lập trình bluetooth sharing

Dynamic Bluetooth File Sharing With Cellular Devices Steve Brar George Chen Michael Hair Jon Wagoner Project Goals • • • • • • • Establishing a Bluetooth connection Download application software to client Look up existing shared directory File Browsing Functionality Connection Identification Descriptions of Peripheral Nodes Download Status Software/Hardware • Simulation Environment - Java J2ME SDK 2.2.3 – http://developer.sonyericsson.com/site/global/docstools/java/p_j ava.jsp – http://developer.sonyericsson.com/getDocument.do?docId=65256 • • • • • Modified Bluetooth Plug-in – Sony Ericsson JSR82 Java SE Development Kit (JDK 1.4.2) Windows Script 5.6 Devices – Sony Ericsson w600i Multimedia Phone Testing/Emulator Environment – Personal Computer Cellular Emulation and directly on the Sony Ericsson w600i Overview • • • • • Bluetooth Protocol Stack Mobile Device Information Profile (MIDP) Program Hierarchy Live Demo Final Thoughts Bluetooth Protocol Stack Bluetooth Discovery • Device needs to device discovery and service discovery • Device discovery: methods • Inquiry: • startInquiry() • retrieveDevices() • cancelInquiry() • Callbacks: • devicesDiscovered() • inquiryCompleted() Bluetooth Discovery Bluetooth Discovery • Service Discovery: Methods • Inquiry: • selectServices() == searchServices() • cancelServiceSearch() • Callbacks: • servicesDiscovered() • serviceSearchCompleted() • Needs to implement DiscoveryAgent and DiscoveryListner class • Agent looks for services and devices • Listener implements callback mechanisms Bluetooth Discovery RFCOMM vs. OBEX • RFCOMM • Better choice when you want to send/receive stream data • OBEX • Allows one to send not only data, but also send context or metadata about the payload. • Our project deals with sharing music files, so we chose OBEX! (that’s the red pill in case you didn’t know) Semantics of OBEX • OBEX is not native to Bluetooth • Derived from IrDA (Infrared Data Association) • Works not only through Bluetooth, but also other transport protocols (TCP/UDP) OBEX operations • An OBEX operation is an interaction between the server and the client • The client sends commands to server • Server handles command • Commands available • • • • CONNECT GET PUT … MIDP • Stands for Mobile Information Device Profile – Profile: set of standard APIs that support narrower category of devices • Part of J2ME specification • Specification for APIs to support broad portability and deployment – – – – Application delivery and billing End-to-end secure transaction (e.g. https) Signing model and security model … a lot more! • Currently version 2.0, but is backward compatible MIDP Architecture • From the high level point of view, the lowest level is the MID, which is the device hardware. The highest level is all the possible applications that can run on a MID • CLDC: VM and associated libraries MIDP Security • Sensitive Operations – javax.microedition.io.connector • Protection Domains – Trusted/Untrusted MIDlets • Signing MIDlet Suites – Certificates – Code Verification CLDC • Stands for Connection Limited Device Configuration – Configuration: most basic set of libraries and VM features • Just like MIDP, it is also part of J2ME • CLDC is aimed towards resource-constraint devices that have networking capability. Live Demo • Demo • About Emulators – Availability – Issues Program Hierarchy DemoMIDlet • Creates the top-level interface to allow the user to select either the Server or Client • Creates the appropriate Client or Server object GUIMusicServer • Merely provides the interface to the user and the actual device to select features of the BTMusicServer • Also establishes the connection between the GUI and the device • Allows the user to select which music files to share for other clients to download 10 BTMusicServer • Makes the device discoverable by creating the Bluetooth OBEX server • Adds the music server UUID to the service record • Broadcasts the shared filenames • Will send the shared music file to the client upon the client’s request GUIMusicClient • Provides the interface for the user to select which file (shared on the server) to download • Will create the new file and save it in a specific location on the device • Provides search error notification 11 BTMusicClient • Actively searches for Bluetooth servers that are discoverable • Upon discovering a server device, will connect to that device and retrieve list of shared music files • Will download the music file from the server via OBEX Challenges • Setting up the Emulator properly • Signing the MIDlet • Having proper permissions for files • J2ME specific function objects • File transfer • Finding devices able to accept open source modification: • MIDP 2.0 compatible phones • Security certificates accepted 12 Our Pitfalls • OBEX vs. RFComm Software Limitations • Data Connectivity Compatibility to upload files to cellular devices • SDK/Project compilation • Carrier protected access to the MIDlet network functions Future Considerations • Power Consumption • Enhanced On-the-Fly Connection/File Transfer Applications • Continuous Device Discovery during file transfers • PC-to-Cellular Device audio streaming • Advanced lookup algorithms • Multiple Simultaneous File Downloads • Cross Platform Compatibility • Security 13 [...]...BTMusicServer • Makes the device discoverable by creating the Bluetooth OBEX server • Adds the music server UUID to the service record • Broadcasts the shared filenames • Will send the shared music file to the client upon the client’s request GUIMusicClient • Provides... which file (shared on the server) to download • Will create the new file and save it in a specific location on the device • Provides search error notification 11 BTMusicClient • Actively searches for Bluetooth servers that are discoverable • Upon discovering a server device, will connect to that device and retrieve list of shared music files • Will download the music file from the server via OBEX Challenges . 1 Dynamic Bluetooth File Sharing With Cellular Devices Steve Brar George Chen Michael Hair Jon Wagoner Project Goals • Establishing a Bluetooth connection • Download application. Ericsson w600i Overview • Bluetooth Protocol Stack • Mobile Device Information Profile (MIDP) • Program Hierarchy •Live Demo • Final Thoughts 3 Bluetooth Protocol Stack Bluetooth Discovery • Device. retrieveDevices() • cancelInquiry() • Callbacks: • devicesDiscovered() • inquiryCompleted() 4 Bluetooth Discovery Bluetooth Discovery • Service Discovery: Methods • Inquiry: • selectServices() == searchServices() •