Newbee info - wireless transmission of a simple signal

Hi there.

I want to make a (small) simple device that can receive a signal from X numbers of transmitters. For example like the devices you get in some pizzaria’s - you get a small device witch will blink when your pizza is ready to be picked up.

I would like the range to be around 50-100 meters.

-this is a ‘new world’ to me - so if you can tell me where to get some generel info, please let me know.

br

Manice