data_collection.py

# -*- coding: utf-8 -*-
"""
Created on Mon Nov 22 20:50:18 2021

@author: Mc Zie
"""
import datetime
import time
import board
import busio
i2c = busio.I2C(board.SCL, board.SDA)
import csv
import adafruit_ads1x15.ads1015 as ADS
#import adafruit_ads1x15.ads1115 as ADS

from adafruit_ads1x15.analog_in import AnalogIn


slope = 1.48; #slope from linear fit
intercept = -1.56 # intercept from linear fit

ads = ADS.ADS1015(i2c)

chan = AnalogIn(ads, ADS.P0)
#voltage=chan.voltage

while True: 
    try: 
        voltage = round((chan.voltage),2)
        print( 'voltage:')
        print(f'{chan.voltage} Volt')
        
        vol_water_cont = ((1.0/chan.voltage)*slope)+intercept #calc of theta_v (vol. water content)
        vol_water_cont= round((vol_water_cont),2)
        print(" V, Theta_v: ")
        print(f'{vol_water_cont} cm^3/cm^3')
        
        if vol_water_cont>-0.40:
            print('wet')
        else: 
            
            print('dry')
        
        def get_voltage(): 
            
            voltage = round((chan.voltage),2) 
           
            voltage = str(voltage) 
            
            return(voltage)
        
        def get_humidity():
            
            humidity = vol_water_cont
            humidity= round((humidity),2)
            
            humidity = str(humidity) 
           
            return(humidity)
        
        def date_now():
           today = datetime.datetime.now().strftime("%Y-%m-%d")
           today = str(today)
           return(today)
        
        def time_now():
            
            now = datetime.datetime.now().strftime("%H:%M:%S")
            now = str(now)
            return(now)
        
        def get_humidity_binary():
            
            if vol_water_cont>-0.40:
                
                return str('wet')
            else: 
                return str('dry') 
           
        
        def write_to_csv():
            
            #the a is for append, if w for write is used then it overwrites the file
            with open('/home/pi/sensor_readings.csv', mode='a') as sensor_readings: 
                
                sensor_write = csv.writer(sensor_readings, delimiter=',', quotechar='"', quoting=csv.QUOTE_MINIMAL)
                write_to_log = sensor_write.writerow([date_now(),time_now(),get_voltage(), get_humidity(),get_humidity_binary()])
                return(write_to_log) 
            
        print( write_to_csv())
        
        time.sleep(1) 
        
    except KeyboardInterrupt: 
        break 
    except IOError: 
        print ("Error")