Datetime issue

[DareDrop]

I am using a DHT22 sensor to log temp and humidity and save it to a csv file.

What I need is a date for each read in this format MM/DD/YYYY

And the time as HH:MM:SS

Been try to work this out, have looked and at ref and still can not get it.

Pls help

Thanks

[DougieLawson]

What software are you using to read the sensor? What language is it written in? Where did you download it from?

[DareDrop]

Sorry should have put that in, my bad.

Raspi 3
Raspbain Stetch updated Upgraded
Python

[DougieLawson]

Post your python code in [code]... your stuff goes here ...[/code] tags. As that makes the difference between

from datetime import datetime

very_True=True

iso_format=True
silly_american_fmt=very_True

date_str = datetime.now()
yyyy_mm_dd = datetime.strftime(date_str, "%Y-%m-%d %H:%M:%S")
american_fmt = datetime.strftime(date_str, "%m/%d/%Y %H:%M:%S")

if silly_american_fmt == True:
print (american_fmt)
else:
print (yyyy_mm_dd)

And

Code: Select all

from datetime import datetime

very_True=True

iso_format=True
silly_american_fmt=very_True

date_str = datetime.now()
yyyy_mm_dd = datetime.strftime(date_str, "%Y-%m-%d %H:%M:%S")
american_fmt = datetime.strftime(date_str, "%m/%d/%Y %H:%M:%S")

if silly_american_fmt == True:
  print (american_fmt)
else:
  print (yyyy_mm_dd)

[DareDrop]

Post your python code in

Code: Select all

... your stuff goes here ...

tags. As that makes the difference between

from datetime import datetime

very_True=True

iso_format=True
silly_american_fmt=very_True

Not sure what this is, would you explain pls

date_str = datetime.now()
yyyy_mm_dd = datetime.strftime(date_str, "%Y-%m-%d %H:%M:%S")
american_fmt = datetime.strftime(date_str, "%m/%d/%Y %H:%M:%S")

This is the format get set up Date in 2 forms, OK

if silly_american_fmt == True:
print (american_fmt)
else:
print (yyyy_mm_dd)

This is the print statement OK

[bensimmo]

He is showing you and example between using 'code tags' and not using them, it's one of the format option when posting on here.


He wants you to post your code.

[DareDrop]

Code: Select all

import time
import datetime
import csv
import sys

import Adafruit_DHT

sensor = Adafruit_DHT.DHT22
pin = 4


with open('dht.csv', 'w') as csv_file:
    dhtwriter=csv.writer(csv_file)
    dhtwriter.writerow(['Time', 'Tempemperature (F)', 'Humidity (%)'])
    while True:
        reading_time = datetime.datetime.now()
        humidity, temperature = Adafruit_DHT.read_retry(sensor, pin)
        if humidity is not None and temperature is not None:
            time_now = datetime.datetime.now()
            Tempemperature = ('Temp={0:0.1f}*C')
            print('Time: {0} Tempemperature: {1} Humidity: {2}'.format(time_now, temperature, humidity))
            dhtwriter.writerow([time_now, temperature, humidity])
            time.sleep(600)

Here is the code.

[pcmanbob]

This shows you how to get the date and time or just the time.

Code: Select all

import time

datetime = time.strftime("%d-%m-%Y %H:%M:%S")
print datetime

time = time.strftime("%H:%M:%S")

print time

results look like this
31-08-2017 22:47:36
22:47:36

[DougieLawson]

Change these lines

Code: Select all

        if humidity is not None and temperature is not None:
            time_now = datetime.datetime.now()
            Tempemperature = ('Temp={0:0.1f}*C')

to

Code: Select all

        if humidity is not None and temperature is not None:
            time_now = datetime.datetime.now()
            time_now = time_now.strftime("%m/%d/%Y %H:%M:%S")
            Tempemperature = ('Temp={0:0.1f}*C')

NOTE that ISO dates (2017-09-01) naturally sort in date order. American dates (09/01/2017) need special handing to sort correctly (Excel can do that, because it converts your format to a day number internally).

BTW, if you want temps in °F rather than °C change

Code: Select all

        humidity, temperature = Adafruit_DHT.read_retry(sensor, pin)
        

to

Code: Select all

        humidity, temperature = Adafruit_DHT.read_retry(sensor, pin)
        temperature = (temperature*1.8)+32

[DareDrop]

Code: Select all

>>> import time
>>> datetime = time.strftime("%d-%m-%Y %H:%M:%S")
>>> print datetime
SyntaxError: Missing parentheses in call to 'print'

>>> print (datetime)
31-08-2017 20:47:23

>>> time = time.strftime("%H:%M:%S")
>>> print time
SyntaxError: Missing parentheses in call to 'print'

>>> print(time)
20:49:44

This works with the change to the print statement.

Thanks

[DougieLawson]

That's a feechur of python2 code being run with python3.

[DareDrop]

import time
import datetime
import csv
import sys

import Adafruit_DHT

sensor = Adafruit_DHT.DHT22
pin = 4

with open('dht.csv', 'w') as csv_file:
dhtwriter=csv.writer(csv_file)
dhtwriter.writerow(['Date', 'Time', 'Tempemperature (F)', 'Humidity (%)'])
while True:
reading_time = datetime.datetime.now()
humidity, temperature = Adafruit_DHT.read_retry(sensor, pin)
if humidity is not None and temperature is not None:
sensor_date = time.strftime("%m-%d-%Y")
sensor_time = time.strftime("%H:%M:%S")
Tempemperature = ('Temp={0:0.1f}*C')
Humidity = ('Humidity={1:0.1f}%')
print('Date: {0} Time: {1} Tempemperature: {2} Humidity: {3}'.format(sensor_date,
sensor_time, temperature, humidity))
dhtwriter.writerow([sensor_date, sensor_time, temperature, humidity])
time.sleep(4)

New code

pi@raspisensor:~/Adafruit_Python_DHT/examples $ sudo python simpletest_h.py
Date: 08-31-2017 Time: 21:44:19 Tempemperature: 23.7000007629 Humidity: 44.5
Date: 08-31-2017 Time: 21:44:24 Tempemperature: 23.6000003815 Humidity: 44.9000015259
Date: 08-31-2017 Time: 21:44:28 Tempemperature: 23.6000003815 Humidity: 44.9000015259
Date: 08-31-2017 Time: 21:44:33 Tempemperature: 23.6000003815 Humidity: 44.9000015259
Date: 08-31-2017 Time: 21:44:38 Tempemperature: 23.6000003815 Humidity: 44.9000015259
Date: 08-31-2017 Time: 21:44:45 Tempemperature: 23.6000003815 Humidity: 44.9000015259

output

now i just need to format the numbers.

Thanks