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Kategorie: Diplomové, bakalářské práce |
Tento dokument chci!
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.
At first program clear max and put min high value.
At the end test value correct range. 12500 clock cycles, timer has lower value than 15000, digital
input interrupt could happened because received noise some reflected signal.9 ADC peak peak function
The adc_peaktopeak function called after gpio_post_int from main function.
The function has adc_array address input argument.4.11: Flowchart GPIO post interrupt function
4. Values below correspond
with 170 m/s. There are some correction
of this error later. There are local variable on
the beginning. Actually this value
can from 2500 5000 higher because another details.8 GPIO post interrupt function
The gpio_post_int function called from main after adc_sample function. every step takes one value from adc_array and
store adc_value local variable. flag fulfill
this condition, program exit from function.
Illustration 4. we
multiply this number 3,3 and divided 1000, had peak peak voltage of
received signal. It
calculate difference between maximum and minimum sampled sequence. Program returns measured time and exit. Digital input interrupt pin level disabled and flag set next
state, X_WIND_CALC Y_WIND_CALC. Than actual adc_value tested higher than max
28
. sampled 128 values,
program stay loop for 128 cycles.
After that get value from timer and calculate measured time as
a complement timer_load_set.4. were discounting from 31250 (2,5 ms) and signal
takes 1,5 spread between sensor, has measure 18750. Then tested flag set X_PWM Y_PWM state. This can happen for too low measured time. In
that case set flag for next measurement. first is
defined variable. Then tested flag parameter let know, which PWM generator
has switch off.4
