Publish DHT22 readings to MQTT broker

dht22-mqtt.py

# Original script from https://learn.adafruit.com/dht-humidity-sensing-on-raspberry-pi-with-gdocs-logging/python-setup

# SPDX-FileCopyrightText: 2021 ladyada for Adafruit Industries
# SPDX-License-Identifier: MIT

# RUN:
# BROKER=localhost python read.py

import time
import board
import adafruit_dht
import requests
import os
import paho.mqtt.client as paho

broker = os.environ['BROKER']
port=1883

# Initial the dht device, with data pin connected to:
dhtDevice = adafruit_dht.DHT22(board.D4)

# you can pass DHT22 use_pulseio=False if you wouldn't like to use pulseio.
# This may be necessary on a Linux single board computer like the Raspberry Pi,
# but it will not work in CircuitPython.
# dhtDevice = adafruit_dht.DHT22(board.D18, use_pulseio=False)

mqtt_client=paho.Client(client_id="pluto-dht22")

def on_connect(client, userdata, flags, rc):
    print("Connected: {}".format(paho.connack_string(rc)))

def on_disconnect(client, userdata, rc):
    print("Disonnected: {}".format(paho.connack_string(rc)))

mqtt_client.on_connect = on_connect
mqtt_client.on_disconnect = on_disconnect
mqtt_client.connect_async(broker,port)
mqtt_client.loop_start()

while True:
    try:
        print("----------------------------")
        temperature = dhtDevice.temperature
        humidity = dhtDevice.humidity
        print("Temp: {:.1f}C  Humidity: {}% ".format(temperature, humidity))

        rc,_=mqtt_client.publish("pluto/dht22/temperature", temperature)
        if rc != 0:
            print("Publish temperature error: {}".format(paho.error_string(rc)))
        
        rc,_=mqtt_client.publish("pluto/dht22/humidity", humidity)
        if rc != 0:
            print("Publish humidity error: {}".format(paho.error_string(rc)))


    except RuntimeError as error:
        # Errors happen fairly often, DHT's are hard to read, just keep going
        print(error.args[0])
        time.sleep(2.0)
        continue
    except Exception as error:
        dhtDevice.exit()
        mqtt_client.loop_stop()
        raise error

    time.sleep(5.0)