The Ubertooth One is an opensource Bluetooth test tool from Michael Ossmann. It is the world's first affordable Bluetooth monitoring and development platform and is a fully open source product (both hardware and software).
Commercial Bluetooth monitoring equipment starts at about $10,000. Project Ubertooth seeks to produce an affordable platform that can be used for Bluetooth monitoring and for the development of new Bluetooth and wireless technologies.
Low-cost off-the-shelf Wi-Fi adapters have supported monitor mode for years, and the technique has found diverse uses in security research, troubleshooting, product development, intrusion detection, and more. Unfortunately, there has never been an equivalent tool for Bluetooth before Ubertooth One, a fully open source platform (both hardware and software).
Michael Ossmann presented Project Ubertooth: Building a Better Bluetooth Adapter at ShmooCon 2011.Download the Shmoocon presentation.