import serial
from datetime import datetime
import csv

#Open a csv file and set it up to receive comma delimited input
logging = open('logging.csv',mode='a')
writer = csv.writer(logging, delimiter=",", escapechar=' ', quoting=csv.QUOTE_NONE)

#Open a serial port that is connected to an Arduino (below is Linux, Windows and Mac would be "COM4" or similar)
#No timeout specified; program will wait until all serial data is received from Arduino
#Port description will vary according to operating system. Linux will be in the form /dev/ttyXXXX
#Windows and MAC will be COMX. Use Arduino IDE to find out name 'Tools -> Port'
ser = serial.Serial('/dev/ttyACM0')
ser.flushInput()

#Write out a single character encoded in utf-8; this is defalt encoding for Arduino serial comms
#This character tells the Arduino to start sending data
ser.write(bytes('x', 'utf-8'))


while True:
    #Read in data from Serial until \n (new line) received
    ser_bytes = ser.readline()
    print(ser_bytes)
    
    #Convert received bytes to text format
    decoded_bytes = (ser_bytes[0:len(ser_bytes)-2].decode("utf-8"))
    print(decoded_bytes)
    
    #Retreive current time
    c = datetime.now()
    current_time = c.strftime('%H:%M:%S')
    print(current_time)
    
    #If Arduino has sent a string "stop", exit loop
    if (decoded_bytes == "stop"):
         break
    
    #Write received data to CSV file
    writer.writerow([current_time,decoded_bytes])
            
# Close port and CSV file to exit
ser.close()
logging.close()
print("logging finished")