Loving Yosemite, Apple’s latest version of OS X but you cannot get Continuity / Hand-off working with your iOS8 device and computer? Chances are you don’t have a computer that has the required Bluetooth Low Energy 4.0 chipset — needs to be a model year 2012 or later. No worries, you can swap out the Bluetooth module pretty easy as Apple uses the same modules on different computers. Check out my latest video on YouTube that shows how to get your Late 2011 Model MacBook Pro 15″ (13″ should be similar) working with Continuity.
You’ll need to order the correct Bluetooth module for your MacBook Pro — be certain that is has the “CAX” marking, not just AX. I used the following one from eBay — New MacBook Pro A1278 A1286 A1297 Unibody AirPort Extreme Card for 2011-2012.
For further assembly instructions check out the great guides on ifixit.
You can download the patch script from here: http://www.mavromatic.com/tofrom/patch_ble.sh.zip
For more detailed script instructions (thanks Lem3ssie!) check out this forum: http://forums.macrumors.com/showpost.php?p=20167654&postcount=1040
UPDATE: If you updated to 10.10.1 you will need to reapply the script or download the Continuity Activation Tool and it will do it all for you.