Added temperature measurement; but ESP is resetting due to RAM usage

ds18b20.lua

@@ -0,0 +1,138 @@
+--------------------------------------------------------------------------------
+-- 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 = 0
+F = 1
+K = 2
+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(unit == nil or unit == C) then
+          t = t * 625
+        elseif(unit == F) then
+          t = t * 1125 + 320000
+        elseif(unit == K) then
+          t = t * 625 + 2731500
+        else
+          return nil
+        end
+        t = t / 100
+        -- print("Temperature="..t1.."."..t2.." Centigrade")
+        -- result = t1.."."..t2
+        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

mqtt.lua

@@ -1,3 +1,7 @@
+-- Global variable
+t=nil
+mqttConnected = false
+
 -- MQTT extension
 function startMqtt()
     m = mqtt.Client("wordclock", 120)
@@ -34,18 +38,50 @@ function startMqtt()
     end)
 end
 
+function readTemp()
+  if (t ~= nil) then
+    addrs=t.addrs()
+    -- Total DS18B20 numbers
+    sensors=table.getn(addrs)
+    local temp1=0
+    if (sensors >= 1) then
+        temp1=t.read(addrs[1])
+    end
+    return temp1
+  else
+    return nil
+  end
+end
+
 function startMqttClient()
     if (mqttServer ~= nil and mqttPrefix ~= nil) then
         startMqtt()
         print "Started MQTT client"
+        if (file.open("ds18b20.lc")) then
+          t=require("ds18b20")
+          t.setup(2) -- GPIO4
+          readTemp() -- read once, to setup chip
+          print "Setup temperature"
+        end
+        
         oldBrightness=0
+        oldTemp=0
         tmr.alarm(5, 5001, 1 ,function()
-            if (oldBrightness ~= briPercent) then
-             m:publish(mqttPrefix .. "/brightness", tostring(briPercent), 0, 0)
-            else
-             m:publish(mqttPrefix .. "/heap", tostring(node.heap()), 0, 0)
+            if (mqttConnected) then
+                local temp = nil
+                if (t ~= nil) then
+                    temp=readTemp()
+                end
+                if (oldBrightness ~= briPercent) then
+                 m:publish(mqttPrefix .. "/brightness", tostring(briPercent), 0, 0)
+                elseif (temp ~= nil and temp ~= oldTemp) then
+                 oldTemp = temp
+                 m:publish(mqttPrefix .. "/temp", tostring(temp), 0, 0)
+                else
+                 m:publish(mqttPrefix .. "/heap", tostring(node.heap()), 0, 0)
+                end
+                oldBrightness = briPercent
             end
-            oldBrightness = briPercent
         end)
     end
 end