Bedroom. I use a little thing I made to make the screen go black when ever someone comes in the room (a usb connection + button near my foot. boom)
That sounds like the stupidest thing ever.
Let's imagine you're on your computer in your bedroom, viewing something that your parents wouldn't want you to see.
Your door opens, your parent walks in, you press your foot down, your screen goes black, your parent sees you sat at your computer with a black screen doing nothing at all. (and let's imagine it was something naughty you were watching, and you happen to be sat in an unusual stance...)
Definitely not suspicious at all.