Refactoring of the code into files

credentials.lua.example

@@ -0,0 +1,2 @@
+SSID = "MyWifi"
+PASSWORD = "mypasswd"

dallas.lua

@@ -1,51 +1,6 @@
-function bxor(a,b)
-   local r = 0
-   for i = 0, 31 do
-      if ( a % 2 + b % 2 == 1 ) then
-         r = r + 2^i
-      end
-      a = a / 2
-      b = b / 2
-   end
-   return r
-end
-
 function getTemp()
-      addr = ow.reset_search(pin)
-      repeat
-        tmr.wdclr()
-      
-      if (addr ~= nil) then
-        crc = ow.crc8(string.sub(addr,1,7))
-        if (crc == addr:byte(8)) then
-          if ((addr:byte(1) == 0x10) or (addr:byte(1) == 0x28)) then
-                ow.reset(pin)
-                ow.select(pin, addr)
-                ow.write(pin, 0x44, 1)
-                tmr.delay(1000000)
-                present = ow.reset(pin)
-                ow.select(pin, addr)
-                ow.write(pin,0xBE, 1)
-                data = nil
-                data = string.char(ow.read(pin))
-                for i = 1, 8 do
-                  data = data .. string.char(ow.read(pin))
-                end
-                crc = ow.crc8(string.sub(data,1,8))
-                if (crc == data:byte(9)) then
-                   t = (data:byte(1) + data:byte(2) * 256)
-         if (t > 32768) then
-                    t = (bxor(t, 0xffff)) + 1
-                    t = (-1) * t
-                   end
-         t = t * 625
-                   lasttemp = t
-         print("Last temp: " .. lasttemp)
-                end                   
-                tmr.wdclr()
-          end
-        end
-      end
-      addr = ow.search(pin)
-      until(addr == nil)
+    t = require("ds18b20")
+    t.setup(9)
+    addrs = t.addrs()
+    lasttemp = t.read(nil,t.C)
 end

ds18b20.lua

@@ -0,0 +1,143 @@
+--------------------------------------------------------------------------------
+-- DS18B20 one wire module for NODEMCU
+-- NODEMCU TEAM
+-- LICENCE: http://opensource.org/licenses/MIT
+-- Vowstar <vowstar@nodemcu.com>
+-- 2015/02/14 sza2 <sza2trash@gmail.com> Fix for negative values
+--------------------------------------------------------------------------------
+
+-- Set module name as parameter of require
+local modname = ...
+local M = {}
+_G[modname] = M
+--------------------------------------------------------------------------------
+-- Local used variables
+--------------------------------------------------------------------------------
+-- DS18B20 dq pin
+local pin = nil
+-- DS18B20 default pin
+local defaultPin = 9
+--------------------------------------------------------------------------------
+-- Local used modules
+--------------------------------------------------------------------------------
+-- Table module
+local table = table
+-- String module
+local string = string
+-- One wire module
+local ow = ow
+-- Timer module
+local tmr = tmr
+-- Limited to local environment
+setfenv(1,M)
+--------------------------------------------------------------------------------
+-- Implementation
+--------------------------------------------------------------------------------
+C = 'C'
+F = 'F'
+K = 'K'
+function setup(dq)
+  pin = dq
+  if(pin == nil) then
+    pin = defaultPin
+  end
+  ow.setup(pin)
+end
+
+function addrs()
+  setup(pin)
+  tbl = {}
+  ow.reset_search(pin)
+  repeat
+    addr = ow.search(pin)
+    if(addr ~= nil) then
+      table.insert(tbl, addr)
+    end
+    tmr.wdclr()
+  until (addr == nil)
+  ow.reset_search(pin)
+  return tbl
+end
+
+function readNumber(addr, unit)
+  result = nil
+  setup(pin)
+  flag = false
+  if(addr == nil) then
+    ow.reset_search(pin)
+    count = 0
+    repeat
+      count = count + 1
+      addr = ow.search(pin)
+      tmr.wdclr()
+    until((addr ~= nil) or (count > 100))
+    ow.reset_search(pin)
+  end
+  if(addr == nil) then
+    return result
+  end
+  crc = ow.crc8(string.sub(addr,1,7))
+  if (crc == addr:byte(8)) then
+    if ((addr:byte(1) == 0x10) or (addr:byte(1) == 0x28)) then
+      -- print("Device is a DS18S20 family device.")
+      ow.reset(pin)
+      ow.select(pin, addr)
+      ow.write(pin, 0x44, 1)
+      -- tmr.delay(1000000)
+      present = ow.reset(pin)
+      ow.select(pin, addr)
+      ow.write(pin,0xBE,1)
+      -- print("P="..present)
+      data = nil
+      data = string.char(ow.read(pin))
+      for i = 1, 8 do
+        data = data .. string.char(ow.read(pin))
+      end
+      -- print(data:byte(1,9))
+      crc = ow.crc8(string.sub(data,1,8))
+      -- print("CRC="..crc)
+      if (crc == data:byte(9)) then
+        t = (data:byte(1) + data:byte(2) * 256)
+        if (t > 32767) then
+          t = t - 65536
+        end
+
+		if (addr:byte(1) == 0x28) then
+		  t = t * 625  -- DS18B20, 4 fractional bits
+		else
+		  t = t * 5000 -- DS18S20, 1 fractional bit
+		end
+
+        if(unit == nil or unit == 'C') then
+          -- do nothing
+        elseif(unit == 'F') then
+          t = t * 1.8 + 320000
+        elseif(unit == 'K') then
+          t = t + 2731500
+        else
+          return nil
+        end
+        t = t / 10000
+        return t
+      end
+      tmr.wdclr()
+    else
+    -- print("Device family is not recognized.")
+    end
+  else
+  -- print("CRC is not valid!")
+  end
+  return result
+end
+
+function read(addr, unit)
+  t = readNumber(addr, unit)
+  if (t == nil) then
+    return nil
+  else
+    return t
+  end
+end
+
+-- Return module table
+return M

server.lua

@@ -1,3 +1,9 @@
+temp = -999
+
+t = require("ds18b20")
+t.setup(4)
+addrs = t.addrs()
+
 mycounter=0
 srv=net.createServer(net.TCP) 
 srv:listen(80, function(conn) 
@@ -9,9 +15,13 @@ srv:listen(80, function(conn)
             m=""
         end
 
-        getTemp()
+        _temp = t.read(nil,t.C)
 
-        conn:send("<h1> Hello, this is Jeenas ESP8266.</h1><p>How are you today.<br> Count=" .. mycounter .. m .. "<br>Heap=" .. node.heap() .. "<br>Temp=" .. lasttemp)
+        if _temp ~= nil then
+           temp = _temp
+        end
+
+        conn:send("<h1> Hello, this is Jeenas ESP8266.</h1><p>How are you today.<br> Count=" .. mycounter .. m .. "<br>Heap=" .. node.heap() .. "<br>Temp=" .. temp)
     end) 
     conn:on("sent", function(conn) conn:close() end) 
 end)