<p> Monitoring Bluetooth is hard. Hackers accustomed to 802.11 have been spoiled by ubiquitous, inexpensive hardware capable of monitor mode, but similar tools are not available for Bluetooth. Off-the-shelf Bluetooth adapters are capable of monitoring only by actively joining a network, and they are unable to passively collect the information required in order to join. Efforts to build custom monitoring systems to date have been limited by Bluetooth's frequency hopping through 79 channels.</p><p> We will review the options available today for passive Bluetooth monitoring with an emphasis on software radio techniques. Although single channel monitoring with software radio has been demonstrated before, we will show how to extend the technique to all 79 channels and how to predict the target network's pseudo-random hopping sequence using passively collected information. The presentation will feature a live demonstration and the release of open source tools.</p>