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https://github.com/beegee-tokyo/dhtesp
Optimized DHT library for ESP32/ESP8266 using Arduino framework
https://github.com/beegee-tokyo/dhtesp
arduino-ide dht dht11 dht22 esp32 esp8266 espressif platformio
Last synced: 5 days ago
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Optimized DHT library for ESP32/ESP8266 using Arduino framework
- Host: GitHub
- URL: https://github.com/beegee-tokyo/dhtesp
- Owner: beegee-tokyo
- License: gpl-3.0
- Archived: true
- Created: 2018-01-07T07:24:31.000Z (about 7 years ago)
- Default Branch: master
- Last Pushed: 2023-04-14T04:16:15.000Z (almost 2 years ago)
- Last Synced: 2024-09-25T18:47:04.267Z (4 months ago)
- Topics: arduino-ide, dht, dht11, dht22, esp32, esp8266, espressif, platformio
- Language: C++
- Homepage:
- Size: 71.3 KB
- Stars: 232
- Watchers: 15
- Forks: 61
- Open Issues: 1
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
DHTesp [](https://github.com/beegee-tokyo/DHTesp/actions)
===
_**This library is no longer maintained**_
An Arduino library for reading the DHT family of temperature and humidity sensors.
Forked from [arduino-DHT](https://github.com/markruys/arduino-DHT)
Original written by Mark Ruys, .
Why did I clone this library instead of forking the original repo and push the changes?
When I searched through Github for DHT libraries, I found a lot of them, some of them offers additional functions, some of them only basic temperature and humidity values. I wanted to combine all interesting functions into one library. In addition, none of the DHT libraries I found were written to work without errors on the ESP32. For ESP32 (a multi core/ multi processing SOC) task switching must be disabled while reading data from the sensor.
Another problem I found is that many of the available libraries use the same naming (dht.h, dht.cpp), which easily leads to conflicts if different libraries are used for different platforms.
_**According to users, the library works as well with DHT33 and DHT44 sensors. But as I do not own these sensors, I cannot test and confirm it. However, if you want to use this sensors, you can do so by using `setup(pin, DHTesp::DHT22)` and it should work.
Please give me feedback in the issues if you successfull use these sensors.
Thank you**_
The library is tested as well on ESP8266 and should work on AVR boards as well.
Changes to the original library:
--------
- 2017-12-12: Renamed DHT class to DHTesp and filenames from dht.* to DHTesp.* to avoid conflicts with other libraries - beegee-tokyo, .
- 2017-12-12: Updated to work with ESP32 - beegee-tokyo, .
- 2017-12-12: Added function computeHeatIndex. Reference: [Adafruit DHT library](https://github.com/adafruit/DHT-sensor-library).
- 2017-12-14: Added function computeDewPoint. Reference: [idDHTLib](https://github.com/niesteszeck/idDHTLib).
- 2017-12-14: Added function getComfortRatio. Reference: [libDHT](https://github.com/ADiea/libDHT). (References about Human Comfort invalid)
- 2017-12-15: Added function computePerception. Reference: [WikiPedia Dew point==> Relationship to human comfort](https://en.wikipedia.org/wiki/Dew_point) - beegee-tokyo, .
- 2018-01-02: Added example for multiple sensors usage.
- 2018-01-03: Added function getTempAndHumidity which returns temperature and humidity in one call.
- 2018-01-03: Added retry in case the reading from the sensor fails with a timeout.
- 2018-01-08: Added ESP8266 (and probably AVR) compatibility.
- 2018-03-11: Updated DHT example
- 2018-06-19: Updated DHT example to distinguish between ESP8266 examples and ESP32 examples
- 2018-07-06: Fixed bug in ESP32 example
- 2018-07-17: Use correct field separator in keywords.txt
- 2019-03-07: Added computeAbsoluteHumidity which returns the absolute humidity in g/m³. Reference: [How to convert relative humidity to absolute humidity](https://carnotcycle.wordpress.com/2012/08/04/how-to-convert-relative-humidity-to-absolute-humidity/) kudos to [Wurstnase](https://github.com/Wurstnase)
- 2019-03-22: Fixed auto detection problem
- 2019-07-31: Make getPin() public, Updated ESP8266 example
- 2019-10-01: Using noInterrupts() & interrupts() instead of cli and sei
- 2019-10-05: Reduce CPU usage and add decimal part for DHT11 (thanks to Swiftyhu)
- 2019-10-06: Back to working version by removing the last commit
- 2021-02-20: Fix negative temperature problem (credits @helijunky)
Features
--------
- Support for DHT11 and DHT22, AM2302, RHT03
- Auto detect sensor model
- Determine heat index
- Determine dewpoint
- Determine thermal comfort:
* Empiric comfort function based on comfort profiles(parametric lines)
* Multiple comfort profiles possible. Default based on http://epb.apogee.net/res/refcomf.asp (References invalid)
* Determine if it's too cold, hot, humid, dry, based on current comfort profile
* More info at [Determining Thermal Comfort Using a Humidity and Temperature Sensor](https://www.azosensors.com/article.aspx?ArticleID=487)
- Determine human perception based on humidity, temperature and dew point according to Horstmeyer, Steve (2006-08-15). [Relative Humidity....Relative to What? The Dew Point Temperature...a better approach](http://www.shorstmeyer.com/wxfaqs/humidity/humidity.html)
Functions
-----
_**`void setup(uint8_t pin, DHT_MODEL_t model=AUTO_DETECT);`**_
- Call to initialize the interface, define the GPIO pin to which the sensor is connected and define the sensor type. Valid sensor types are:
- AUTO_DETECT Try to detect which sensor is connected (default if 2nd parameter is not used)
- DHT11
- DHT22
- AM2302 Packaged DHT22
- RHT03 Equivalent to DHT22
_**`void resetTimer();`**_
- Reset last time the sensor was read
_**`float getTemperature();`**_
- Get the temperature in degree Centigrade from the sensor
Either one of _`getTemperature()`_ or _`getHumidity()`_ or _`getTempAndHumidity()`_ initiates reading a value from the sensor if the last reading was older than the minimal refresh time of the sensor.
See example _`DHT_ESP32.ino`_ or _`DHT_Test.ino`_
_**`float getHumidity();`**_
- Get the humidity from the sensor
Either one of _`getTemperature()`_ or _`getHumidity()`_ or _`getTempAndHumidity()`_ initiates reading a value from the sensor if the last reading was older than the minimal refresh time of the sensor.
See example _`DHT_ESP32.ino`_ or _`DHT_Test.ino`_
_**`TempAndHumidity getTempAndHumidity();`**_
- Get the temperature and humidity from the sensor
Either one of _`getTemperature()`_ or _`getHumidity()`_ or _`getTempAndHumidity()`_ initiates reading a value from the sensor if the last reading was older than the minimal refresh time of the sensor.
Return value is a struct of type _`TempAndHumidity`_ with temperature and humidity as float values.
See example _`DHT_Multi.ino`_
_**`DHT_ERROR_t getStatus();`**_
- Get last error if reading from the sensor failed. Possible values are:
- ERROR_NONE no error occured
- ERROR_TIMEOUT timeout reading from the sensor
- ERROR_CHECKSUM checksum of received values doesn't match
_**`const char* getStatusString();`**_
- Get last error as a char *
_**`DHT_MODEL_t getModel()`**_
- Get detected (or defined) sensor type
_**`int getMinimumSamplingPeriod();`**_
- Get minimmum possible sampling period. For DHT11 this is 1000ms, for other sensors it is 2000ms
_**`int8_t getNumberOfDecimalsTemperature();`**_
- Get number of decimals in the temperature value. For DHT11 this is 0, for other sensors it is 1
_**`int8_t getLowerBoundTemperature();`**_
- Get lower temperature range of the sensor. For DHT11 this is 0 degree Centigrade, for other sensors this is -40 degree Centrigrade
_**`int8_t getUpperBoundTemperature();`**_
- Get upper temperature range of the sensor. For DHT11 this is 50 degree Centigrade, for other sensors this is 125 degree Centrigrade
_**`int8_t getNumberOfDecimalsHumidity();`**_
- Get number of decimals in the humidity value. This is always 0.
_**`int8_t getLowerBoundHumidity();`**_
- Get lower humidity range of the sensor. For DHT11 this is 20 percent, for other sensors this is 0 percent
_**`int8_t getUpperBoundHumidity();`**_
- Get upper temperature range of the sensor. For DHT11 this is 90 percent, for other sensors this is 100 percent
_**`static float toFahrenheit(float fromCelcius);`**_
- Convert Centrigrade value to Fahrenheit value
_**`static float toCelsius(float fromFahrenheit) { return (fromFahrenheit - 32.0) / 1.8; };`**_
- Convert Fahrenheit value to Centigrade value
_**`float computeHeatIndex(float temperature, float percentHumidity, bool isFahrenheit=false);`**_
- Compute the heat index. Default temperature is in Centrigrade.
_**`float computeDewPoint(float temperature, float percentHumidity, bool isFahrenheit=false);`**_
- Compute the dew point. Default temperature is in Centrigrade.
_**`float computeAbsoluteHumidity(float temperature, float percentHumidity, bool isFahrenheit=false);`**_
- Compute the absolute humidity in g/m³. Default temperature is in Centrigrade.
_**`float getComfortRatio(ComfortState& destComfStatus, float temperature, float percentHumidity, bool isFahrenheit=false);`**_
- Compute the comfort ratio. Default temperature is in Centrigrade. Return values:
0 -> OK
1 -> Too Hot
2 -> Too cold
4 -> Too dry
8 -> Too humid
9 -> Hot and humid
5 -> Hot and dry
10 -> Cold and humid
6 -> Cold and dry
_**`byte computePerception(float temperature, float percentHumidity, bool isFahrenheit=false);`**_
- Compute the human perception. Default temperature is in Centrigrade. Return values:
0 -> Dry
1 -> Very comfortable
2 -> Comfortable
3 -> Ok
4 -> Uncomfortable
5 -> Quite uncomfortable
6 -> Very uncomfortable
7 -> Severe uncomfortable
_**`uint8_t getPin(void);`**_
- Returns the assigned GPIO for this instance. Usefull when connecting multiple sensors
Usage
-----
See [examples](https://github.com/beegee-tokyo/DHTesp/blob/master/examples). For all the options, see [dhtesp.h](https://github.com/beegee-tokyo/DHTesp/blob/master/DHTesp.h).
Installation
------------
In Arduino IDE open Sketch->Include Library->Manage Libraries then search for _**DHT ESP**_
In PlatformIO open PlatformIO Home, switch to libraries and search for _**DHT ESP32**_. Or install the library in the terminal with _**`platformio lib install 2029`**_
For manual installation [download](https://github.com/beegee-tokyo/DHTesp/archive/master.zip) the archive, unzip it and place the DHTesp folder into the library directory.
In Arduino IDE this is usually _**`/libraries/`**_
In PlatformIO this is usually _**``**_