Smart Phone Interfacing with ARM

Transcription

1 Research Paper Volume 2 Issue 8 April 2015 International Journal of Informative & Futuristic Research ISSN (Online): Smart Phone Interfacing with ARM Paper ID IJIFR/ V2/ E8/ 103 Page No Elec. & Telecomm. Subject Area Engineering Key Words GSM Module, Bluetooth Module, Portable Oscilloscope, LPC2148 Processor, ARM, Smart Phone, Android Operating System, Wireless Connectivity Azar M. Nadaf 1 Dr. S. B. Patil 2 Student Department of Electronics & Telecommunication Engineering Dr. J.J. Magdum College Of Engineering, Jaysinghpur -Maharashtra Professor Department of Electronics Dr. J.J. Magdum College Of Engineering, Jaysinghpur -Maharashtra Abstract This paper explores the implementation of Bluetooth & GSM technology in portable Oscilloscope, to give capability to handle oscilloscope quite comfortably around the places with Bluetooth & GSM module. Portable oscilloscopes currently in the market are very expensive. As we know these are heavy weight it is difficult to move.this portable oscilloscope is newly developed oscilloscope in which oscilloscope app is developed on android.because it has wireless communication it is portable. The device is equipped with a Bluetooth module to provide connectivity to a device with Bluetooth, running the Android operating system (OS), in order to display the waveforms. Android OS is selected because there are a decent number of Android device users and most of these devices satisfy the requirements of the oscilloscope s software application. Data transmitting through either Bluetooth module or GSM module depend on distance. This paper will focus on the protocol in using Bluetooth & GSM for transmitting data on a mobile using the ARM Board LPC2148 processor. 1. Introduction An oscilloscope, previously called an oscillograph, and informally known as a scope, CRO or DSO is a type of electronic test instrument that allows observation of constantly varying signal voltages, usually as a two-dimensional graph of one or more electrical potential differences using the vertical or y-axis, plotted as a function of time. Handy Oscilloscope is most important gadget in this mobile generation. Where no one is sitting at a place to finish their works. People are in hurry and needs Copyright IJIFR

2 gadgets follow their moves. People were just thinking about to carrying a gadget that will be easily carried from one place to another and work efficiently as an oscilloscope. To implement an oscilloscope using mobile instead of carrying another gadget which is a good idea Android based oscilloscope which requires nothing but a small circuitry to manage inputs and provides to android Bluetooth sensors [1]. The Android platform includes support for the Bluetooth network stack [2], which allows a device to wirelessly exchange data with other Bluetooth devices. The application framework provides access to the Bluetooth functionality through the Android Bluetooth APIs. These APIs let applications wirelessly connect to other Bluetooth devices, enabling point-to-point and multipoint wireless features. This dissertation also tries to include GSM module which send samples to android smart phone. But that will not be a real time application. This dissertation presents an oscilloscope implemented using new technology, with low power consumption. It is a Bluetooth embedded device which will capture input voltage signals and transmit them to an external device, such as a smart-phone, running the Android operating system. Since the device is wireless it can make use of the Smartphone s display and processing power. 2. Use of Bluetooth 2.1 Scope The design and implementation stage of the dissertation, involved the Bluetooth embedded hardware device implementation and the software application development for Android. The Bluetooth embedded device is a microcontroller based system. Figure.1: General Block Diagram 2.2 Bluetooth Connectivity The Android platform includes support for the Bluetooth network stack, which allows a device to wirelessly exchange data with other Bluetooth devices. The application framework provides access to the Bluetooth functionality through the Android Bluetooth APIs. These APIs let applications wirelessly connect to other Bluetooth devices, enabling point-to-point and multipoint wireless features. Using the Bluetooth APIs, an Android application can perform the following a) Scan for other Bluetooth devices b) Query the local Bluetooth adapter for paired Bluetooth devices c) Establish RFCOMM channels d) Connect to other devices through service discovery e) Transfer data to and from other devices f) Manage multiple connections 2899

3 2.3 Basic Specifications of the Bluetooth Embedded Device a)number of input channels: 2 b) Bandwidth: 2.5 khz (dual channel mode) and 5 khz (single channel mode) c) Input voltage range: V to V with 1:1 probe d) Sampling frequency: 10 khz (dual channel mode) and 20 khz (single channel mode) 2.4 Bluetooth Data Rate Limitations From research carried out it was found that data rates of 2 Mbps are not achievable with the existing software stacks implemented on the module s controller. Therefore, the approach suggested to fully utilize the Bluetooth bandwidth, was to use the module in Host Controller Interface (HCI) mode. The standard mode refers to the on-board stack running on the Bluetooth module. In HCI mode, the on-board stack is bypassed and the module is put in a state that runs the Bluetooth baseband. Therefore, the Bluetooth stack is not on the module, so it needs to be implemented on the interfacing host processor. So the module is used as a radio, performing the lower level MAC functionalities, while the application stack runs on the host processor. The hardware interface between the host processor and the module can be either UART or USB. The advantage of HCI mode is that it allows to obtain maximum throughput and also to implement custom profiles on the Bluetooth module. As we said earlier Android has nearly 80% worldwide markets share of smart phones. a) Android is an open source service. b) Android has a large community of developers writing applications. App owner can modify and improve the app making it more effective and personalized. 2.5 Data transmission sequence in dual channel mode By default, the hardware is in dual channel mode, so both input channels are sampled simultaneously. After sampling and conversion, Channel 1 (CH1) and Channel 2 (CH2) samples are converted to a byte and are immediately written to the dspic s UART buffer for transmission via Bluetooth. The even numbered and odd numbered frames contain channel 1 and channel 2 data, respectively. There is no accumulation of samples as each sample is sent soon after it is processed. In single channel mode the frames contain samples of channel 1 only. 3. Block Diagram It is a Bluetooth embedded device which will capture input voltage signals and transmit them to an external device, such as a smart-phone, running the Android operating system. Since the device is wireless it can make use of the Smartphone s display and processing power. The Bluetooth embedded device is a microcontroller based system figure 3.1 &3.2 shows a block diagram of the Bluetooth embedded device. Figure 3.1 Transmission section 2900

4 In transmission section the microcontroller is major component, for this dissertation ARM or PIC is suitable. Power supply given to ARM. Input applied will be either AC or DC, which is applied to microcontroller through interface circuit.then ADC convert this analog data to digital add send to smart phone oscilloscope through Bluetooth. Now to establish the connection between a Bluetooth based hardware and android phone. To establish a connection between both devices we need to consider android device as a master slave and another Bluetooth device as a slave to pair both devices. After establishing a connection we can send commands between both devices and start operating and receiving data for Oscilloscope device. This device communication receives data in continuous form through listener s events and collects received data into a vector form. Vector form is required to prepare graph plot on GUI. When analog input is applied to interface circuit it passes to ADC which converts analog input to digital, then microcontroller will send this data to android phone through Bluetooth module. This will be a real time application. In other way data transmission is GSM module; through this module we will send samples to android smart phone Figure 3.2: Receiver section 4. Serial Port Profile This profile defines the requirements for Bluetooth devices necessary for setting up emulated serial cable connections using RFCOMM between two peer devices. The requirements are expressed in terms of services provided to applications, and by defining the features and procedures that are required for interoperability between Bluetooth devices. 4.1 Scope The Serial Port Profile defines the protocols and procedures that shall be used by devices using Bluetooth for RS232 (or similar) serial cable emulation. The scenario covered by this profile deals with legacy applications using Bluetooth as a cable replacement, through a virtual serial port abstraction (which in itself is operating system-dependent). 4.2 Bluetooth Profile Structure In Figure the Bluetooth profile structure and the dependencies of the profiles are depicted. A profile is dependent upon another profile if it re-uses parts of that profile, by implicitly or explicitly referencing it. Dependency is illustrated in the figure: a profile has dependencies on the profile(s) in which it is contained directly and indirectly. 2901

5 Figure 4.1 Bluetooth Profile Structure 5. Results Figure 5.1 Received data on Smartphone Figure 5.2 Received data on Smartphone through GSM Modem 6. Conclusion By interfacing of ARM modem to Bluetooth modem we received voltage in digital format on spp application of smart phone.& By interfacing of ARM modem to GSM modem we received voltage in message format on smart phone.which shoes mobile number on which message is displayed & message in milivolt. 2902

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