ip = wifi.sta.getip()
    print(ip)
    --nil
    wifi.setmode(wifi.STATION)
    wifi.sta.config("SSID","password")
    ip = wifi.sta.getip()
    print(ip)
    --192.168.18.110

    pin = 1
    gpio.mode(pin,gpio.OUTPUT)
    gpio.write(pin,gpio.HIGH)
    print(gpio.read(pin))

    -- A simple http client
    conn=net.createConnection(net.TCP, 0) 
    conn:on("receive", function(conn, payload) print(payload) end )
    conn:connect(80,"115.239.210.27")
    conn:send("GET / HTTP/1.1\r\nHost: www.baidu.com\r\n"
        .."Connection: keep-alive\r\nAccept: */*\r\n\r\n")

    -- A simple http server
    srv=net.createServer(net.TCP) 
    srv:listen(80,function(conn) 
      conn:on("receive",function(conn,payload) 
        print(payload) 
        conn:send("<h1> Hello, NodeMcu.</h1>")
      end) 
      conn:on("sent",function(conn) conn:close() end)
    end)

-- init mqtt client with keepalive timer 120sec
m = mqtt.Client("clientid", 120, "user", "password")

-- setup Last Will and Testament (optional)
-- Broker will publish a message with qos = 0, retain = 0, data = "offline" 
-- to topic "/lwt" if client don't send keepalive packet
m:lwt("/lwt", "offline", 0, 0)

m:on("connect", function(con) print ("connected") end)
m:on("offline", function(con) print ("offline") end)

-- on publish message receive event
m:on("message", function(conn, topic, data) 
  print(topic .. ":" ) 
  if data ~= nil then
    print(data)
  end
end)

-- for secure: m:connect("192.168.11.118", 1880, 1)
m:connect("192.168.11.118", 1880, 0, function(conn) print("connected") end)

-- subscribe topic with qos = 0
m:subscribe("/topic",0, function(conn) print("subscribe success") end)
-- or subscribe multiple topic (topic/0, qos = 0; topic/1, qos = 1; topic2 , qos = 2)
-- m:subscribe({["topic/0"]=0,["topic/1"]=1,topic2=2}, function(conn) print("subscribe success") end)
-- publish a message with data = hello, QoS = 0, retain = 0
m:publish("/topic","hello",0,0, function(conn) print("sent") end)

m:close();
-- you can call m:connect again

-- a udp server
s=net.createServer(net.UDP) 
s:on("receive",function(s,c) print(c) end)
s:listen(5683)

-- a udp client
cu=net.createConnection(net.UDP) 
cu:on("receive",function(cu,c) print(c) end) 
cu:connect(5683,"192.168.18.101") 
cu:send("hello")

  function led(r,g,b) 
    pwm.setduty(1,r) 
    pwm.setduty(2,g) 
    pwm.setduty(3,b) 
  end
  pwm.setup(1,500,512) 
  pwm.setup(2,500,512) 
  pwm.setup(3,500,512)
  pwm.start(1) 
  pwm.start(2) 
  pwm.start(3)
  led(512,0,0) -- red
  led(0,0,512) -- blue

  lighton=0
  tmr.alarm(1,1000,1,function()
    if lighton==0 then 
      lighton=1 
      led(512,512,512) 
    else 
      lighton=0 
      led(0,0,0) 
    end 
  end)

  --init.lua will be excuted
  file.open("init.lua","w")
  file.writeline([[print("Hello, do this at the beginning.")]])
  file.close()
  node.restart()  -- this will restart the module.

    -- a simple telnet server
    s=net.createServer(net.TCP,180) 
    s:listen(2323,function(c) 
       function s_output(str) 
          if(c~=nil) 
             then c:send(str) 
          end 
       end 
       node.output(s_output, 0)   -- re-direct output to function s_ouput.
       c:on("receive",function(c,l) 
          node.input(l)           -- works like pcall(loadstring(l)) but support multiple separate line
       end) 
       c:on("disconnection",function(c) 
          node.output(nil)        -- un-regist the redirect output function, output goes to serial
       end) 
       print("Welcome to NodeMcu world.")
    end)

    -- read temperature with DS18B20
    t=require("ds18b20")
    t.setup(9)
    addrs=t.addrs()
    -- Total DS18B20 numbers, assume it is 2
    print(table.getn(addrs))
    -- The first DS18B20
    print(t.read(addrs[1],t.C))
    print(t.read(addrs[1],t.F))
    print(t.read(addrs[1],t.K))
    -- The second DS18B20
    print(t.read(addrs[2],t.C))
    print(t.read(addrs[2],t.F))
    print(t.read(addrs[2],t.K))
    -- Just read
    print(t.read())
    -- Just read as centigrade
    print(t.read(nil,t.C))
    -- Don't forget to release it after use
    t = nil
	ds18b20 = nil
    package.loaded["ds18b20"]=nil