| As a professional communication device,the intercom has an important role in many fields.However,the high cost and inconvenient carrying characteristics make it difficult to popularize to common users.A development method of an external wireless communication device based on Android phones which can realize the intercom function is studied in this thesis to solve this problem.The major contents are:1.The hardware scheme of the device is studied,and the block diagram of the system scheme is provided,as well as detailed device selection for each module in the block diagram is made.The details of similar devices are compared and researched,and eventually the wireless communication module based on SI4463 to realize the wireless communication function is chosen.Meanwhile,the wireless signal band is 433 MHz and the modulation mode is 2GFSK.Besides,the cell phone chooses USB interface as the access interface of external devices,and FT2232 HL is selected to convert the USB interface signal of the cell phone into SPI interface signal to achieve the data interaction between the cell phone and the wireless communication module.2.The design of schematic and PCB diagram of the device,as well as process and solder the single board are studied.In this thesis,the requirements of each chip manual of the device are summarized,and the precautions of schematic design are organized,and the schematic design details are described in detail.Moreover,it not only concludes the design rules and design methods of the device PCB diagram in detail,but also shows the final design results and the actual product.3.The overall architecture and design methodology of the device application software are studied.Furthermore,the software requirement specification is analyzed,the software structure and hierarchy are divided,the functions of each module and the interfaces between modules are determined,the implementation principles and methods of the USB to SPI driver and wireless module driver are emphasized,so as to complete the driver layer coding and debugging.In addition,this thesis adequately demonstrates and discusses these research results,which introduces the application software interface and workflow design methods.4.The hardware parameters,software functions and system performance of the device are tested completely.Additionally,the hardware supply voltage and important signal waveforms are measured and presented,and the software functions are tested completely,and all operations are traversed.Finally,it verifies that all results are correct.The maximum transmission power of the device is 20 d Bm,the reception sensitivity is-100 d Bm,and the maximum power consumption is 0.25 W.Moreover,the measured maximum communication distance is 2.13 km,with all the tested indicators meeting the specifications.Through the completion of these work,an Android phones' external wireless communication device is designed and manufactured.It can assist Android phones to achieve intercom function,and all performance indexes can meet the requirements.It only needs a simple easy device plugged into the phone to realize the communication intercom function without depending on the operator network,thus It not's only has the advantages of low cost,easy to carry,simple to use,etc,but also has the characteristics of zero cost,adaptability,high independence,security factor,and other,so it is very suitable for ordinary consumer users to use as a close wireless communication.Thus it promoted the popularity of intercom among ordinary users. |
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