Ultrazvukový anemometr

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Práce popisuje principy a problémy při realizaci ultrazvukového anemometru. Je popsán princip výpočtu rychlosti větru a následné korekce výpočtu. Pro realizaci jsou využity ultrazvukové sensory a microcontrolér ARM Cortex-M3. Práce se zabývá generováním PWM signálu, jeho analogovou filtrací, zesílením a odvysíláním. Na přijímací straně jeto nízkonapěťový zesilovač a komparátor. Vyvíjený kód je popsán pomocí vývojového diagramu.

Vydal: FEKT VUT Brno Autor: Michael Dvořácek

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Their behavior controlled with flag global variable with its definitions for every value. It’s divided into sections and functions was illustrated above. Constant variable timer_load_set used to set time for timer interruption. Code continue with a component functions. After digital input port interruption ADC sample function called. It let know every time what was done and what has done.1 Header files, Global variable and Defines Included header files are chosen for used peripherals and microcontroller. From time time function calculate temperature called. also includes example use every peripherals.2 TI. Variable flag has defined all its states above. permit us using drive Stellaris driver API functions.3 Code development Code was developed Code composer studio 4. The rest are function calculate peak peak value from ADC sequence, function make averages peak peak values and wind calculation function. Flowchart take account whole code inside anemometer file, which was created for this application. CCS was installed from kit included CD. All orders, processes and functions are accompanied with lot comments. Behind that while loop start. Variable adc_array is used save here samples from converter.4. Then interrupt handler functions can found.4 Flowcharts To describe how works our anemometer flowchart was created. All code was written into anemometer file. It’s divided few section the beginning. First function preparing PWM for measurement chosen axis. Its value 31250 refers 2,5 with 12,5 MHz clock speed. These conditions test flag global variable and inside each concretes functions are called. There are few condition inside. 4. Then function capture time from timer called. 21 . Below interrupt handler functions the rest of functions can found. [15] Within development code Stellaris peripheral driver library user's guide was great aid [14]. the beginning the main are local variables with calling initialization function. All them are called from main function, where the program starts. After release notes include files, global variable with its defines can found. also contain programming examples, driver libraries and and header files, which form application programming interface API.4. On the bottom the code main function with its infinite while loop. Then after timer interrupt function inform that measurement hasn’t done and sets flag start again. 4. Every part will be described separately below. contain basic description all peripherals programming API. After this initialization main function called. For creation this diagrams LibreOffice Draw was used. the beginning initialization functions takes place