Communication PIC-Microcontroller Lab Course by JAOM Center, Feb. 2013Bluetooth Module Instructor: Mohsen Sarakbi
Definition Bluetooth is a specification (IEEE 802.15.1) for the use of low-power radio communications to link phones, computers and other network devices over short distances without wires. The name Bluetooth is borrowed from Harald Bluetooth, a king in Denmark more than 1,000 years ago. First specification released in July 1999
General Specification Short range wireless connectivity. Low power consumption Automatic recognition.
General Specification Bluetooth technology was designed primarily to support simple wireless networking of personal consumer devices and peripherals, including cell phones, and wireless headsets. Wireless signals transmitted with Bluetooth cover short distances, typically up to 10 meters. Bluetooth devices generally communicate at less than 1 Mbps. Bluetooth networks feature a dynamic topology called a piconet or personal area networks (PAN), up to 8 devices
Radio Specification• The Bluetooth system is operating in the 2.4 GHz ISM (Industrial Scientific Medicine) band. The regulatory range of this frequency band is 2.400 – 2.4835 GHz.• The Bluetooth radio accomplishes spectrum spreading by in 79 hops displaced by 1 MHz.• Radio modulation uses GFSK.
Bluetooth vs. Wi-Fi Although the Bluetooth standard utilizes the same 2.4GHz range as Wi-Fi, Bluetooth technology is not a suitable Wi-Fi replacement. Compared to Wi-Fi, Bluetooth networking is: o Much slower o A bit more limited in range o Supports many fewer devices.
Bluetooth Classes Three classes of Bluetooth devices o Class 3 radios: have a range of up to 1 meter o Class 2 radios: most commonly found in mobile devices, have a range of 10 meters o Class 1 radios: used primarily in industrial use cases, have a range of 100 meters.
Link Manager Protocol (LMP) Responsible for link set-up between devices, including security functions : o Authentication o Encryption Pairing: o Using a shared secret (PIN), exchange random number to form key.
Bluetooth Module Wireless TTL Transceiver Module
AT Commands AT Command Actions Return AT Testing the connection OK AT+BAUDx Changing the default baud rate OKbaudrate AT+NAMEname Changing default name OKname AT+PINpin Changing default password OKpin
Lab BT to PC as Serial port connection Test AT - Commands Check outputs BT to PIC Test AT - Commands Application blinking LED number + LCD PC to BT by software Moving car Mobile to PIC by BT MCU App Moving car app, Controller app, BT SPP app Check output by LCD or PC