diff --git a/Makefile b/Makefile
index 85bc27a9..19feb38d 100644
--- a/Makefile
+++ b/Makefile
@@ -103,9 +103,15 @@ OIMAGES := $(GEN_IMAGES:%=$(IMAGEODIR)/%)
 BINODIR := $(ODIR)/$(TARGET)/$(FLAVOR)/bin
 OBINS := $(GEN_BINS:%=$(BINODIR)/%)
 
+#
+# Note: 
+# https://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html
+# If you add global optimize options like "-O2" here 
+# they will override "-Os" defined above.
+# "-Os" should be used to reduce code size
+#
 CCFLAGS += 			\
 	-g			\
-	-O2			\
 	-Wpointer-arith		\
 	-Wundef			\
 	-Werror			\
diff --git a/README.md b/README.md
index 75bdcc7f..295ea337 100644
--- a/README.md
+++ b/README.md
@@ -426,6 +426,7 @@ In contrast to the source code based inclusion of XBMs into u8glib, it's require
   - [ ] setPrintPos()
   - [ ] setHardwareBackup()
   - [ ] setRGB()
+  - [ ] setDefaultMidColor()
 
 
 ####Control a WS2812 based light strip
diff --git a/app/modules/net.c b/app/modules/net.c
index dbd072f1..bb36d45b 100644
--- a/app/modules/net.c
+++ b/app/modules/net.c
@@ -204,13 +204,12 @@ static void net_dns_found(const char *name, ip_addr_t *ipaddr, void *arg)
     NODE_DBG("self_ref null.\n");
     return;
   }
-
+/* original
   if(ipaddr == NULL)
   {
     NODE_ERR( "DNS Fail!\n" );
     goto end;
   }
-
   // ipaddr->addr is a uint32_t ip
   char ip_str[20];
   c_memset(ip_str, 0, sizeof(ip_str));
@@ -220,9 +219,30 @@ static void net_dns_found(const char *name, ip_addr_t *ipaddr, void *arg)
   }
 
   lua_rawgeti(gL, LUA_REGISTRYINDEX, nud->cb_dns_found_ref);    // the callback function
-  lua_rawgeti(gL, LUA_REGISTRYINDEX, nud->self_ref);  // pass the userdata(conn) to callback func in lua
+  //lua_rawgeti(gL, LUA_REGISTRYINDEX, nud->self_ref);  // pass the userdata(conn) to callback func in lua
   lua_pushstring(gL, ip_str);   // the ip para
-  lua_call(gL, 2, 0);
+*/
+
+  // "enhanced"
+  lua_rawgeti(gL, LUA_REGISTRYINDEX, nud->cb_dns_found_ref);    // the callback function
+
+  if(ipaddr == NULL)
+  {
+    NODE_DBG( "DNS Fail!\n" );
+    lua_pushnil(gL);
+  }else{
+    // ipaddr->addr is a uint32_t ip
+    char ip_str[20];
+    c_memset(ip_str, 0, sizeof(ip_str));
+    if(host_ip.addr == 0 && ipaddr->addr != 0)
+    {
+      c_sprintf(ip_str, IPSTR, IP2STR(&(ipaddr->addr)));
+    }
+    lua_pushstring(gL, ip_str);   // the ip para
+  }
+  // "enhanced" end
+
+  lua_call(gL, 1, 0);
 
 end:
   if((pesp_conn->type == ESPCONN_TCP && pesp_conn->proto.tcp->remote_port == 0)
@@ -1119,6 +1139,71 @@ static int net_dns( lua_State* L, const char* mt )
   return 0;  
 }
 
+// Lua: net.dns.resolve( domain, function(ip) )
+static int net_dns_static( lua_State* L )
+{
+  const char *mt = "net.socket";
+  if (!lua_isstring( L, 1 ))
+    return luaL_error( L, "wrong parameter type (domain)" );
+  
+  int rfunc = LUA_NOREF; //save reference to func
+  if (lua_type(L, 2) == LUA_TFUNCTION || lua_type(L, 2) == LUA_TLIGHTFUNCTION){
+    rfunc = luaL_ref(L, LUA_REGISTRYINDEX);
+  }
+  int rdom = luaL_ref(L, LUA_REGISTRYINDEX); //save reference to domain
+
+  lua_settop(L,0); //empty stack
+  lua_getfield(L, LUA_GLOBALSINDEX, "net");
+  lua_getfield(L, -1, "createConnection");
+  lua_remove(L, -2); //remove "net" from stack
+  lua_pushinteger(L, UDP); // we are going to create a new dummy UDP socket
+  lua_call(L,1,1);// after this the stack should have a socket
+
+  lua_rawgeti(gL, LUA_REGISTRYINDEX, rdom);    // load domain back to the stack
+  lua_rawgeti(gL, LUA_REGISTRYINDEX, rfunc);    // load the callback function back to the stack
+
+  luaL_unref(L, LUA_REGISTRYINDEX, rdom); //free reference
+  luaL_unref(L, LUA_REGISTRYINDEX, rfunc); //free reference
+
+  bool isserver = false;
+  struct espconn *pesp_conn = NULL;
+  lnet_userdata *nud;
+  size_t l;
+  
+  nud = (lnet_userdata *)luaL_checkudata(L, 1, mt);
+  luaL_argcheck(L, nud, 1, "Server/Socket expected");
+  if(nud==NULL){
+    NODE_DBG("userdata is nil.\n");
+    return 0;
+  }
+  if(nud->pesp_conn == NULL){
+    NODE_DBG("nud->pesp_conn is NULL.\n");
+    return 0;
+  }
+  pesp_conn = nud->pesp_conn;
+
+  lua_pushvalue(L, 1);  // copy to the top of stack
+  if(nud->self_ref != LUA_NOREF)
+    luaL_unref(L, LUA_REGISTRYINDEX, nud->self_ref);
+  nud->self_ref = luaL_ref(L, LUA_REGISTRYINDEX);
+
+  const char *domain = luaL_checklstring( L, 2, &l );
+  if (l>128 || domain == NULL)
+    return luaL_error( L, "need <128 domain" );
+
+  if (lua_type(L, 3) == LUA_TFUNCTION || lua_type(L, 3) == LUA_TLIGHTFUNCTION){
+    lua_pushvalue(L, 3);  // copy argument (func) to the top of stack
+    if(nud->cb_dns_found_ref != LUA_NOREF)
+      luaL_unref(L, LUA_REGISTRYINDEX, nud->cb_dns_found_ref);
+    nud->cb_dns_found_ref = luaL_ref(L, LUA_REGISTRYINDEX);
+  }
+
+  host_ip.addr = 0;
+  espconn_gethostbyname(pesp_conn, domain, &host_ip, net_dns_found);
+
+  return 0;
+}
+
 // Lua: s = net.createServer(type, function(server))
 static int net_createServer( lua_State* L )
 {
@@ -1332,6 +1417,48 @@ static int net_multicastLeave( lua_State* L )
 }
 
 
+// Lua: s = net.dns.setdnsserver(ip_addr, [index])
+static int net_setdnsserver( lua_State* L )
+{
+  size_t l;
+  u32_t ip32;
+
+  const char *server = luaL_checklstring( L, 1, &l );
+  if (l>16 || server == NULL || (ip32 = ipaddr_addr(server)) == IPADDR_NONE || ip32 == IPADDR_ANY)
+    return luaL_error( L, "invalid dns server ip" );
+
+  int numdns = luaL_optint(L, 2, 0);
+  if (numdns >= DNS_MAX_SERVERS)
+    return luaL_error( L, "server index out of range [0-%d]", DNS_MAX_SERVERS - 1);
+
+  ip_addr_t ipaddr;
+  ip4_addr_set_u32(&ipaddr, ip32);
+  dns_setserver(numdns,&ipaddr);
+
+  return 0;
+}
+
+// Lua: s = net.dns.getdnsserver([index])
+static int net_getdnsserver( lua_State* L )
+{
+  int numdns = luaL_optint(L, 1, 0);
+  if (numdns >= DNS_MAX_SERVERS)
+    return luaL_error( L, "server index out of range [0-%d]", DNS_MAX_SERVERS - 1);
+
+  ip_addr_t ipaddr;
+  dns_getserver(numdns,&ipaddr);
+
+  if ( ip_addr_isany(&ipaddr) ) {
+    lua_pushnil( L );
+  } else {
+    char temp[20] = {0};
+    c_sprintf(temp, IPSTR, IP2STR( &ipaddr ) );
+    lua_pushstring( L, temp );
+  }
+
+  return 1;
+}
+
 #if 0
 static int net_array_index( lua_State* L )
 {
@@ -1402,6 +1529,15 @@ static const LUA_REG_TYPE net_array_map[] =
   { LNILKEY, LNILVAL }
 };
 #endif
+
+static const LUA_REG_TYPE net_dns_map[] =
+{
+  { LSTRKEY( "setdnsserver" ), LFUNCVAL ( net_setdnsserver ) },  
+  { LSTRKEY( "getdnsserver" ), LFUNCVAL ( net_getdnsserver ) }, 
+  { LSTRKEY( "resolve" ), LFUNCVAL ( net_dns_static ) },  
+  { LNILKEY, LNILVAL }
+};
+
 const LUA_REG_TYPE net_map[] = 
 {
   { LSTRKEY( "createServer" ), LFUNCVAL ( net_createServer ) },
@@ -1409,6 +1545,7 @@ const LUA_REG_TYPE net_map[] =
   { LSTRKEY( "multicastJoin"), LFUNCVAL( net_multicastJoin ) },
   { LSTRKEY( "multicastLeave"), LFUNCVAL( net_multicastLeave ) },
 #if LUA_OPTIMIZE_MEMORY > 0
+  { LSTRKEY( "dns" ), LROVAL( net_dns_map ) },
   { LSTRKEY( "TCP" ), LNUMVAL( TCP ) },
   { LSTRKEY( "UDP" ), LNUMVAL( UDP ) },
 
@@ -1471,6 +1608,12 @@ LUALIB_API int luaopen_net( lua_State *L )
   // Setup the methods inside metatable
   luaL_register( L, NULL, net_array_map );
 #endif
+
+  lua_settop(L, n);
+  lua_newtable( L );
+  luaL_register( L, NULL, net_dns_map );
+  lua_setfield( L, -2, "dns" );
+
   return 1;
 #endif // #if LUA_OPTIMIZE_MEMORY > 0  
 }
diff --git a/app/modules/u8g.c b/app/modules/u8g.c
index fc39803b..3596ab06 100644
--- a/app/modules/u8g.c
+++ b/app/modules/u8g.c
@@ -760,6 +760,39 @@ static int lu8g_getHeight( lua_State *L )
     return 1;
 }
 
+// Lua: width = u8g.getStrWidth( self, string )
+static int lu8g_getStrWidth( lua_State *L )
+{
+   lu8g_userdata_t *lud;
+
+    if ((lud = get_lud( L )) == NULL)
+        return 0;
+
+    const char *s = luaL_checkstring( L, 2 );
+    if (s == NULL)
+        return 0;
+
+    lua_pushinteger( L, u8g_GetStrWidth( LU8G, s ) );
+
+    return 1;
+}
+
+// Lua: u8g.setFontLineSpacingFactor( self, factor )
+static int lu8g_setFontLineSpacingFactor( lua_State *L )
+{
+   lu8g_userdata_t *lud;
+
+    if ((lud = get_lud( L )) == NULL)
+        return 0;
+
+    u8g_uint_t factor = luaL_checkinteger( L, 2 );
+
+    u8g_SetFontLineSpacingFactor( LU8G, factor );
+
+    return 0;
+}
+
+
 // ------------------------------------------------------------
 // comm functions
 //
@@ -1140,53 +1173,55 @@ static int lu8g_pcd8544_84x48( lua_State *L )
 static const LUA_REG_TYPE lu8g_display_map[] =
 {
     { LSTRKEY( "begin" ),  LFUNCVAL( lu8g_begin ) },
-    { LSTRKEY( "setFont" ),  LFUNCVAL( lu8g_setFont ) },
-    { LSTRKEY( "setFontRefHeightAll" ),  LFUNCVAL( lu8g_setFontRefHeightAll ) },
-    { LSTRKEY( "setFontRefHeightExtendedText" ),  LFUNCVAL( lu8g_setFontRefHeightExtendedText ) },
-    { LSTRKEY( "setFontRefHeightText" ),  LFUNCVAL( lu8g_setFontRefHeightText ) },
-    { LSTRKEY( "setDefaultBackgroundColor" ),  LFUNCVAL( lu8g_setDefaultBackgroundColor ) },
-    { LSTRKEY( "setDefaultForegroundColor" ),  LFUNCVAL( lu8g_setDefaultForegroundColor ) },
-    { LSTRKEY( "setFontPosBaseline" ),  LFUNCVAL( lu8g_setFontPosBaseline ) },
-    { LSTRKEY( "setFontPosBottom" ),  LFUNCVAL( lu8g_setFontPosBottom ) },
-    { LSTRKEY( "setFontPosCenter" ),  LFUNCVAL( lu8g_setFontPosCenter ) },
-    { LSTRKEY( "setFontPosTop" ),  LFUNCVAL( lu8g_setFontPosTop ) },
-    { LSTRKEY( "getFontAscent" ),  LFUNCVAL( lu8g_getFontAscent ) },
-    { LSTRKEY( "getFontDescent" ),  LFUNCVAL( lu8g_getFontDescent ) },
-    { LSTRKEY( "getFontLineSpacing" ),  LFUNCVAL( lu8g_getFontLineSpacing ) },
-    { LSTRKEY( "getMode" ),  LFUNCVAL( lu8g_getMode ) },
-    { LSTRKEY( "setColorIndex" ),  LFUNCVAL( lu8g_setColorIndex ) },
-    { LSTRKEY( "getColorIndex" ),  LFUNCVAL( lu8g_getColorIndex ) },
+    { LSTRKEY( "drawBitmap" ),  LFUNCVAL( lu8g_drawBitmap ) },
+    { LSTRKEY( "drawBox" ),  LFUNCVAL( lu8g_drawBox ) },
+    { LSTRKEY( "drawCircle" ),  LFUNCVAL( lu8g_drawCircle ) },
+    { LSTRKEY( "drawDisc" ),  LFUNCVAL( lu8g_drawDisc ) },
+    { LSTRKEY( "drawEllipse" ),  LFUNCVAL( lu8g_drawEllipse ) },
+    { LSTRKEY( "drawFilledEllipse" ),  LFUNCVAL( lu8g_drawFilledEllipse ) },
+    { LSTRKEY( "drawFrame" ),  LFUNCVAL( lu8g_drawFrame ) },
+    { LSTRKEY( "drawHLine" ),  LFUNCVAL( lu8g_drawHLine ) },
+    { LSTRKEY( "drawLine" ),  LFUNCVAL( lu8g_drawLine ) },
+    { LSTRKEY( "drawPixel" ),  LFUNCVAL( lu8g_drawPixel ) },
+    { LSTRKEY( "drawRBox" ),  LFUNCVAL( lu8g_drawRBox ) },
+    { LSTRKEY( "drawRFrame" ),  LFUNCVAL( lu8g_drawRFrame ) },
     { LSTRKEY( "drawStr" ),  LFUNCVAL( lu8g_drawStr ) },
     { LSTRKEY( "drawStr90" ),  LFUNCVAL( lu8g_drawStr90 ) },
     { LSTRKEY( "drawStr180" ),  LFUNCVAL( lu8g_drawStr180 ) },
     { LSTRKEY( "drawStr270" ),  LFUNCVAL( lu8g_drawStr270 ) },
-    { LSTRKEY( "drawBox" ),  LFUNCVAL( lu8g_drawBox ) },
-    { LSTRKEY( "drawLine" ),  LFUNCVAL( lu8g_drawLine ) },
     { LSTRKEY( "drawTriangle" ),  LFUNCVAL( lu8g_drawTriangle ) },
-    { LSTRKEY( "drawRBox" ),  LFUNCVAL( lu8g_drawRBox ) },
-    { LSTRKEY( "drawFrame" ),  LFUNCVAL( lu8g_drawFrame ) },
-    { LSTRKEY( "drawRFrame" ),  LFUNCVAL( lu8g_drawRFrame ) },
-    { LSTRKEY( "drawDisc" ),  LFUNCVAL( lu8g_drawDisc ) },
-    { LSTRKEY( "drawCircle" ),  LFUNCVAL( lu8g_drawCircle ) },
-    { LSTRKEY( "drawEllipse" ),  LFUNCVAL( lu8g_drawEllipse ) },
-    { LSTRKEY( "drawFilledEllipse" ),  LFUNCVAL( lu8g_drawFilledEllipse ) },
-    { LSTRKEY( "drawPixel" ),  LFUNCVAL( lu8g_drawPixel ) },
-    { LSTRKEY( "drawHLine" ),  LFUNCVAL( lu8g_drawHLine ) },
     { LSTRKEY( "drawVLine" ),  LFUNCVAL( lu8g_drawVLine ) },
-    { LSTRKEY( "drawBitmap" ),  LFUNCVAL( lu8g_drawBitmap ) },
     { LSTRKEY( "drawXBM" ),  LFUNCVAL( lu8g_drawXBM ) },
-    { LSTRKEY( "setScale2x2" ),  LFUNCVAL( lu8g_setScale2x2 ) },
-    { LSTRKEY( "undoScale" ),  LFUNCVAL( lu8g_undoScale ) },
     { LSTRKEY( "firstPage" ),  LFUNCVAL( lu8g_firstPage ) },
+    { LSTRKEY( "getColorIndex" ),  LFUNCVAL( lu8g_getColorIndex ) },
+    { LSTRKEY( "getFontAscent" ),  LFUNCVAL( lu8g_getFontAscent ) },
+    { LSTRKEY( "getFontDescent" ),  LFUNCVAL( lu8g_getFontDescent ) },
+    { LSTRKEY( "getFontLineSpacing" ),  LFUNCVAL( lu8g_getFontLineSpacing ) },
+    { LSTRKEY( "getHeight" ),  LFUNCVAL( lu8g_getHeight ) },
+    { LSTRKEY( "getMode" ),  LFUNCVAL( lu8g_getMode ) },
+    { LSTRKEY( "getStrWidth" ), LFUNCVAL( lu8g_getStrWidth ) },
+    { LSTRKEY( "getWidth" ),  LFUNCVAL( lu8g_getWidth ) },
     { LSTRKEY( "nextPage" ),  LFUNCVAL( lu8g_nextPage ) },
-    { LSTRKEY( "sleepOn" ),  LFUNCVAL( lu8g_sleepOn ) },
-    { LSTRKEY( "sleepOff" ),  LFUNCVAL( lu8g_sleepOff ) },
+    { LSTRKEY( "setColorIndex" ),  LFUNCVAL( lu8g_setColorIndex ) },
+    { LSTRKEY( "setDefaultBackgroundColor" ),  LFUNCVAL( lu8g_setDefaultBackgroundColor ) },
+    { LSTRKEY( "setDefaultForegroundColor" ),  LFUNCVAL( lu8g_setDefaultForegroundColor ) },
+    { LSTRKEY( "setFont" ),  LFUNCVAL( lu8g_setFont ) },
+    { LSTRKEY( "setFontLineSpacingFactor" ),  LFUNCVAL( lu8g_setFontLineSpacingFactor ) },
+    { LSTRKEY( "setFontPosBaseline" ),  LFUNCVAL( lu8g_setFontPosBaseline ) },
+    { LSTRKEY( "setFontPosBottom" ),  LFUNCVAL( lu8g_setFontPosBottom ) },
+    { LSTRKEY( "setFontPosCenter" ),  LFUNCVAL( lu8g_setFontPosCenter ) },
+    { LSTRKEY( "setFontPosTop" ),  LFUNCVAL( lu8g_setFontPosTop ) },
+    { LSTRKEY( "setFontRefHeightAll" ),  LFUNCVAL( lu8g_setFontRefHeightAll ) },
+    { LSTRKEY( "setFontRefHeightExtendedText" ),  LFUNCVAL( lu8g_setFontRefHeightExtendedText ) },
+    { LSTRKEY( "setFontRefHeightText" ),  LFUNCVAL( lu8g_setFontRefHeightText ) },
     { LSTRKEY( "setRot90" ),  LFUNCVAL( lu8g_setRot90 ) },
     { LSTRKEY( "setRot180" ),  LFUNCVAL( lu8g_setRot180 ) },
     { LSTRKEY( "setRot270" ),  LFUNCVAL( lu8g_setRot270 ) },
+    { LSTRKEY( "setScale2x2" ),  LFUNCVAL( lu8g_setScale2x2 ) },
+    { LSTRKEY( "sleepOff" ),  LFUNCVAL( lu8g_sleepOff ) },
+    { LSTRKEY( "sleepOn" ),  LFUNCVAL( lu8g_sleepOn ) },
     { LSTRKEY( "undoRotation" ),  LFUNCVAL( lu8g_undoRotation ) },
-    { LSTRKEY( "getWidth" ),  LFUNCVAL( lu8g_getWidth ) },
-    { LSTRKEY( "getHeight" ),  LFUNCVAL( lu8g_getHeight ) },
+    { LSTRKEY( "undoScale" ),  LFUNCVAL( lu8g_undoScale ) },
     { LSTRKEY( "__gc" ),  LFUNCVAL( lu8g_close_display ) },
 #if LUA_OPTIMIZE_MEMORY > 0
     { LSTRKEY( "__index" ), LROVAL ( lu8g_display_map ) },
diff --git a/lua_modules/lm92/README.md b/lua_modules/lm92/README.md
new file mode 100644
index 00000000..261e1ebe
--- /dev/null
+++ b/lua_modules/lm92/README.md
@@ -0,0 +1,98 @@
+# LM92 module
+This module adds basic support for the LM92 +-0.33C 12bit+sign temperature sensor. More details in the [datasheet](http://www.ti.com/lit/ds/symlink/lm92.pdf).
+Works:
+- getting the temperature
+- entering the chip's to shutdown mode (350uA -> 5uA power consumption)
+- waking up the chip from shutdown
+
+##Require
+```lua
+LM92 = require("lm92")
+```
+## Release
+```lua
+LM92 = nil
+package.loaded["lm92"]=nil
+```
+
+##init()
+####Description
+Setting the i2c pins and address for lm92.
+
+####Syntax
+init(sda, scl, address)
+
+####Parameters
+sda: 1~12, IO index.<br />
+scl: 1~12, IO index.<br />
+address: 0x48~0x4b, i2c address (depends on tha A0~A1 pins)
+####Returns
+nil
+
+####Example
+```lua
+LM92 = require("lm92")
+gpio0 = 3
+gpio2 = 4
+sda = gpio0
+scl = gpio2
+addr = 0x48
+LM92.init(sda, scl,addr)
+```
+##getTemperature()
+####Description
+Returns the temperature register's content.
+
+####Syntax
+getTemperature()
+
+####Parameters
+-
+
+####Returns
+Temperature in degree Celsius.
+
+####Example
+```lua
+t = LM92.getTemperature()
+print("Got temperature: "..t.." C")
+```
+
+##wakeup()
+####Description
+Makes the chip exit the low power shutdown mode.
+
+####Syntax
+wakeup()
+
+####Parameters
+-
+
+####Returns
+-
+
+####Example
+```lua
+LM92.wakeup()
+tmr.delay( 1 * 1000 * 1000 )
+```
+
+##shutdown()
+####Description
+Makes the chip enter the low power shutdown mode.
+
+####Syntax
+shutdown()
+
+####Parameters
+-
+
+####Returns
+-
+
+####Example
+```lua
+LM92.shutdown()
+```
+#### TODO:
+- add full support of the features, including interrupt and critical alert support
diff --git a/lua_modules/lm92/lm92.lua b/lua_modules/lm92/lm92.lua
new file mode 100644
index 00000000..fcec7098
--- /dev/null
+++ b/lua_modules/lm92/lm92.lua
@@ -0,0 +1,94 @@
+-- ******************************************************
+-- LM92 module for ESP8266 with nodeMCU
+--
+-- Written by Levente Tamas <levente.tamas@navicron.com>
+--
+-- GNU LGPL, see https://www.gnu.org/copyleft/lesser.html
+-- ******************************************************
+
+-- Module Bits
+local moduleName = ...
+local M = {}
+_G[moduleName] = M
+
+-- Default ID
+local id = 0
+
+-- Local vars
+local address = 0
+
+-- read regs for len number of bytes
+-- return table with data
+local function read_reg(reg_addr, len)
+	local ret={}
+	local c
+	local x
+	i2c.start(id)
+	i2c.address(id, address ,i2c.TRANSMITTER)
+	i2c.write(id,reg_addr)
+	i2c.stop(id)
+	i2c.start(id)
+	i2c.address(id, address,i2c.RECEIVER)
+	c=i2c.read(id,len)
+	for x=1,len,1 do
+		tc=string.byte(c,x)
+		table.insert(ret,tc)
+	end
+	i2c.stop(id)
+	return ret
+end 
+
+--write reg with data table
+local function write_reg(reg_addr, data)
+	i2c.start(id)
+	i2c.address(id, address, i2c.TRANSMITTER)
+	i2c.write(id, reg_addr)
+	i2c.write(id, data)
+	i2c.stop(id)
+end 
+
+-- initialize i2c
+-- d: sda
+-- c: scl
+-- a: i2c addr 0x48|A1<<1|A0 (A0-A1: chip pins)
+function M.init(d,c,a)
+if (d ~= nil) and (c ~= nil) and (d >= 0) and (d <= 11) and (c >= 0) and ( c <= 11) and (d ~= l) and (a ~= nil) and (a >= 0x48) and (a <= 0x4b ) then
+		sda = d
+		scl = c 
+		address = a
+		i2c.start(id)
+		res = i2c.address(id, address, i2c.TRANSMITTER) --verify that the address is valid
+		i2c.stop(id)
+		if (res == false) then
+			print("device not found")
+			return nil
+		end
+		else 
+        print("i2c configuration failed") return nil
+      end
+	i2c.setup(id,sda,scl,i2c.SLOW)
+end
+
+-- Return the temperature data
+function M.getTemperature()
+	local temperature
+	local tmp=read_reg(0x00,2) --read 2 bytes from the temperature register
+	temperature=bit.rshift(tmp[1]*256+tmp[2],3) --lower 3 bits are status bits
+	if (temperature>=0x1000) then
+		temperature= temperature-0x2000 --convert the two's complement
+	end
+	return temperature * 0.0625
+end
+
+-- Put the LM92 into shutdown mode
+function M.shutdown()
+	write_reg(0x01,0x01)
+end
+
+-- Bring the LM92 out of shutdown mode
+function M.wakeup()
+	write_reg(0x01,0x00)
+end
+
+
+return M
\ No newline at end of file