nodemcu
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Table of Contents
NodeMCU
Introduction
- Website: http://www.nodemcu.com/index_en.html
Summary
- 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.
Dependencies
- Build on ESP8266 sdk 0.9.5
- Lua core based on eLua project
- cjson based on lua-cjson
- File system based on spiffs
Flash the firmware
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
Connect the hardware in serial
baudrate:9600
Start play
Connect to your ap
<source lang=“lua”
>
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
</source>
=
Manipulate hardware like a arduino
<source lang=“lua”
>
pin = 1 gpio.mode(pin,gpio.OUTPUT) gpio.write(pin,gpio.HIGH) print(gpio.read(pin))
</source>
=
Write network application in nodejs style
<source lang=“lua”
>
- -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")
</source>
=
Or a simple http server
<source lang=“lua”
>
- -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)
</source>
=
Connect to MQTT Broker
<source lang=“lua”
>
- -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
</source>
=
UDP client and server
-- 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")