VOC_CO2_station

CO2 and volatile organic compounds measurement using IoT sensors and Raspberry Pi.

MQTT topics:

• co2
• voc
• co2eq
• temp
• rh

JSON format:

• { ‘device_name’ : (string), ‘co2’ : (float) }
• { ‘device_name’ : (string), ‘co2eq’: (int) }
• { ‘device_name’ : (string), ‘voc’ : (int) }
• { ‘device_name’ : (string), ‘temp’: (float) }
• { ‘device_name’ : (string), ‘rh’ : (float) }

Ranges and units

• VOC: 0 - 60,000 [ppb]
• CO2eq: 400 - 60,000 [ppm]
• TEMP: -20 – 85 (+/- 1) [°C]
• RH: 0 - 100 (+/- 5) [% relative humidity]
• CO2: 0 - 40,000 (+/- 30) [ppm]

Configuration

1. MQTT Broker

Install Mosquitto:

sudo apt-get install mosquitto

Add configuration to the end of /etc/mosquitto/mosquitto.conf file:

listener 1850 0.0.0.0
allow_anonymous true

2. MQTT clients

pip3 install paho-mqtt
PYTHONPATH=$PYTHONPATH:/path/to/project/workdir/.
export PYTHONPATH

Usage

1. Start Mosquitto MQTT Broker:

sudo service mosquitto start

2. Start publishers on Raspberry Pi:

python3 svm30collector.py --host <ip>:1850 --client_id client_pub_1 --topic_base svm30/
python3 scd30collector.py --host <ip>:1850 --client_id client_pub_2 --topic_base scd30/

3. Start subscriber:

python test/testSubscriber.py --host <ip>:1850 --client_id client_sub_1