Hi, This is all about XBee Radios. Let's implement a Doorbell System. Based On Jeremy Blum Idea.
The system comprises two Arduino units, each equipped with an XBee shield and a radio module. One Arduino is positioned outside your home or apartment, while the other is located indoors. Upon pressing a button on the outdoor unit, the indoor board triggers the doorbell. Visit: / doorbell-xbee-radios