Remotely turning on a LED - 200 feet away

(newbie alert)

My boyfriend works in a noisey environment in his garage. The garage is detached from the house. When a phone call comes for him, he can't hear a phone or feel a cell phone on vibrate.

I would like to buy (or build :-O ) a LED that he could strap to his arm like a wrist watch. When I'm in the house and hear the phone ringing, I can press a button and the LED on his wrist lights up.

Yes I COULD walk out to the garage and get him every time, that's what I've been doing. But by the 15th call of the day I'm thinking that I REALLY need to find a technical solution to this problem! So yeah this post is about me being lazy!

The LED / receiver would have to be battery powered in order to be mobile. The base unit with the button could be powered by AC or DC, it doesn't matter either way to me.

I thought about getting some electronics wiz to modify a remote control car but I don't think I would get the range necessary.

Any suggestions as to where to look for such a device or kit?

There are "wireless" remote-control switches to switch lamps,etc. by pushing a button on a keychain transmitter. Their range is ~ 30 meters but can be extended by adding a wire antenna. On websites like "allelectronics.com" such pairs are also available. Some experiments will be needed to optimize the operation.
Your friend can also use his cell phone kept in shirt pocket. Vibrator can be felt even in heavy noise environment.

You'll have to find a way to install led at the proper spot in the circuits.

1.

Lost keyring locator gadget. Press a button on the remote. Your keyring plays a beep.

2.

Wireless doorbell. Battery operated pushbutton sends signal to chime receiver. I've seen chime receivers that plug into house current. There may be a model that runs on battery.