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from gpiozero import Button
import time
import math
import statistics
anem = Button(5) # setup GPIO 5 as a button
storeSpeeds = []
windCount = 0 # counts half-rotations
radius_cm = 9.0 # radius of anemometer
circumference_cm = (2 * math.pi) * radius_cm
windInterval = 5 # how often to report speed
cmInKm = 100000.0
secsInHour = 3600
anemFactor = 1.18 # anemometer factor is the result of wind energy lost due to the arms turning
# every half rotation, add one to count
def spin():
global windCount
windCount += 1
# calculate wind speed
def calculateSpeed(timeSec):
global windCount
global circumference_cm
rotations = windCount / 2.0
# calculate distance travelled by anemometer in km
distKm = circumference_cm * rotations / cmInKm
speed = ((distKm / timeSec) * secsInHour) * anemFactor
return speed
def resetWind():
global wind_count
wind_count = 0
anem.when_pressed = spin
# Loop to measure wind speed and report at 5 second intervals
while True:
startTime = time.time()
while time.time() - startTime <= windInterval:
resetWind() # reset count for next 5 second run
time.sleep(windInterval)
#finalSpeed = calculateSpeed(windInterval)
storeSpeeds.append(calculate(windInterval)) # store average speed over 5 seconds
windGust = max(storeSpeeds) # maximum gust
windSpeed = statistics.mean(storeSpeeds) # running average wind speed
print(windSpeed, "km/h", windGust, "km/h")
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