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Error checking added in the example. Functions description added

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Javier Yáñez 2015-01-25 20:20:48 +01:00
parent 3ede2de2ea
commit 5a50f4e4ee
1 changed files with 35 additions and 5 deletions
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40
lua_modules/dht22/README.md
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@ -1,5 +1,8 @@
# DHT22 module # DHT22 module
This module is compatible with DHT22 and DHT21.
No need to use a resistor to connect the pin data of DHT22 to ESP8266.
## Example ## Example
```lua ```lua
PIN = 4 -- data pin, GPIO2 PIN = 4 -- data pin, GPIO2
@ -9,14 +12,41 @@ dht22.read(PIN)
t = dht22.getTemperature() t = dht22.getTemperature()
h = dht22.getHumidity() h = dht22.getHumidity()
-- temperature in degrees Celsius and Farenheit if h == -1 then
print("Temperature: "..(t/10).."."..(t%10).." deg C") print("Error reading from DHT22")
print("Temperature: "..(9 * t / 50 + 32).."."..(9 * t / 5 % 10).." deg F") else
-- temperature in degrees Celsius and Farenheit
print("Temperature: "..(t / 10).."."..(t % 10).." deg C")
print("Temperature: "..(9 * t / 50 + 32).."."..(9 * t / 5 % 10).." deg F")
-- humidity -- humidity
print("Humidity: "..(h/10).."."..(h%10).."%") print("Humidity: "..(h/10).."."..(h%10).."%")
end
-- release module -- release module
dht22 = nil dht22 = nil
package.loaded["dht22"]=nil package.loaded["dht22"]=nil
``` ```
## Functions
### read
read(pin)
Read humidity and temperature from DHT22.
**Parameters:**
* pin - ESP8266 pin connect to data pin in DHT22
### getHumidity
getHumidity()
Returns the humidity of the last reading.
**Returns:**
* last humidity reading in per thousand
### getTemperature
getTemperature()
Returns the temperature of the last reading.
**Returns:**
* last temperature reading in 0.1ºC