MQTT_BRIDGE

A simple package that allows you to create a bridge between mqtt and a serial port

INSTALLATION

npm install -g @adamfraczkowski/mqtt_bridge

HOW TO USE

1. Create config json file. allowed parameters:

• mqttConnectionString - mqtt connection string ex: "mqtt://test.mosquitto.org", follow MQTT.js to determine correct connection string
• mode - "serial","terminal" or "gpio",
• baud - baudrate for serial device,
• port - serial port id,
• dataFormat - "hexstring" or "raw". In "hexstring" dataformat Buffer bytes from serial are converted to hexstring. Hex string values published to mqtt are converted to buffer,
• inputTopic - topic for publishing data TO device,
• outputTopic - Topic where you can receive data from device
• commandTopic - Topic where you can send custom command to mqtt bridge.
• shell - In terminal mode - terminal shell - for example "cmd.exe", "bash", "powershell.exe"
• gpioConfig - In gpio mode - JSON object that determine gpio configs - see config_gpio.json

2. execute command:

mqtt_bridge config <path to your config json file>

COMMAND LIST

• terminate - command that terminates mqtt bridge. When your device not working well you can try to restart mqtt_bridge executing that command. After that your process manager like PM2 can restart your mqtt_bridge process

GPIO mode

bridge uses WiringPI as backend. It uses GPIO tool utility. It should be available in the system as gpio command. Example:

 gpio readall 

For banana pi use this version:

https://github.com/bontango/BPI-WiringPi2

GPIO inputs:

Emitted objects (JSON):

    {
        "pin":<pin from wiringPI>,
        "dir":<"in"/"out">,
        "timestamp":<timestamp in millis>,
        "value":<true/false>,
        "event":<"press"/"longpress">
    }

Objects to send:

    {
        "cmd":<"setpin"/"blinkpin"/"start"/"stop">,
        "data":{
            "pin":<pin from wiringPI>,
            "value":<true/false>,
            "onTime":<on time in milliseconds - for blink>,
            "offTime":<off time in milliseconds - for blink>,
            "times":<number of blinks - for blink>
        }
    }

Example config file:

serial mode:

{
   "mqttConnectionString":"mqtt://test.mosquitto.org",
   "mode":"serial",
   "baud":57600,
   "port":"COM2",
   "dataFormat":"hexstring",
   "inputTopic":"serial-device/input",
   "outputTopic":"serial-device/output"
}

terminal mode:

{
   "mqttConnectionString":"mqtt://broker.hivemq.com:1883",
   "mode":"terminal",
   "shell":"cmd.exe",
   "inputTopic":"terminal-bridge/input",
   "outputTopic":"terminal-bridge/output",
   "commandTopic":"mqtt-bridge/command"
}

gpio mode:

{
   "mqttConnectionString":"mqtt://broker.hivemq.com:1883",
   "mode":"gpio",
   "gpioConfig":[
       {"pin":15,"dir":"in","pull":"down"},
       {"pin":16,"dir":"in","pull":"down"},
       {"pin":7,"dir":"out","pull":"down"},
       {"pin":8,"dir":"out","pull":"down"},
       {"pin":9,"dir":"out","pull":"down"}
   ],
   "inputTopic":"gpio-bridge/input",
   "outputTopic":"gpio-bridge/output",
   "commandTopic":"gpio-bridge/command"
}