Serial to Mqtt

Simple python script to handle JSON data coming from serial port, ie Arduino node, and forwarding to a MQTT broker.

Connectig to MQTT broker: localhost:1883
Published: {"lux": 300, "temp": 24.23, "press": 1021.2} Topic: iot/6001/o
Published: {"lux": 307, "temp": 24.22, "press": 1021.12} Topic: iot/6001/o
Published: {"lux": 299, "temp": 24.23, "press": 1021.21} Topic: iot/6001/o

Serial port and MQTT broker configuration is done by editing config.json file.

Config.json structure:

{
    "Broker": {
        "Host": "localhost",
        "Port": 1883,
        "ClientID": "clientID",
        "Topic" : ""
        "TopicPrefix": "prefix",
        "TopicSuffix": "suffix",
        "Qos": 0,
        "Cleansess": false
    },
    "Serial": {
        "Port": "/dev/ttyACM1",
        "Baudrate": 9600
    }
}

Serial data format and MQTT Topic selection

The handler expect to read standard JSON data from the serial port:

{'lux': 305, 'temp': 24.17, 'press': 1021.24, 'id': 6001}

MQTT Topic can be specified in the config.json file. It is possible to add prefixes and suffixes, prefix/topic/suffix. For example: iot/MySensorId/out

If Topic is not specified in the configuration file, the handler will look for a JSON field id and used its value.

{'lux': 305, 'temp': 24.17, 'press': 1021.24, 'id': 6001}
Topic: 6001

Launching the script

By default ./config.json is used.

python serialToMqtt.py

Otherwise config file can be specified:

python serialToMqtt.py my_config_file.json

Requirements:

json
pprint
serial
paho.mqtt.client