DHTesp

This library is no longer maintained

An Arduino library for reading the DHT family of temperature and humidity sensors.
Forked from arduino-DHT
Original written by Mark Ruys, [email protected].

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, [email protected].
• 2017-12-12: Updated to work with ESP32 - beegee-tokyo, [email protected].
• 2017-12-12: Added function computeHeatIndex. Reference: Adafruit DHT library.
• 2017-12-14: Added function computeDewPoint. Reference: idDHTLib.
• 2017-12-14: Added function getComfortRatio. Reference: libDHT. (References about Human Comfort invalid)
• 2017-12-15: Added function computePerception. Reference: WikiPedia Dew point==> Relationship to human comfort - beegee-tokyo, [email protected].
• 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 kudos to 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)
• 2022-12-09: Erase human based calculation (heat index, Fahrenheit-Celsius conversion, etc). Also delete comfort classification calculation

Features

• Support for DHT11 and DHT22, AM2302, RHT03
• Determine dewpoint
• Determine thermal comfort:
  • More info at Determining Thermal Comfort Using a Humidity and Temperature Sensor
• 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