DHT11 & DHT22 Sensor Temperature and Humidity Phyton Examples

Old and deprecated code, BUT easy to use.

https://github.com/adafruit/Adafruit_Python_DHT

Installing

Dependencies

For all platforms (Raspberry Pi and Beaglebone Black) make sure your system is able to compile and download Python extensions with pip:

On Raspbian or Beaglebone Black's Debian/Ubuntu image you can ensure your system is ready by running one or two of the following sets of commands:

Python 2:

sudo apt-get update
sudo apt-get install python-pip
sudo python -m pip install --upgrade pip setuptools wheel

Python 3:

sudo apt-get update
sudo apt-get install python3-pip
sudo python3 -m pip install --upgrade pip setuptools wheel

Install with pip

Use pip to install from PyPI.

Python 2:

sudo pip install Adafruit_DHT

Python 3:

sudo pip3 install Adafruit_DHT

Compile and install from the repository

First download the library source code from the GitHub releases page, unzipping the archive, and execute:

Python 2:

cd Adafruit_Python_DHT
sudo python setup.py install

Python 3:

cd Adafruit_Python_DHT
sudo python3 setup.py install

You may also git clone the repository if you want to test an unreleased version:

git clone https://github.com/adafruit/Adafruit_Python_DHT.git

---

Examples

#!/usr/bin/python
import sys
import Adafruit_DHT
import time
from datetime import date
from datetime import datetime

while True:

  humidity, temperature = Adafruit_DHT.read_retry(22, 27)
#  print 'time ', datetime.today().strftime("%d/%m/%Y %H:%M:%S")
  print  ' ', datetime.today().strftime("%d/%m/%Y %H:%M:%S") + ' Temp: {0:0.1f} C  Humidity: {1:0.1f} %'.format(temperature, humidity) 
  time.sleep(5)

---

#!/usr/bin/python
# Copyright (c) 2014 Adafruit Industries
# Author: Tony DiCola

# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:

# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.

# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.
import sys

import Adafruit_DHT


# Parse command line parameters.
sensor_args = { '11': Adafruit_DHT.DHT11,
                '22': Adafruit_DHT.DHT22,
                '2302': Adafruit_DHT.AM2302 }
if len(sys.argv) == 3 and sys.argv[1] in sensor_args:
    sensor = sensor_args[sys.argv[1]]
    pin = sys.argv[2]
else:
    print('Usage: sudo ./Adafruit_DHT.py [11|22|2302] ')
    print('Example: sudo ./Adafruit_DHT.py 2302 4 - Read from an AM2302 connected to GPIO pin #4')
    sys.exit(1)

# Try to grab a sensor reading.  Use the read_retry method which will retry up
# to 15 times to get a sensor reading (waiting 2 seconds between each retry).
humidity, temperature = Adafruit_DHT.read_retry(sensor, pin)

# Un-comment the line below to convert the temperature to Fahrenheit.
# temperature = temperature * 9/5.0 + 32

# Note that sometimes you won't get a reading and
# the results will be null (because Linux can't
# guarantee the timing of calls to read the sensor).
# If this happens try again!
if humidity is not None and temperature is not None:
    print('Temp={0:0.1f}*  Humidity={1:0.1f}%'.format(temperature, humidity))
else:
    print('Failed to get reading. Try again!')
    sys.exit(1)