Add Bluetooth capability to your computer super fast with a USB BT 4.0 adapter. This adapter is backwards compatible with v2.1 and earlier, but also supports the latest v4.0/Bluetooth Low Energy. Inside lies a CSR8510 Bluetooth USB host.
We've used this with great success on a Windows 7 computer, installing as a 'generic' Bluetooth device, but we expect it to work just fine with any modern computer as this chipset is very common. So far we've tested it to communicate with Bluetooth data modules only.
Revision note: As of Friday, August 28th, 2015 these now have unique MAC addresses! That's great because now you don't have to worry about using two or more of them at once, handy for people turning these into beacons.
Drivers for CSR Bluetooth modules are built into Windows XP/7/8/10 so you do not need to install any software or download anything: other bluetooth drivers or 'stacks' such as BlueSoleil are not as good as the Windows stack and will cause problems. Just plug it in and let windows auto-install the BT driver, it may take a few minutes! For Linux, use Bluez which works great, our Pi tutorial will be similar to your favorite distro