07.09.2016 09:37:19
В интернете масса статей о том, как получить значение температуры и влажности с DHT22 на Rraspberry pi 3 (или более ранних). Но проблема в том, что большинство их или устарело (ссылаются на уже не существующие наработки) или у меня не заработало.

Библиотека для работы с DHT - Adafruit Python DHT

Установка:

 
apt-get install build-essential python-dev
git clone https://github.com/adafruit/Adafruit_Python_DHT.git
cd Adafruit_Python_DHT
python setup.py install

Скрипт для получения данных:

 
#!/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] GPIOpin#'
    print 'example: sudo ./Adafruit_DHT.py 2302 4 - Read from an AM2302 connected to GPIO #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)

Использование (у файла должны быть права на исполнение):

 
./Adafruit_DHT.py 22 17

Общий вид:

 
./Adafruit_DHT.py [11|22|2302] GPIOpin

Скрытый текст


Тэги: raspberry pi 3

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