wind.py

import RPi.GPIO as GPIO
from gpiozero import MCP3008
from database import database
import math
from apscheduler.schedulers.background import BackgroundScheduler

class wind:
    def __init__(self, db_file, anemometer_pin=None, anemometer_radius_cm = 9.0):
        scheduler = BackgroundScheduler()
        self.db_file = db_file
        self.anemometer_pin = anemometer_pin
        self.anemometer_radius_cm = anemometer_radius_cm
        self.adc = MCP3008(channel=0)
        self.spin_amount = 0
        self.loop_interval = 5
        self.wind_speed = None
        try:
            GPIO.setmode(GPIO.BCM)
            GPIO.setup(self.anemometer_pin, GPIO.IN, pull_up_down=GPIO.PUD_UP)
            GPIO.add_event_detect(self.anemometer_pin, GPIO.FALLING, callback=self.register_spin)
            scheduler.add_job(self._calculate_wind_speed, 'interval', seconds=self.loop_interval)
            scheduler.start()
        except:
            print('Error while setting up GPIO for wind measurements')

    def _calculate_wind_speed(self):
        circumference_cm = (2 * math.pi) * self.anemometer_radius_cm
        rotations = self.spin_amount / 2.0
        distance_km = (circumference_cm * rotations) / 100000.0

        km_per_sec = distance_km / self.loop_interval
        km_per_hour = km_per_sec * 3600

        self.wind_speed = km_per_hour
        self.reset_anemometer_spins()
        self._write_wind_to_db()


    def register_spin(self, pin):
        self.spin_amount += 1

    
    def reset_anemometer_spins(self):
        self.spin_amount = 0


    def _get_wind_direction(self):
        pass


    def _write_wind_to_db(self):
        database(self.db_file).set_data('INSERT INTO wind VALUES ({0}, {1}, {2}, {3})'.format(None, None, self.wind_speed, 'km/h'))