main.lua

ds18b20 = require("ds18b20")

broker = "mqtt"          -- IP or hostname of MQTT broker
mqttport = 1883          -- MQTT port (default 1883)
userID = ""              -- username for authentication if required
userPWD  = ""            -- user password if needed for security
GPIO2 = 4                -- IO Index of GPIO2 which is connected to an LED
count = 0                -- Test number of mqtt_do cycles
mqtt_state = 0           -- State control

clientID = ""

ds18b20.setup(GPIO2)
addrs=ds18b20.addrs()
print("available ds18b20 addresses: "..#addrs)
temp=ds18b20.read(addrs[1], ds18b20.F)
print("current reading of first address: "..temp)

function ds18b20_scan()
    ds18b20 = require("ds18b20")
    ds18b20.setup(GPIO2)
    addrs=ds18b20.addrs()
    temp=ds18b20.read(addrs[1], ds18b20.F)
    ds18b20 = nil
    package.loaded["ds18b20"]=nil
    return temp
end

function mqtt_do()
     count = count + 1  -- For testing number of interations before failure
     
     if mqtt_state < 5 then
          mqtt_state = wifi.sta.status() --State: Waiting for wifi
          print(".")
          local i = 1
          local smac = ""
          for w in string.gmatch(wifi.sta.getmac(), "[^-]+") do
              if i > 4 then smac = smac..w end
              i = i + 1
          end
          clientID = "ESP"..smac

     elseif mqtt_state == 5 then
          m = mqtt.Client(clientID, 120, userID, userPWD)
          m:on("message", 
          function(conn, topic, data)
              print(topic .. ":" )
              if data ~= nil then
                  print(data)
              end
			  -- general reset
			  if topic == "/reset" then
			      node.restart()
			  end
			  -- node specific reset
              if topic == "/reset/"..clientID then
                  node.restart()
              end
          end)
          m:connect( broker , mqttport, 0,
          function(conn)
               print("Connected to MQTT:" .. broker .. ":" .. mqttport .." as " .. clientID )
               m:subscribe("/reset",0,
			   function(conn)
                   print("general reset subscribe success") 
                   m:subscribe("/reset/"..clientID,0,
                   function(conn)
                       print("node reset subscribe success") 
					   m:publish("/node", '{ "node": "'..clientID..'", "features": ["reset", "temperature"] }', 0, 0,
					   function(conn)
				           print("published clientID and features to /node")
					   end)
                   end)
			   end)
               mqtt_state = 20 -- Go to publish state              
          end)

     elseif mqtt_state == 20 then
          mqtt_state = 25 -- Publishing...
          temp = ds18b20_scan()
          m:publish("/temperature/"..clientID,temp, 0, 0,
          function(conn)
              -- Print confirmation of data published
              print("Sent message #"..count.."\nTemp:"..temp.."\npublished!")
              mqtt_state = 25  -- Finished publishing - go back to publish state.
          end)
     else
          --print("Waiting..."..mqtt_state)
          mqtt_state = mqtt_state - 1  -- takes us gradually back to publish state to retry
     end

end

-- release module
ds18b20 = nil
package.loaded["ds18b20"]=nil

tmr.alarm(0, 10000, 1, function() mqtt_do() end)