• FAQ: http://www.esp8266.com/wiki/doku.php?id=nodemcu-unofficial-faq

NodeMCU devkit is a development kit for NodeMCU firmware.
It will make NodeMCU more easy. With a micro USB cable, you can connect NodeMCU devkit to your laptop and flash it without any trouble, just like Arduino.
It is an open hardware, with ESP-12 core with 32Mbits(4MBytes) flash.

It is the original design of NodeMCU devkit. Very old and never sell on shop. It can't automatic flash firmware.

It is the second design of NodeMCU devkit. It uses CH340G as UART bridge, and can flash firmware automatically by using nodemcu-flasher.

It is the 5th design of NodeMCU devkit. It uses CP2102 as UART bridge, and can flash firmware automatically by using nodemcu-flasher. It support apple's MAC OS.

• Website: http://www.nodemcu.com/index_en.html
• Forum: http://www.esp8266.com/viewforum.php?f=17
• Firmware: https://github.com/nodemcu/nodemcu-firmware
• Hardware: https://github.com/nodemcu/nodemcu-devkit
• Flasher: https://github.com/nodemcu/nodemcu-flasher

• Easy to access wireless router
• Based on Lua 5.1.4 (without debug, os module.)
• Event-Drive programming preferred.
• Build-in json, file, timer, pwm, i2c, spi, 1-wire, net, mqtt, coap, gpio, wifi, adc, uart and system api.
• GPIO pin re-mapped, use the index to access gpio, i2c, pwm.
• Both Integer(less memory usage) and Float version firmware provided.

• Build on ESP8266 sdk 0.9.5
• Lua core based on eLua project
• cjson based on lua-cjson
• File system based on spiffs

nodemcu_latest.bin: 0x00000
for most esp8266 modules, just pull GPIO0 down and restart.
You can use the nodemcu-flasher to burn the firmware.

Or, if you build your own bin from source code.
0x00000.bin: 0x00000
0x10000.bin: 0x10000

Better run file.format() after flash

baudrate:9600

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")