Hello hackers, today I successfully tested my Bluetooth communication module (which I bought from a random eBay seller). The part number of this Bluetooth module is HC-05 and it connects directly to a 4-pin connector on my Freescale FRDM-K64F dev board, being supplied with 3.3V. 

I am connecting my board to a PC via USB-serial (and using a terminal on PC) and the Bluetooth module to an Android cellphone, with an app called Blueterm. The code used for testing it is a simple "mirror": it gets info I type on the Android App and sends it to the PC terminal, and the other way around as well (text typed on PC is sent to the App on Android cellphone). The code I used is available on mBed platform and on my GitHub (links on the left side of this page).

Schematic drawing of this connection can be seen below: 

Next step will be testing the RFID tag reader and HC-05 Bluetooth together, reading cards and sending info to the cellphone and PC.