Excellent project – “This is the first in a series of articles that will provide step-by-step instructions for implementing Bluetooth Proximity Detection. We’re going to focus on using it with Asterisk@Home. But your imagination is really the only limitation. At the very least, when we’re finished, you’ll be able to walk out of your home or office carrying your bluetooth phone or headset and have your Asterisk server automatically transfer your incoming calls to your cellphone.” Link.
HOW TO – Bluetooth proximity detection with Asterisk