Air Temp from MQTT

[orrious]

How do you configure njsPC to listen to an MQTT topic for Air Temp and specify whether the temperature is in C or F?

[rstrouse]

You can use an MQTT integration and add your own custom bindings. Below assumes that the incoming values are in C and converts them to whatever units you have set on njsPC. It is assuming you have a topic myRoot/temps/airSensor with a floating point value in degrees C. The topic format can be whatever you like and njsPC will translate it to json. So you could post {"temp":89, "units": "F"} if you like. Then you would replace value with value.temp and value.units respectively. The convert.temperature method will normalize the units for you.

{
  "context": {
    "name": "MyMQTTBindings",
    "options": {
      "clientId": "@bind=`mymqtt_njsPC_${webApp.mac().replace(/:/g, '_'}-${webApp.httpPort()}`;"
    },
    "vars": {}
  },
  "subscriptions": [
    {
      "topic": "/myRoot/temps/airSensor",
      "description": "Subscribe to the air temperature",
      "processor": [
        "if(isNaN(parseFloat(value))) return;",
        "let temp = ctx.util.convert.temperature.convertUnits(parseFloat(value),  'C',sys.board.valueMaps.tempUnits.getName(state.temps.units));",
        "sys.board.system.setTempsAsync({ air: temp });"
      ]
    }
  ]
}

[orrious]

Setup -> Controller -> Interfaces -> Add Interface:
Name: inAirTempMQTT, Type: MQTT and uploaded the following binding:

{
  "context": {
    "name": "inAirTempMQTT",
    "options": {
      "clientId": "@bind=`mymqtt_njsPC_${webApp.mac().replace(/:/g, '_'}-${webApp.httpPort()}`;"
    },
    "vars": {}
  },
  "subscriptions": [
    {
      "topic": "homeassistant/sensor/weatherflow2mqtt_ST-00014928/observation/state",
      "description": "Subscribe to the air temperature",
      "processor": [
        "if(isNaN(parseFloat(value.air_temperature))) return;",
        "let temp = ctx.util.convert.temperature.convertUnits(parseFloat(value.air_temperature),  'C',sys.board.valueMaps.tempUnits.getName(state.temps.units));",
        "sys.board.system.setTempsAsync({ air: temp });"
      ]
    }
  ]
}

Sample output of state topic:

{
  "absolute_humidity": 23.62,
  "air_density": 1.16178,
  "air_temperature": 31.3,
  "battery": 2.68,
  "battery_level": 87,
  "battery_mode_description": "All sensors enabled and operating at full performance. Wind sampling interval every 3 seconds",
  "battery_mode": 0,
  "beaufort_description": "Light breeze",
  "beaufort": 2,
  "cloud_base": 741,
  "delta_t": 4.3,
  "dewpoint": 25.6,
  "dewpoint_description": "Miserable",
  "feelslike": 37.7,
  "freezing_level": 6028,
  "illuminance": 7739,
  "lightning_strike_count": 0,
  "lightning_strike_count_1hr": 0,
  "lightning_strike_count_3hr": 1,
  "lightning_strike_count_today": 1,
  "lightning_strike_distance": 24,
  "lightning_strike_energy": 16784726,
  "precipitation_type": "None",
  "rain_duration_today": 0,
  "rain_duration_yesterday": 0,
  "rain_intensity": "None",
  "rain_rate": 0,
  "rain_today": 0,
  "rain_yesterday": 0,
  "relative_humidity": 71.88,
  "sealevel_pressure": 1018.12,
  "solar_radiation": 65,
  "station_pressure": 1015.18,
  "temperature_description": "Hot",
  "uv": 0.77,
  "uv_description": "Low",
  "visibility": 9.3,
  "wbgt": 28,
  "wetbulb": 27,
  "wind_bearing_avg": 88,
  "wind_direction_avg": "E",
  "wind_gust": 3,
  "wind_lull": 0.7,
  "wind_speed_avg": 1.7,
  "solar_elevation": 14,
  "solar_insolation": 131,
  "zambretti_number": 20,
  "zambretti_text": "Rain at times, worse later",
  "pressure_trend": "Falling",
  "pressure_trend_value": -2.68,
  "last_reset_midnight": "2022-08-01T04:00:00+00:00"
}

Only visible with verbose logging:

[02/08/2022, 09:29:39] info: [09:29:39] 10.1.1.125 PUT /app/interface {"options":{"protocol":"mqtt://","host":"10.1.1.60","port":1883,"username":"","password":"","selfSignedCertificate":false,"rootTopic":"pool/@bind=(state.equipment.model).replace(' ','-').replace(' / ','').toLowerCase();","retain":true,"qos":0,"changesOnly":true},"uuid":"4ef998a5-1fe9-4bf2-93ef-9e31430ad07d","isCustom":true,"name":"inAirTempMQTT","type":"mqtt","fileName":"custom/inAirTempMQTT.json","enabled":true}
[02/08/2022, 09:29:39] info: Init mqtt interface: inAirTempMQTT
[02/08/2022, 09:29:39] info: Initializing MQTT client inAirTempMQTT
[02/08/2022, 09:29:39] info: MQTT connected to mqtt://10.1.1.60:1883
[02/08/2022, 09:29:39] verbose: MQTT subscribed to [{"topic":"pool/nixie-shared body/homeassistant/sensor/weatherflow2mqtt_ST-00014928/observation/state","qos":0}]

See the topic is subscribed to? It is being prepended with pool/nixie-shared body/ I also tried a leading / on my topic, but didn't like that either.

I did notice that when I was configuring MQTT and HomeAssistant interfaces, that the topic that was auto generated included a space between nixie-shared body, however the HomeAssistant state_topic didn't include the space, which left it non-functional. When I changed the topic from a variable to the actual topic pool, njsPC kept overriding it and placing the variable back in its place. I had to stop njsPC, edit config.json and restart for it to work.

[orrious]

This is what I used to get everything working. The issue was the MQTT topic it was trying to subscribe to.

config.json

},
      "inAirTempMQTT": {
        "options": {
          "protocol": "mqtt://",
          "host": "10.1.1.60",
          "port": 1883,
          "username": "",
          "password": "",
          "selfSignedCertificate": false,
          "rootTopic": "homeassistant/sensor/weatherflow2mqtt_ST-00014928/observation",
          "retain": true,
          "qos": 0,
          "changesOnly": true
        },
        "uuid": "4ef998a5-1fe9-4bf2-93ef-9e31430ad07d",
        "isCustom": true,
        "name": "inAirTempMQTT",
        "type": "mqtt",
        "fileName": "custom/inAirTempMQTT.json",
        "enabled": true
      }
    }
  },

web/bindings/custom/inAirTempMQTT.json

{
  "context": {
    "name": "inAirTempMQTT",
    "options": {
      "clientId": "@bind=`mymqtt_njsPC_${webApp.mac().replace(/:/g, '_'}-${webApp.httpPort()}`;"
    },
    "vars": {}
  },
  "subscriptions": [
    {
      "topic": "state",
      "description": "Subscribe to the air temperature",
      "processor": [
        "if(isNaN(parseFloat(value.air_temperature))) return;",
        "let temp = ctx.util.convert.temperature.convertUnits(parseFloat(value.air_temperature),  'C',sys.board.valueMaps.tempUnits.getName(state.temps.uni>
        "sys.board.system.setTempsAsync({ air: temp });"
      ]
    }
  ]
}