59 lines
1.3 KiB
Markdown
59 lines
1.3 KiB
Markdown
# DHT22 module
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This module is compatible with DHT22 and DHT21.
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Supports nodemcu with or without floating point.
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No need to use a resistor to connect the pin data of DHT22 to ESP8266.
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## Example
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```lua
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PIN = 4 -- data pin, GPIO2
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dht22 = require("dht22")
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dht22.read(PIN)
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t = dht22.getTemperature()
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h = dht22.getHumidity()
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if h == nil then
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print("Error reading from DHT22")
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else
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-- temperature in degrees Celsius and Farenheit
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-- floating point and integer version:
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print("Temperature: "..((t-(t % 10)) / 10).."."..(t % 10).." deg C")
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-- only integer version:
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print("Temperature: "..(9 * t / 50 + 32).."."..(9 * t / 5 % 10).." deg F")
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-- only float point version:
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print("Temperature: "..(9 * t / 50 + 32).." deg F")
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-- humidity
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-- floating point and integer version
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print("Humidity: "..((h - (h % 10)) / 10).."."..(h % 10).."%")
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end
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-- release module
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dht22 = nil
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package.loaded["dht22"]=nil
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```
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## Functions
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### read
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read(pin)
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Read humidity and temperature from DHT22.
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**Parameters:**
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* pin - ESP8266 pin connect to data pin in DHT22
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### getHumidity
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getHumidity()
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Returns the humidity of the last reading.
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**Returns:**
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* last humidity reading in per thousand
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### getTemperature
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getTemperature()
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Returns the temperature of the last reading.
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**Returns:**
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* last temperature reading in 0.1ºC
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