Thingsboard Telemetry MQTT for Wemos D1 Mini

telemetry.lua

-- send temperature telemetry (Thingsboard.io)

-- require module DS18B20 for temp
local DS18B20 = require "ds18b20"
-- ESP8266 pin
local TEMP_PIN = 2
-- setup DS18B20
DS18B20.setup(TEMP_PIN)
-- flag connected
local connected = false
--MQTT params
local mqtt_settings = {
  module = "ESP8266_"..node.chipid(),
  ip = "host",
  port = 1883,
  token = "<device token>"
}
-- loop to send telemetry
local function send_telemetry()
    if connected == true then
        tmr.alarm(2, 10000, tmr.ALARM_AUTO, function()
            temp = DS18B20.read(nil, 'C')
            --print("Actual temp: "..temp)
            m:publish("v1/devices/me/telemetry", string.format("{\"temperature\":%d}", math.floor(temp)), 0, 0)
        end)
    end
end
-- client mqtt
m = mqtt.Client(mqtt_settings.module, 41, mqtt_settings.token, "password")
-- handler error, try to reconnect
function handler_mqtt_error(client, reason)
  print("Connection fail reason: "..reason)
  connected = false
  tmr.create():alarm(10 * 1000, tmr.ALARM_SINGLE, do_mqtt_connect)
end
-- handler connected
function handler_mqtt_connect(client)
    print("MQTT Connected!")
    connected = true
    send_telemetry()
end
-- try connect broker
function do_mqtt_connect()
  print("Connecting "..node.chipid().." to MQTT broker...")
  m:connect(mqtt_settings.ip, mqtt_settings.port, handler_mqtt_connect, handler_mqtt_error)
end
-- call connect
do_mqtt_connect()