I have some code (shown below) which turns the Raspberry Pi into a datalogger. I use GPIO.add_event_detect to detect the date and time that a square wave signal changes state. This data is then saved to a CSV file continuously as each state change is detected. However if I turn the Raspberry Pi off or stop the program from running, when I then turn it back on again the previous CSV file is overwritten by a new file. Does anyone know how I could create a new CSV file every time I reboot the program/Pi?
import RPi.GPIO as GPIO
import datetime
from datetime import timedelta
import time
from time import sleep
import csv
from csv import writer
# endTime = datetime.datetime.now() + datetime.timedelta(seconds=60)
def my_callback(channel):
data_writer([GPIO.input(40), datetime.datetime.now()]) # writes the detected
# edge event to a CSV file with columns of rise/fall and the date & time of detection
if __name__ == '__main__':
GPIO.setmode(GPIO.BOARD) # set up GPIO numbering (BOARD = physical pins on Pi)
GPIO.setup(40, GPIO.IN) # set physical pin 40 as input
# create CSV file to write edge detection data to called Datalogger, with data on new line
with open('/media/pi/KINGSTON/datalogger.csv', 'w', newline='') as Datalogger:
data_writer = writer(Datalogger)
data_writer.writerow(["Edge type", "Date & Time"]) # create headers in CSV file
GPIO.add_event_detect(40, GPIO.BOTH, callback=my_callback) # edge detection function
# detects both rise and fall in signal on pin 40, then runs my callback
while True:
# main program loop here - loops detection of edges then runs my callback
# if datetime.datetime.now() >= endTime:
# break
time.sleep(0.001)
# exit()
