diff --git a/lua_modules/si7021/si7021-example.lua b/lua_modules/si7021/si7021-example.lua
new file mode 100644
index 00000000..5c6ed6cc
--- /dev/null
+++ b/lua_modules/si7021/si7021-example.lua
@@ -0,0 +1,24 @@
+
+tmr.alarm(0, 60000, 1, function()
+
+	SDA_PIN = 6 -- sda pin, GPIO12
+	SCL_PIN = 5 -- scl pin, GPIO14
+
+	si7021 = require("si7021")
+	si7021.init(SDA_PIN, SCL_PIN)
+	si7021.read(OSS)
+	h = si7021.getHumidity()
+	t = si7021.getTemperature()
+
+	-- pressure in differents units
+	print("Humidity: "..(h / 100).."."..(h % 100).." %")
+
+	-- temperature in degrees Celsius  and Farenheit
+	print("Temperature: "..(t/100).."."..(t%100).." deg C")
+	print("Temperature: "..(9 * t / 500 + 32).."."..(9 * t / 50 % 10).." deg F")
+
+	-- release module
+	si7021 = nil
+	package.loaded["si7021"]=nil
+
+end)
diff --git a/lua_modules/si7021/si7021-lewei.lua b/lua_modules/si7021/si7021-lewei.lua
new file mode 100644
index 00000000..28ac9189
--- /dev/null
+++ b/lua_modules/si7021/si7021-lewei.lua
@@ -0,0 +1,41 @@
+
+    --创建一个定时器
+    tmr.alarm(0, 60000, 1, function()
+
+		SDA_PIN = 6 -- sda pin, GPIO12
+		SCL_PIN = 5 -- scl pin, GPIO14
+
+		si7021 = require("si7021")
+		si7021.init(SDA_PIN, SCL_PIN)
+		si7021.read(OSS)
+		Hum = si7021.getHumidity()
+		Temp = si7021.getTemperature()
+
+    	--定义数据变量格式
+    	PostData = "[{\"Name\":\"T\",\"Value\":\"" .. (Temp/100).."."..(Temp%100) .. "\"},{\"Name\":\"H\",\"Value\":\"" .. (Hum/100).."."..(Hum%100) .. "\"}]"
+    	--创建一个TCP连接
+    	socket=net.createConnection(net.TCP, 0)
+    	--域名解析IP地址并赋值
+    	socket:dns("www.lewei50.com", function(conn, ip)
+    		ServerIP = ip
+    		print("Connection IP:" .. ServerIP)
+    		end)
+    	--开始连接服务器
+    	socket:connect(80, ServerIP)
+    	socket:on("connection", function(sck) end)
+    	--HTTP请求头定义
+    	socket:send("POST /api/V1/gateway/UpdateSensors/yourID HTTP/1.1\r\n" ..
+    				"Host: www.lewei50.com\r\n" ..
+    				"Content-Length: " .. string.len(PostData) .. "\r\n" ..
+    				"userkey: yourKEY\r\n\r\n" ..
+    				PostData .. "\r\n")
+    	--HTTP响应内容
+    	socket:on("receive", function(sck, response)
+    		print(response)
+    		end)
+
+		-- release module
+		si7021 = nil
+		package.loaded["si7021"]=nil
+
+	    end)
diff --git a/lua_modules/si7021/si7021.EN.md b/lua_modules/si7021/si7021.EN.md
new file mode 100644
index 00000000..983bb978
--- /dev/null
+++ b/lua_modules/si7021/si7021.EN.md
@@ -0,0 +1,131 @@
+# si7021 module
+
+##Require
+```lua
+si7021 = require("si7021")
+```
+## Release
+```lua
+si7021 = nil
+package.loaded["si7021"]=nil
+```
+<a id="si7021_init"></a>
+##init()
+####Description
+Setting the i2c pin of si7021.<br />
+
+####Syntax
+init(sda, scl)
+
+####Parameters
+sda: 1~12, IO index.<br />
+scl: 1~12, IO index.<br />
+
+####Returns
+nil
+
+####Example
+```lua
+si7021 = require("si7021")
+gpio5 = 1
+gpio4 = 2
+sda = gpio5
+scl = gpio4
+si7021.init(sda, scl)
+-- Don't forget to release it after use
+si7021 = nil
+package.loaded["si7021"]=nil
+```
+
+####See also
+**-**   []()
+
+<a id="si7021_read"></a>
+##read()
+####Description
+Read temperature and humidity from si7021.<br />
+
+####Syntax
+read()
+
+####Parameters
+nil.<br />
+
+####Returns
+nil(Why?).<br />
+
+####Example
+```lua
+si7021 = require("si7021")
+sda = 1
+scl = 2
+si7021.init(sda, scl)
+r = si7021.read()
+print(r)
+-- Don't forget to release it after use
+si7021 = nil
+package.loaded["si7021"]=nil
+```
+
+####See also
+**-**   []()
+
+<a id="si7021_getHumidity"></a>
+##getHumidity()
+####Description
+Get humidity from si7021.<br />
+
+####Syntax
+getHumidity()
+
+####Parameters
+nil.<br />
+
+####Returns
+h: Integer, humidity from si7021.
+
+####Example
+```lua
+si7021 = require("si7021")
+sda = 1
+scl = 2
+si7021.init(sda, scl)
+h = si7021.getHumidity()
+print(h)
+-- Don't forget to release it after use
+si7021 = nil
+package.loaded["si7021"]=nil
+```
+
+####See also
+**-**   []()
+
+<a id="si7021_getTemperature"></a>
+##getTemperature()
+####Description
+Get temperature from si7021.<br />
+
+####Syntax
+getTemperature()
+
+####Parameters
+nil.<br />
+
+####Returns
+t: Integer, temperature from si7021.
+
+####Example
+```lua
+si7021 = require("si7021")
+sda = 1
+scl = 2
+si7021.init(sda, scl)
+t = si7021.getTemperature()
+print(t)
+-- Don't forget to release it after use
+si7021 = nil
+package.loaded["si7021"]=nil
+```
+
+####See also
+**-**   []()
diff --git a/lua_modules/si7021/si7021.lua b/lua_modules/si7021/si7021.lua
new file mode 100644
index 00000000..161e57d2
--- /dev/null
+++ b/lua_modules/si7021/si7021.lua
@@ -0,0 +1,104 @@
+-- ***************************************************************************
+-- SI7021 module for ESP8266 with nodeMCU
+-- Si7021 compatible tested 2015-1-22
+--
+-- Written by VIP6
+--
+-- MIT license, http://opensource.org/licenses/MIT
+-- ***************************************************************************
+
+local moduleName = ...
+local M = {}
+_G[moduleName] = M
+
+--I2C slave address of Si70xx
+local Si7021_ADDR = 0x40
+
+--Commands
+local CMD_MEASURE_HUMIDITY_HOLD = 0xE5
+local CMD_MEASURE_HUMIDITY_NO_HOLD = 0xF5
+local CMD_MEASURE_TEMPERATURE_HOLD = 0xE3
+local CMD_MEASURE_TEMPERATURE_NO_HOLD = 0xF3
+
+
+-- temperature and pressure
+local t,h
+
+local init = false
+
+-- i2c interface ID
+local id = 0
+
+-- 16-bit  two's complement
+-- value: 16-bit integer
+local function twoCompl(value)
+ if value > 32767 then value = -(65535 - value + 1)
+ end
+ return value
+end
+
+
+
+-- read data from si7021
+-- ADDR: slave address
+-- commands: Commands of si7021
+-- length: bytes to read
+local function read_data(ADDR, commands, length)
+  i2c.start(id)
+  i2c.address(id, ADDR, i2c.TRANSMITTER)
+  i2c.write(id, commands)
+  i2c.stop(id)
+  i2c.start(id)
+  i2c.address(id, ADDR,i2c.RECEIVER)
+  tmr.delay(20000)
+  c = i2c.read(id, length)
+  i2c.stop(id)
+  return c
+end
+
+-- initialize module
+-- sda: SDA pin
+-- scl SCL pin
+function M.init(sda, scl)
+  i2c.setup(id, sda, scl, i2c.SLOW)
+  --print("i2c ok..")
+  init = true
+end
+
+-- read humidity from si7021
+local function read_humi()
+  dataH = read_data(Si7021_ADDR, CMD_MEASURE_HUMIDITY_HOLD, 2)
+  UH = string.byte(dataH, 1) * 256 + string.byte(dataH, 2)
+  h = ((UH*12500+65536/2)/65536 - 600)
+  return(h)
+end
+
+-- read temperature from si7021
+local function read_temp()
+  dataT = read_data(Si7021_ADDR, CMD_MEASURE_TEMPERATURE_HOLD, 2)
+  UT = string.byte(dataT, 1) * 256 + string.byte(dataT, 2)
+  t = ((UT*17572+65536/2)/65536 - 4685)
+  return(t)
+end
+
+-- read temperature and humidity from si7021
+function M.read()
+  if (not init) then
+     print("init() must be called before read.")
+  else
+	 read_humi()
+	 read_temp()
+  end
+end;
+
+-- get humidity
+function M.getHumidity()
+  return h
+end
+
+-- get temperature
+function M.getTemperature()
+  return t
+end
+
+return M