re a great way to let everyone know that you really don’t want to be bothered. These come in a few different patterns, so you can find the one that suits you best.
You could attach one of these to a bathroom door or any type of in-home studio that you really would rather not be disturbed within. Now it’s not really absolutely necessary, after all someone could just try the handle to find out it’s locked. I’d prefer it if there was someway to push a button to illuminate the handle no matter if it’s locked or unlocked. If it did that, it’d make it nice for hotel room doors. That way you don’t have to slip outside to put a hanger on the door declaring you want to be left alone. To power the handle you’ll just have to pop in a single AA battery. You can purchase one of these for anywhere from $162 on up to $300 through Emtek.