Gumstix Computer
Figure 14: Gumstick computer (upper left) and Bluetooth module (center)
(Click image to enlarge)
The Gumstix computer is a wonderful piece of technology, worthy of its own article or review. As you can see from Figure 14, the computer is the same size as a stick of gum. The Bluetooth module is a separate piece, with both pieces fitting inside a white plastic chassis. The computer runs an embedded version of Linux (based on on the 2.6 kernel) and has an MMC flash memory slot for saving the results of your Bluetooth scanning.
Since the computer is so small and consumes little power (three AAA batteries provide 6-8 hours of runtime), other interesting Bluetooth scanning devices can be made. You could make a very small handheld Bluetooth sniffer that could be carried in your pocket or perhaps thrown in the bushes outside of a building. This could passively scan for devices until you retrieved it to look at the results.