Merge pull request nodemcu#329 from MarsTechHAN/patch-2

Add support to DHT11 and add some comments.

lua_modules/dht22/README.md

@@ -1,46 +1,78 @@
-# DHT22 module
+# DHTxx module
 
-This module is compatible with DHT22 and DHT21.  
-Supports nodemcu with or without floating point.  
+This module is compatible with DHT11, DHT21 and DHT22.  
 No need to use a resistor to connect the pin data of DHT22 to ESP8266.
 
-## Example  
+##Integer Verison[When using DHT11, Float version is useless...]
+### Example  
 ```lua
 PIN = 4 --  data pin, GPIO2
 
-dht22 = require("dht22")
-dht22.read(PIN)
-t = dht22.getTemperature()
-h = dht22.getHumidity()
+DHT= require("dht_lib")
+
+--dht.read11(PIN)
+DHT.read22(PIN)
+
+t = DHT.getTemperature()
+h = DHT.getHumidity()
 
 if h == nil then
-  print("Error reading from DHT22")
+  print("Error reading from DHT11/22")
 else
   -- temperature in degrees Celsius  and Farenheit
-  -- floating point and integer version:
+
   print("Temperature: "..((t-(t % 10)) / 10).."."..(t % 10).." deg C")
-  -- only integer version:
+
   print("Temperature: "..(9 * t / 50 + 32).."."..(9 * t / 5 % 10).." deg F")
-  -- only float point version:
-  print("Temperature: "..(9 * t / 50 + 32).." deg F")
 
   -- humidity
-  -- floating point and integer version
+
   print("Humidity: "..((h - (h % 10)) / 10).."."..(h % 10).."%")
 end
 
 -- release module
-dht22 = nil
-package.loaded["dht22"]=nil
+DHT = nil
+package.loaded["dht_lib"]=nil
 ```
-## Functions
-### read
-read(pin)  
-Read humidity and temperature from DHT22.
+##Float Verison
+###Example
+```lua
+PIN = 4 --  data pin, GPIO2
+
+DHT= require("dht_lib")
+
+--dht.read11(PIN)
+DHT.read22(PIN)
+
+t = DHT.getTemperature()
+h = DHT.getHumidity()
 
+if h == nil then
+  print("Error reading from DHT11/22")
+else
+  -- temperature in degrees Celsius  and Farenheit
+  -- floating point and integer version:
+  print("Temperature: "..t.." deg C")
+  print("Temperature: "..(9 * t / 50 + 32).." deg F")
+
+  -- humidity
+  print("Humidity: "..h.."%")
+end
+
+-- release module
+DHT = nil
+package.loaded["dht_lib"]=nil
+```
+## Functions
+### read11
+read11(pin)  
+Read humidity and temperature from DHT11.
+###read22
+read22(pin)
+Read humidity and temperature from DHT22/21.
 **Parameters:**
 
-* pin - ESP8266 pin connect to data pin in DHT22
+* pin - ESP8266 pin connect to data pin
 
 ### getHumidity
 getHumidity()  
@@ -54,5 +86,6 @@ getTemperature()
 Returns the temperature of the last reading.
 
 **Returns:**  
-* last temperature reading in 0.1ºC
+* last temperature reading in(dht22) 0.1ºC (dht11)1ºC
+*