vinhlin/mqtt-thingsboard

This is a sample code between Raspberry and the DHT22 Sensor

MQTT-ThingsBoard

• This is a sample code between Raspberry and the DHT22 Sensor
• What are we need:
  • Raspberry Pi 3 (or higher).
  • Sensor DHT22.
  • Account ThingsBoard.
• First, I need install Raspberry OS for your PI.
• Setup SSH for this raspberry device.
• Follow connect between Pi and sensor:

Raspberry	Sensor DHT22
5VDC	5 VDC
GND	GND
GPIO 4	Data

• 

---

Install software and read data

• I need SSH in your raspberry. And update:

sudo apt update
sudo apt-get upgrade

Install some tools

• Install Pip:

sudo apt install python3-pip
pip --version

• Install Git:

sudo apt install git
git --version

Install Adafruit_CircuitPython_DHT

pip3 install adafruit-circuitpython-dht
sudo apt-get install libgpiod2
cd
mkdir lab1-mqtt
cd lab1-mqtt
git clone https://github.com/adafruit/Adafruit_CircuitPython_DHT.git
cd Adafruit_CircuitPython_DHT
python3 -m pip install -r requirements.txt

Test Connection:

cd example
nano dht_simpletest.py

• Change content dhtDevice = adafruit_dht.DHT22(board.D18) to dhtDevice = adafruit_dht.DHT22(board.D4)
• 
• Run:

python3 dht_simpletest.py

• 

---

ThingsBoard

THINGSBOARD_HOST = 'demo.thingsboard.io'
THINGSBOARD_HOST = 'thingsboard.cloud'

Send Data to ThingsBoard

cd Adafruit_CircuitPython_DHT
mkdir thingsboard-dht22

• Source:

import os
import time
import sys
import adafruit_dht
import board
import paho.mqtt.client as mqtt
import json

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

THINGSBOARD_HOST = 'demo.thingsboard.io'
ACCESS_TOKEN = 'XXXXXX'

# Data capture and upload interval in seconds. Less interval will eventually hang the DHT22.
INTERVAL=2

sensor_data = {'temperature': 0, 'humidity': 0}

next_reading = time.time() 

client = mqtt.Client()

# Set access token
client.username_pw_set(ACCESS_TOKEN)

# Connect to ThingsBoard using default MQTT port and 60 seconds keepalive interval
client.connect(THINGSBOARD_HOST, 1883, 60)

client.loop_start()

try:
    while True:

        temperature = dhtDevice.temperature
        humidity = dhtDevice.humidity

        print(
            "Temp: {:.1f} C    Humidity: {}% ".format(
                temperature, humidity
            )
        )
        sensor_data['temperature'] = temperature
        sensor_data['humidity'] = humidity

        # Sending humidity and temperature data to ThingsBoard
        client.publish('v1/devices/me/telemetry', json.dumps(sensor_data), 1)

        next_reading += INTERVAL
        sleep_time = next_reading-time.time()
        if sleep_time > 0:
            time.sleep(sleep_time)
except KeyboardInterrupt:
    pass

client.loop_stop()
client.disconnect()