[SMT] A Cubicle visitor alert system

Or, alternatively, help me make one. I have a EE degree but don'tknow how to begin thinking about this project.

Long story short, I usually can't hear when people come to visit my cube because I have headphones on. I'm looking to create a little wireless device that has a button that I can mount outside my cube, and a little LED light that I can mount near my screen. When someone presses the button, the light will flash informing me that I have a visitor.

TL;DR: want to create wireless doorbell but without the sound.