read_dht.py

#!/usr/bin/env python
# This file is part of HoneyPi [honey-pi.de] which is released under Creative Commons License Attribution-NonCommercial-ShareAlike 3.0 Unported (CC BY-NC-SA 3.0).
# See file LICENSE or go to http://creativecommons.org/licenses/by-nc-sa/3.0/ for full license details.

import Adafruit_DHT
import os
os.environ['PYTHON_EGG_CACHE'] = '/usr/local/pylons/python-eggs'

def measure_dht(ts_sensor):
    fields = {}

    try:
        pin = int(ts_sensor["pin"])
        dht_type = int(ts_sensor["dht_type"])

        # setup sensor
        if dht_type == 2302:
            sensorDHT = Adafruit_DHT.AM2302
        elif dht_type == 11:
            sensorDHT = Adafruit_DHT.DHT11
        else:
            sensorDHT = Adafruit_DHT.DHT22

        try:
            humidity, temperature = Adafruit_DHT.read_retry(sensorDHT, pin)

            # Create returned dict if ts-field is defined
            if 'ts_field_temperature' in ts_sensor and temperature is not None:
                if 'offset' in ts_sensor and ts_sensor["offset"] is not None:
                    temperature = temperature-float(ts_sensor["offset"])
                # limit to 2 digits
                temperature = float("{0:.2f}".format(temperature))
                fields[ts_sensor["ts_field_temperature"]] = temperature
            if 'ts_field_humidity' in ts_sensor and humidity is not None:
                # limit to 2 digits
                humidity = float("{0:.2f}".format(humidity))
                fields[ts_sensor["ts_field_humidity"]] = humidity

        except Exception as e:
            print("Reading DHT failed (DHT: " + str(dht_type) + "/" + str(sensorDHT) +", GPIO: " + str(pin) + "): " + str(e))

    except Exception as e:
        print("DHT missing param: " + str(e))

    return fields