Update CI action versions

Fix infinite loop on STM32F103

.github/ISSUE_TEMPLATE.md

@@ -0,0 +1,46 @@
+Thank you for opening an issue on an Adafruit Arduino library repository.  To
+improve the speed of resolution please review the following guidelines and
+common troubleshooting steps below before creating the issue:
+
+- **Do not use GitHub issues for troubleshooting projects and issues.**  Instead use
+  the forums at http://forums.adafruit.com to ask questions and troubleshoot why
+  something isn't working as expected.  In many cases the problem is a common issue
+  that you will more quickly receive help from the forum community.  GitHub issues
+  are meant for known defects in the code.  If you don't know if there is a defect
+  in the code then start with troubleshooting on the forum first.
+
+- **If following a tutorial or guide be sure you didn't miss a step.** Carefully
+  check all of the steps and commands to run have been followed.  Consult the
+  forum if you're unsure or have questions about steps in a guide/tutorial.
+
+- **For Arduino projects check these very common issues to ensure they don't apply**:
+
+  - For uploading sketches or communicating with the board make sure you're using
+    a **USB data cable** and **not** a **USB charge-only cable**.  It is sometimes
+    very hard to tell the difference between a data and charge cable!  Try using the
+    cable with other devices or swapping to another cable to confirm it is not
+    the problem.
+
+  - **Be sure you are supplying adequate power to the board.**  Check the specs of
+    your board and plug in an external power supply.  In many cases just
+    plugging a board into your computer is not enough to power it and other
+    peripherals.
+
+  - **Double check all soldering joints and connections.**  Flakey connections
+    cause many mysterious problems.  See the [guide to excellent soldering](https://learn.adafruit.com/adafruit-guide-excellent-soldering/tools) for examples of good solder joints.
+
+  - **Ensure you are using an official Arduino or Adafruit board.** We can't
+    guarantee a clone board will have the same functionality and work as expected
+    with this code and don't support them.
+
+If you're sure this issue is a defect in the code and checked the steps above
+please fill in the following fields to provide enough troubleshooting information.
+You may delete the guideline and text above to just leave the following details:
+
+- Arduino board:  **INSERT ARDUINO BOARD NAME/TYPE HERE**
+
+- Arduino IDE version (found in Arduino -> About Arduino menu):  **INSERT ARDUINO
+  VERSION HERE**
+
+- List the steps to reproduce the problem below (if possible attach a sketch or
+  copy the sketch code in too): **LIST REPRO STEPS BELOW**

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,26 @@
+Thank you for creating a pull request to contribute to Adafruit's GitHub code!
+Before you open the request please review the following guidelines and tips to
+help it be more easily integrated:
+
+- **Describe the scope of your change--i.e. what the change does and what parts
+  of the code were modified.**  This will help us understand any risks of integrating
+  the code.
+
+- **Describe any known limitations with your change.**  For example if the change
+  doesn't apply to a supported platform of the library please mention it.
+
+- **Please run any tests or examples that can exercise your modified code.**  We
+  strive to not break users of the code and running tests/examples helps with this
+  process.
+
+Thank you again for contributing!  We will try to test and integrate the change
+as soon as we can, but be aware we have many GitHub repositories to manage and
+can't immediately respond to every request.  There is no need to bump or check in
+on a pull request (it will clutter the discussion of the request).
+
+Also don't be worried if the request is closed or not integrated--sometimes the
+priorities of Adafruit's GitHub code (education, ease of use) might not match the
+priorities of the pull request.  Don't fret, the open source community thrives on
+forks and GitHub makes it easy to keep your changes in a forked repo.
+
+After reviewing the guidelines above you can delete this text from the pull request.

.github/workflows/githubci.yml

@@ -0,0 +1,32 @@
+name: Arduino Library CI
+
+on: [pull_request, push, repository_dispatch]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    
+    steps:
+    - uses: actions/setup-python@v4
+      with:
+        python-version: '3.x'
+    - uses: actions/checkout@v3
+    - uses: actions/checkout@v3
+      with:
+         repository: adafruit/ci-arduino
+         path: ci
+
+    - name: pre-install
+      run: bash ci/actions_install.sh
+
+    - name: test platforms
+      run: python3 ci/build_platform.py main_platforms
+
+    - name: clang
+      run: python3 ci/run-clang-format.py -e "ci/*" -e "bin/*" -r . 
+
+    - name: doxygen
+      env:
+        GH_REPO_TOKEN: ${{ secrets.GH_REPO_TOKEN }}
+        PRETTYNAME : "DHT sensor library"
+      run: bash ci/doxy_gen_and_deploy.sh

.gitignore

@@ -0,0 +1,8 @@
+# osx
+.DS_Store
+
+# doxygen
+Doxyfile*
+doxygen_sqlite3.db
+html
+*.tmp

CONTRIBUTING.md

@@ -0,0 +1,13 @@
+# Contribution Guidlines
+
+This library is the culmination of the expertise of many members of the open source community who have dedicated their time and hard work. The best way to ask for help or propose a new idea is to [create a new issue](https://github.com/adafruit/DHT-sensor-library/issues/new) while creating a Pull Request with your code changes allows you to share your own innovations with the rest of the community.
+
+The following are some guidelines to observe when creating issues or PRs:
+
+- Be friendly; it is important that we can all enjoy a safe space as we are all working on the same project and it is okay for people to have different ideas
+
+- [Use code blocks](https://github.com/adam-p/markdown-here/wiki/Markdown-Cheatsheet#code); it helps us help you when we can read your code! On that note also refrain from pasting more than 30 lines of code in a post, instead [create a gist](https://gist.github.com/) if you need to share large snippets
+
+- Use reasonable titles; refrain from using overly long or capitalized titles as they are usually annoying and do little to encourage others to help :smile:
+
+- Be detailed; refrain from mentioning code problems without sharing your source code and always give information regarding your board and version of the library

DHT.cpp

@@ -1,35 +1,87 @@
-/* DHT library
-
-MIT license
-written by Adafruit Industries
-*/
+/*!
+ *  @file DHT.cpp
+ *
+ *  @mainpage DHT series of low cost temperature/humidity sensors.
+ *
+ *  @section intro_sec Introduction
+ *
+ *  This is a library for DHT series of low cost temperature/humidity sensors.
+ *
+ *  You must have Adafruit Unified Sensor Library library installed to use this
+ * class.
+ *
+ *  Adafruit invests time and resources providing this open source code,
+ *  please support Adafruit andopen-source hardware by purchasing products
+ *  from Adafruit!
+ *
+ *  @section author Author
+ *
+ *  Written by Adafruit Industries.
+ *
+ *  @section license License
+ *
+ *  MIT license, all text above must be included in any redistribution
+ */
 
 #include "DHT.h"
 
-#define MIN_INTERVAL 2000
+#define MIN_INTERVAL 2000 /**< min interval value */
+#define TIMEOUT                                                                \
+  UINT32_MAX /**< Used programmatically for timeout.                           \
+                   Not a timeout duration. Type: uint32_t. */
 
+/*!
+ *  @brief  Instantiates a new DHT class
+ *  @param  pin
+ *          pin number that sensor is connected
+ *  @param  type
+ *          type of sensor
+ *  @param  count
+ *          number of sensors
+ */
 DHT::DHT(uint8_t pin, uint8_t type, uint8_t count) {
+  (void)count; // Workaround to avoid compiler warning.
   _pin = pin;
   _type = type;
+#ifdef __AVR
   _bit = digitalPinToBitMask(pin);
   _port = digitalPinToPort(pin);
-  _maxcycles = microsecondsToClockCycles(1000);  // 1 millisecond timeout for
-                                                 // reading pulses from DHT sensor.
+#endif
+  _maxcycles =
+      microsecondsToClockCycles(1000); // 1 millisecond timeout for
+                                       // reading pulses from DHT sensor.
   // Note that count is now ignored as the DHT reading algorithm adjusts itself
-  // basd on the speed of the processor.
+  // based on the speed of the processor.
 }
 
-void DHT::begin(void) {
+/*!
+ *  @brief  Setup sensor pins and set pull timings
+ *  @param  usec
+ *          Optionally pass pull-up time (in microseconds) before DHT reading
+ *starts. Default is 55 (see function declaration in DHT.h).
+ */
+void DHT::begin(uint8_t usec) {
   // set up the pins!
   pinMode(_pin, INPUT_PULLUP);
   // Using this value makes sure that millis() - lastreadtime will be
   // >= MIN_INTERVAL right away. Note that this assignment wraps around,
   // but so will the subtraction.
-  _lastreadtime = -MIN_INTERVAL;
-  DEBUG_PRINT("Max clock cycles: "); DEBUG_PRINTLN(_maxcycles, DEC);
+  _lastreadtime = millis() - MIN_INTERVAL;
+  DEBUG_PRINT("DHT max clock cycles: ");
+  DEBUG_PRINTLN(_maxcycles, DEC);
+  pullTime = usec;
 }
 
-//boolean S == Scale.  True == Fahrenheit; False == Celcius
+/*!
+ *  @brief  Read temperature
+ *  @param  S
+ *          Scale. Boolean value:
+ *					- true = Fahrenheit
+ *					- false = Celcius
+ *  @param  force
+ *          true if in force mode
+ *	@return Temperature value in selected scale
+ */
 float DHT::readTemperature(bool S, bool force) {
   float f = NAN;
 
@@ -37,20 +89,32 @@ float DHT::readTemperature(bool S, bool force) {
     switch (_type) {
     case DHT11:
       f = data[2];
-      if(S) {
+      if (data[3] & 0x80) {
+        f = -1 - f;
+      }
+      f += (data[3] & 0x0f) * 0.1;
+      if (S) {
+        f = convertCtoF(f);
+      }
+      break;
+    case DHT12:
+      f = data[2];
+      f += (data[3] & 0x0f) * 0.1;
+      if (data[2] & 0x80) {
+        f *= -1;
+      }
+      if (S) {
         f = convertCtoF(f);
       }
       break;
     case DHT22:
     case DHT21:
-      f = data[2] & 0x7F;
-      f *= 256;
-      f += data[3];
+      f = ((word)(data[2] & 0x7F)) << 8 | data[3];
       f *= 0.1;
       if (data[2] & 0x80) {
         f *= -1;
       }
-      if(S) {
+      if (S) {
         f = convertCtoF(f);
       }
       break;
@@ -59,26 +123,39 @@ float DHT::readTemperature(bool S, bool force) {
   return f;
 }
 
-float DHT::convertCtoF(float c) {
-  return c * 1.8 + 32;
-}
+/*!
+ *  @brief  Converts Celcius to Fahrenheit
+ *  @param  c
+ *					value in Celcius
+ *	@return float value in Fahrenheit
+ */
+float DHT::convertCtoF(float c) { return c * 1.8 + 32; }
 
-float DHT::convertFtoC(float f) {
-  return (f - 32) * 0.55555;
-}
+/*!
+ *  @brief  Converts Fahrenheit to Celcius
+ *  @param  f
+ *					value in Fahrenheit
+ *	@return float value in Celcius
+ */
+float DHT::convertFtoC(float f) { return (f - 32) * 0.55555; }
 
+/*!
+ *  @brief  Read Humidity
+ *  @param  force
+ *					force read mode
+ *	@return float value - humidity in percent
+ */
 float DHT::readHumidity(bool force) {
   float f = NAN;
-  if (read()) {
+  if (read(force)) {
     switch (_type) {
     case DHT11:
-      f = data[0];
+    case DHT12:
+      f = data[0] + data[1] * 0.1;
       break;
     case DHT22:
     case DHT21:
-      f = data[0];
-      f *= 256;
-      f += data[1];
+      f = ((word)data[0]) << 8 | data[1];
       f *= 0.1;
       break;
     }
@@ -86,43 +163,76 @@ float DHT::readHumidity(bool force) {
   return f;
 }
 
-//boolean isFahrenheit: True == Fahrenheit; False == Celcius
-float DHT::computeHeatIndex(float temperature, float percentHumidity, bool isFahrenheit) {
-  // Using both Rothfusz and Steadman's equations
-  // http://www.wpc.ncep.noaa.gov/html/heatindex_equation.shtml
+/*!
+ *  @brief  Compute Heat Index
+ *          Simplified version that reads temp and humidity from sensor
+ *  @param  isFahrenheit
+ * 					true if fahrenheit, false if celcius
+ *(default true)
+ *	@return float heat index
+ */
+float DHT::computeHeatIndex(bool isFahrenheit) {
+  float hi = computeHeatIndex(readTemperature(isFahrenheit), readHumidity(),
+                              isFahrenheit);
+  return hi;
+}
+
+/*!
+ *  @brief  Compute Heat Index
+ *  				Using both Rothfusz and Steadman's equations
+ *					(http://www.wpc.ncep.noaa.gov/html/heatindex_equation.shtml)
+ *  @param  temperature
+ *          temperature in selected scale
+ *  @param  percentHumidity
+ *          humidity in percent
+ *  @param  isFahrenheit
+ * 					true if fahrenheit, false if celcius
+ *	@return float heat index
+ */
+float DHT::computeHeatIndex(float temperature, float percentHumidity,
+                            bool isFahrenheit) {
   float hi;
 
   if (!isFahrenheit)
     temperature = convertCtoF(temperature);
 
-  hi = 0.5 * (temperature + 61.0 + ((temperature - 68.0) * 1.2) + (percentHumidity * 0.094)); 
+  hi = 0.5 * (temperature + 61.0 + ((temperature - 68.0) * 1.2) +
+              (percentHumidity * 0.094));
 
   if (hi > 79) {
-    hi = -42.379 +
-             2.04901523 * temperature +
-            10.14333127 * percentHumidity +
-            -0.22475541 * temperature*percentHumidity +
-            -0.00683783 * pow(temperature, 2) +
-            -0.05481717 * pow(percentHumidity, 2) +
-             0.00122874 * pow(temperature, 2) * percentHumidity +
-             0.00085282 * temperature*pow(percentHumidity, 2) +
-            -0.00000199 * pow(temperature, 2) * pow(percentHumidity, 2);
+    hi = -42.379 + 2.04901523 * temperature + 10.14333127 * percentHumidity +
+         -0.22475541 * temperature * percentHumidity +
+         -0.00683783 * pow(temperature, 2) +
+         -0.05481717 * pow(percentHumidity, 2) +
+         0.00122874 * pow(temperature, 2) * percentHumidity +
+         0.00085282 * temperature * pow(percentHumidity, 2) +
+         -0.00000199 * pow(temperature, 2) * pow(percentHumidity, 2);
 
-    if((percentHumidity < 13) && (temperature >= 80.0) && (temperature <= 112.0))
-      hi -= ((13.0 - percentHumidity) * 0.25) * sqrt((17.0 - abs(temperature - 95.0)) * 0.05882);
+    if ((percentHumidity < 13) && (temperature >= 80.0) &&
+        (temperature <= 112.0))
+      hi -= ((13.0 - percentHumidity) * 0.25) *
+            sqrt((17.0 - abs(temperature - 95.0)) * 0.05882);
 
-    else if((percentHumidity > 85.0) && (temperature >= 80.0) && (temperature <= 87.0))
+    else if ((percentHumidity > 85.0) && (temperature >= 80.0) &&
+             (temperature <= 87.0))
       hi += ((percentHumidity - 85.0) * 0.1) * ((87.0 - temperature) * 0.2);
   }
 
   return isFahrenheit ? hi : convertFtoC(hi);
 }
 
-boolean DHT::read(bool force) {
+/*!
+ *  @brief  Read value from sensor or return last one from less than two
+ *seconds.
+ *  @param  force
+ *          true if using force mode
+ *	@return float value
+ */
+bool DHT::read(bool force) {
   // Check if sensor was read less than two seconds ago and return early
   // to use last reading.
   uint32_t currenttime = millis();
-  if (!force && ((currenttime - _lastreadtime) < 2000)) {
+  if (!force && ((currenttime - _lastreadtime) < MIN_INTERVAL)) {
     return _lastresult; // return last correct measurement
   }
   _lastreadtime = currenttime;
@@ -130,42 +240,55 @@ boolean DHT::read(bool force) {
   // Reset 40 bits of received data to zero.
   data[0] = data[1] = data[2] = data[3] = data[4] = 0;
 
+#if defined(ESP8266)
+  yield(); // Handle WiFi / reset software watchdog
+#endif
+
   // Send start signal.  See DHT datasheet for full signal diagram:
   //   http://www.adafruit.com/datasheets/Digital%20humidity%20and%20temperature%20sensor%20AM2302.pdf
 
   // Go into high impedence state to let pull-up raise data line level and
   // start the reading process.
-  digitalWrite(_pin, HIGH);
-  delay(250);
+  pinMode(_pin, INPUT_PULLUP);
+  delay(1);
 
-  // First set data line low for 20 milliseconds.
+  // First set data line low for a period according to sensor type
   pinMode(_pin, OUTPUT);
   digitalWrite(_pin, LOW);
-  delay(20);
+  switch (_type) {
+  case DHT22:
+  case DHT21:
+    delayMicroseconds(1100); // data sheet says "at least 1ms"
+    break;
+  case DHT11:
+  default:
+    delay(20); // data sheet says at least 18ms, 20ms just to be safe
+    break;
+  }
 
   uint32_t cycles[80];
   {
-    // Turn off interrupts temporarily because the next sections are timing critical
-    // and we don't want any interruptions.
-    InterruptLock lock;
-
     // End the start signal by setting data line high for 40 microseconds.
-    digitalWrite(_pin, HIGH);
-    delayMicroseconds(40);
+    pinMode(_pin, INPUT_PULLUP);
+
+    // Delay a moment to let sensor pull data line low.
+    delayMicroseconds(pullTime);
 
     // Now start reading the data line to get the value from the DHT sensor.
-    pinMode(_pin, INPUT_PULLUP);
-    delayMicroseconds(10);  // Delay a bit to let sensor pull data line low.
+
+    // Turn off interrupts temporarily because the next sections
+    // are timing critical and we don't want any interruptions.
+    InterruptLock lock;
 
     // First expect a low signal for ~80 microseconds followed by a high signal
     // for ~80 microseconds again.
-    if (expectPulse(LOW) == 0) {
-      DEBUG_PRINTLN(F("Timeout waiting for start signal low pulse."));
+    if (expectPulse(LOW) == TIMEOUT) {
+      DEBUG_PRINTLN(F("DHT timeout waiting for start signal low pulse."));
       _lastresult = false;
       return _lastresult;
     }
-    if (expectPulse(HIGH) == 0) {
-      DEBUG_PRINTLN(F("Timeout waiting for start signal high pulse."));
+    if (expectPulse(HIGH) == TIMEOUT) {
+      DEBUG_PRINTLN(F("DHT timeout waiting for start signal high pulse."));
       _lastresult = false;
       return _lastresult;
     }
@@ -176,50 +299,54 @@ boolean DHT::read(bool force) {
     // then it's a 1.  We measure the cycle count of the initial 50us low pulse
     // and use that to compare to the cycle count of the high pulse to determine
     // if the bit is a 0 (high state cycle count < low state cycle count), or a
-    // 1 (high state cycle count > low state cycle count). Note that for speed all
-    // the pulses are read into a array and then examined in a later step.
-    for (int i=0; i<80; i+=2) {
-      cycles[i]   = expectPulse(LOW);
-      cycles[i+1] = expectPulse(HIGH);
+    // 1 (high state cycle count > low state cycle count). Note that for speed
+    // all the pulses are read into a array and then examined in a later step.
+    for (int i = 0; i < 80; i += 2) {
+      cycles[i] = expectPulse(LOW);
+      cycles[i + 1] = expectPulse(HIGH);
     }
   } // Timing critical code is now complete.
 
   // Inspect pulses and determine which ones are 0 (high state cycle count < low
   // state cycle count), or 1 (high state cycle count > low state cycle count).
-  for (int i=0; i<40; ++i) {
-    uint32_t lowCycles  = cycles[2*i];
-    uint32_t highCycles = cycles[2*i+1];
-    if ((lowCycles == 0) || (highCycles == 0)) {
-      DEBUG_PRINTLN(F("Timeout waiting for pulse."));
+  for (int i = 0; i < 40; ++i) {
+    uint32_t lowCycles = cycles[2 * i];
+    uint32_t highCycles = cycles[2 * i + 1];
+    if ((lowCycles == TIMEOUT) || (highCycles == TIMEOUT)) {
+      DEBUG_PRINTLN(F("DHT timeout waiting for pulse."));
       _lastresult = false;
       return _lastresult;
     }
-    data[i/8] <<= 1;
+    data[i / 8] <<= 1;
     // Now compare the low and high cycle times to see if the bit is a 0 or 1.
     if (highCycles > lowCycles) {
       // High cycles are greater than 50us low cycle count, must be a 1.
-      data[i/8] |= 1;
+      data[i / 8] |= 1;
     }
     // Else high cycles are less than (or equal to, a weird case) the 50us low
     // cycle count so this must be a zero.  Nothing needs to be changed in the
     // stored data.
   }
 
-  DEBUG_PRINTLN(F("Received:"));
-  DEBUG_PRINT(data[0], HEX); DEBUG_PRINT(F(", "));
-  DEBUG_PRINT(data[1], HEX); DEBUG_PRINT(F(", "));
-  DEBUG_PRINT(data[2], HEX); DEBUG_PRINT(F(", "));
-  DEBUG_PRINT(data[3], HEX); DEBUG_PRINT(F(", "));
-  DEBUG_PRINT(data[4], HEX); DEBUG_PRINT(F(" =? "));
+  DEBUG_PRINTLN(F("Received from DHT:"));
+  DEBUG_PRINT(data[0], HEX);
+  DEBUG_PRINT(F(", "));
+  DEBUG_PRINT(data[1], HEX);
+  DEBUG_PRINT(F(", "));
+  DEBUG_PRINT(data[2], HEX);
+  DEBUG_PRINT(F(", "));
+  DEBUG_PRINT(data[3], HEX);
+  DEBUG_PRINT(F(", "));
+  DEBUG_PRINT(data[4], HEX);
+  DEBUG_PRINT(F(" =? "));
   DEBUG_PRINTLN((data[0] + data[1] + data[2] + data[3]) & 0xFF, HEX);
 
   // Check we read 40 bits and that the checksum matches.
   if (data[4] == ((data[0] + data[1] + data[2] + data[3]) & 0xFF)) {
     _lastresult = true;
     return _lastresult;
-  }
-  else {
-    DEBUG_PRINTLN(F("Checksum failure!"));
+  } else {
+    DEBUG_PRINTLN(F("DHT checksum failure!"));
     _lastresult = false;
     return _lastresult;
   }
@@ -233,25 +360,31 @@ boolean DHT::read(bool force) {
 // in the very latest IDE versions):
 //   https://github.com/arduino/Arduino/blob/master/hardware/arduino/avr/cores/arduino/wiring_pulse.c
 uint32_t DHT::expectPulse(bool level) {
+// F_CPU is not be known at compile time on platforms such as STM32F103.
+// The preprocessor seems to evaluate it to zero in that case.
+#if (F_CPU > 16000000L) || (F_CPU == 0L)
   uint32_t count = 0;
-  // On AVR platforms use direct GPIO port access as it's much faster and better
-  // for catching pulses that are 10's of microseconds in length:
-  #ifdef __AVR
-    uint8_t portState = level ? _bit : 0;
-    while ((*portInputRegister(_port) & _bit) == portState) {
-      if (count++ >= _maxcycles) {
-        return 0; // Exceeded timeout, fail.
-      }
+#else
+  uint16_t count = 0; // To work fast enough on slower AVR boards
+#endif
+// On AVR platforms use direct GPIO port access as it's much faster and better
+// for catching pulses that are 10's of microseconds in length:
+#ifdef __AVR
+  uint8_t portState = level ? _bit : 0;
+  while ((*portInputRegister(_port) & _bit) == portState) {
+    if (count++ >= _maxcycles) {
+      return TIMEOUT; // Exceeded timeout, fail.
     }
-  // Otherwise fall back to using digitalRead (this seems to be necessary on ESP8266
-  // right now, perhaps bugs in direct port access functions?).
-  #else
-    while (digitalRead(_pin) == level) {
-      if (count++ >= _maxcycles) {
-        return 0; // Exceeded timeout, fail.
-      }
+  }
+// Otherwise fall back to using digitalRead (this seems to be necessary on
+// ESP8266 right now, perhaps bugs in direct port access functions?).
+#else
+  while (digitalRead(_pin) == level) {
+    if (count++ >= _maxcycles) {
+      return TIMEOUT; // Exceeded timeout, fail.
     }
-  #endif
+  }
+#endif
 
   return count;
 }

DHT.h

@@ -1,70 +1,109 @@
-/* DHT library
+/*!
+ *  @file DHT.h
+ *
+ *  This is a library for DHT series of low cost temperature/humidity sensors.
+ *
+ *  You must have Adafruit Unified Sensor Library library installed to use this
+ * class.
+ *
+ *  Adafruit invests time and resources providing this open source code,
+ *  please support Adafruit andopen-source hardware by purchasing products
+ *  from Adafruit!
+ *
+ *  Written by Adafruit Industries.
+ *
+ *  MIT license, all text above must be included in any redistribution
+ */
 
-MIT license
-written by Adafruit Industries
-*/
 #ifndef DHT_H
 #define DHT_H
 
-#if ARDUINO >= 100
- #include "Arduino.h"
-#else
- #include "WProgram.h"
-#endif
+#include "Arduino.h"
 
-
-// Uncomment to enable printing out nice debug messages.
+/* Uncomment to enable printing out nice debug messages. */
 //#define DHT_DEBUG
 
-// Define where debug output will be printed.
-#define DEBUG_PRINTER Serial
+#define DEBUG_PRINTER                                                          \
+  Serial /**< Define where debug output will be printed.                       \
+          */
 
-// Setup debug printing macros.
+/* Setup debug printing macros. */
 #ifdef DHT_DEBUG
-  #define DEBUG_PRINT(...) { DEBUG_PRINTER.print(__VA_ARGS__); }
-  #define DEBUG_PRINTLN(...) { DEBUG_PRINTER.println(__VA_ARGS__); }
+#define DEBUG_PRINT(...)                                                       \
+  { DEBUG_PRINTER.print(__VA_ARGS__); }
+#define DEBUG_PRINTLN(...)                                                     \
+  { DEBUG_PRINTER.println(__VA_ARGS__); }
 #else
-  #define DEBUG_PRINT(...) {}
-  #define DEBUG_PRINTLN(...) {}
+#define DEBUG_PRINT(...)                                                       \
+  {} /**< Debug Print Placeholder if Debug is disabled */
+#define DEBUG_PRINTLN(...)                                                     \
+  {} /**< Debug Print Line Placeholder if Debug is disabled */
 #endif
 
-// Define types of sensors.
-#define DHT11 11
-#define DHT22 22
-#define DHT21 21
-#define AM2301 21
+/* Define types of sensors. */
+static const uint8_t DHT11{11};  /**< DHT TYPE 11 */
+static const uint8_t DHT12{12};  /**< DHY TYPE 12 */
+static const uint8_t DHT21{21};  /**< DHT TYPE 21 */
+static const uint8_t DHT22{22};  /**< DHT TYPE 22 */
+static const uint8_t AM2301{21}; /**< AM2301 */
 
+#if defined(TARGET_NAME) && (TARGET_NAME == ARDUINO_NANO33BLE)
+#ifndef microsecondsToClockCycles
+/*!
+ * As of 7 Sep 2020 the Arduino Nano 33 BLE boards do not have
+ * microsecondsToClockCycles defined.
+ */
+#define microsecondsToClockCycles(a) ((a) * (SystemCoreClock / 1000000L))
+#endif
+#endif
 
+/*!
+ *  @brief  Class that stores state and functions for DHT
+ */
 class DHT {
-  public:
-   DHT(uint8_t pin, uint8_t type, uint8_t count=6);
-   void begin(void);
-   float readTemperature(bool S=false, bool force=false);
-   float convertCtoF(float);
-   float convertFtoC(float);
-   float computeHeatIndex(float temperature, float percentHumidity, bool isFahrenheit=true);
-   float readHumidity(bool force=false);
-   boolean read(bool force=false);
+public:
+  DHT(uint8_t pin, uint8_t type, uint8_t count = 6);
+  void begin(uint8_t usec = 55);
+  float readTemperature(bool S = false, bool force = false);
+  float convertCtoF(float);
+  float convertFtoC(float);
+  float computeHeatIndex(bool isFahrenheit = true);
+  float computeHeatIndex(float temperature, float percentHumidity,
+                         bool isFahrenheit = true);
+  float readHumidity(bool force = false);
+  bool read(bool force = false);
 
- private:
+private:
   uint8_t data[5];
-  uint8_t _pin, _type, _bit, _port;
+  uint8_t _pin, _type;
+#ifdef __AVR
+  // Use direct GPIO access on an 8-bit AVR so keep track of the port and
+  // bitmask for the digital pin connected to the DHT.  Other platforms will use
+  // digitalRead.
+  uint8_t _bit, _port;
+#endif
   uint32_t _lastreadtime, _maxcycles;
   bool _lastresult;
+  uint8_t pullTime; // Time (in usec) to pull up data line before reading
 
   uint32_t expectPulse(bool level);
-
 };
 
+/*!
+ *  @brief  Class that defines Interrupt Lock Avaiability
+ */
 class InterruptLock {
-  public:
-   InterruptLock() {
+public:
+  InterruptLock() {
+#if !defined(ARDUINO_ARCH_NRF52)
     noInterrupts();
-   }
-   ~InterruptLock() {
+#endif
+  }
+  ~InterruptLock() {
+#if !defined(ARDUINO_ARCH_NRF52)
     interrupts();
-   }
-
+#endif
+  }
 };
 
 #endif

DHT_U.cpp

@@ -0,0 +1,239 @@
+/*!
+ *  @file DHT_U.cpp
+ *
+ *  Temperature & Humidity Unified Sensor Library
+ *
+ *  This is a library for DHT series of low cost temperature/humidity sensors.
+ *
+ *  You must have Adafruit Unified Sensor Library library installed to use this
+ * class.
+ *
+ *  Adafruit invests time and resources providing this open source code,
+ *  please support Adafruit andopen-source hardware by purchasing products
+ *  from Adafruit!
+ */
+#include "DHT_U.h"
+
+/*!
+ *  @brief  Instantiates a new DHT_Unified class
+ *  @param  pin
+ *          pin number that sensor is connected
+ *  @param  type
+ *          type of sensor
+ *  @param  count
+ *          number of sensors
+ *  @param  tempSensorId
+ *          temperature sensor id
+ *  @param  humiditySensorId
+ *          humidity sensor id
+ */
+DHT_Unified::DHT_Unified(uint8_t pin, uint8_t type, uint8_t count,
+                         int32_t tempSensorId, int32_t humiditySensorId)
+    : _dht(pin, type, count), _type(type), _temp(this, tempSensorId),
+      _humidity(this, humiditySensorId) {}
+
+/*!
+ *  @brief  Setup sensor (calls begin on It)
+ */
+void DHT_Unified::begin() { _dht.begin(); }
+
+/*!
+ *  @brief  Sets sensor name
+ *  @param  sensor
+ *          Sensor that will be set
+ */
+void DHT_Unified::setName(sensor_t *sensor) {
+  switch (_type) {
+  case DHT11:
+    strncpy(sensor->name, "DHT11", sizeof(sensor->name) - 1);
+    break;
+  case DHT12:
+    strncpy(sensor->name, "DHT12", sizeof(sensor->name) - 1);
+    break;
+  case DHT21:
+    strncpy(sensor->name, "DHT21", sizeof(sensor->name) - 1);
+    break;
+  case DHT22:
+    strncpy(sensor->name, "DHT22", sizeof(sensor->name) - 1);
+    break;
+  default:
+    // TODO: Perhaps this should be an error?  However main DHT library doesn't
+    // enforce restrictions on the sensor type value.  Pick a generic name for
+    // now.
+    strncpy(sensor->name, "DHT?", sizeof(sensor->name) - 1);
+    break;
+  }
+  sensor->name[sizeof(sensor->name) - 1] = 0;
+}
+
+/*!
+ *  @brief  Sets Minimum Delay Value
+ *  @param  sensor
+ *          Sensor that will be set
+ */
+void DHT_Unified::setMinDelay(sensor_t *sensor) {
+  switch (_type) {
+  case DHT11:
+    sensor->min_delay = 1000000L; // 1 second (in microseconds)
+    break;
+  case DHT12:
+    sensor->min_delay = 2000000L; // 2 second (in microseconds)
+    break;
+  case DHT21:
+    sensor->min_delay = 2000000L; // 2 seconds (in microseconds)
+    break;
+  case DHT22:
+    sensor->min_delay = 2000000L; // 2 seconds (in microseconds)
+    break;
+  default:
+    // Default to slowest sample rate in case of unknown type.
+    sensor->min_delay = 2000000L; // 2 seconds (in microseconds)
+    break;
+  }
+}
+
+/*!
+ *  @brief  Instantiates a new DHT_Unified Temperature Class
+ *  @param  parent
+ *          Parent Sensor
+ *  @param  id
+ *          Sensor id
+ */
+DHT_Unified::Temperature::Temperature(DHT_Unified *parent, int32_t id)
+    : _parent(parent), _id(id) {}
+
+/*!
+ *  @brief  Reads the sensor and returns the data as a sensors_event_t
+ *  @param  event
+ *  @return always returns true
+ */
+bool DHT_Unified::Temperature::getEvent(sensors_event_t *event) {
+  // Clear event definition.
+  memset(event, 0, sizeof(sensors_event_t));
+  // Populate sensor reading values.
+  event->version = sizeof(sensors_event_t);
+  event->sensor_id = _id;
+  event->type = SENSOR_TYPE_AMBIENT_TEMPERATURE;
+  event->timestamp = millis();
+  event->temperature = _parent->_dht.readTemperature();
+
+  return true;
+}
+
+/*!
+ *  @brief  Provides the sensor_t data for this sensor
+ *  @param  sensor
+ */
+void DHT_Unified::Temperature::getSensor(sensor_t *sensor) {
+  // Clear sensor definition.
+  memset(sensor, 0, sizeof(sensor_t));
+  // Set sensor name.
+  _parent->setName(sensor);
+  // Set version and ID
+  sensor->version = DHT_SENSOR_VERSION;
+  sensor->sensor_id = _id;
+  // Set type and characteristics.
+  sensor->type = SENSOR_TYPE_AMBIENT_TEMPERATURE;
+  _parent->setMinDelay(sensor);
+  switch (_parent->_type) {
+  case DHT11:
+    sensor->max_value = 50.0F;
+    sensor->min_value = 0.0F;
+    sensor->resolution = 2.0F;
+    break;
+  case DHT12:
+    sensor->max_value = 60.0F;
+    sensor->min_value = -20.0F;
+    sensor->resolution = 0.5F;
+    break;
+  case DHT21:
+    sensor->max_value = 80.0F;
+    sensor->min_value = -40.0F;
+    sensor->resolution = 0.1F;
+    break;
+  case DHT22:
+    sensor->max_value = 125.0F;
+    sensor->min_value = -40.0F;
+    sensor->resolution = 0.1F;
+    break;
+  default:
+    // Unknown type, default to 0.
+    sensor->max_value = 0.0F;
+    sensor->min_value = 0.0F;
+    sensor->resolution = 0.0F;
+    break;
+  }
+}
+
+/*!
+ *  @brief  Instantiates a new DHT_Unified Humidity Class
+ *  @param  parent
+ *          Parent Sensor
+ *  @param  id
+ *          Sensor id
+ */
+DHT_Unified::Humidity::Humidity(DHT_Unified *parent, int32_t id)
+    : _parent(parent), _id(id) {}
+
+/*!
+ *  @brief  Reads the sensor and returns the data as a sensors_event_t
+ *  @param  event
+ *  @return always returns true
+ */
+bool DHT_Unified::Humidity::getEvent(sensors_event_t *event) {
+  // Clear event definition.
+  memset(event, 0, sizeof(sensors_event_t));
+  // Populate sensor reading values.
+  event->version = sizeof(sensors_event_t);
+  event->sensor_id = _id;
+  event->type = SENSOR_TYPE_RELATIVE_HUMIDITY;
+  event->timestamp = millis();
+  event->relative_humidity = _parent->_dht.readHumidity();
+
+  return true;
+}
+
+/*!
+ *  @brief  Provides the sensor_t data for this sensor
+ *  @param  sensor
+ */
+void DHT_Unified::Humidity::getSensor(sensor_t *sensor) {
+  // Clear sensor definition.
+  memset(sensor, 0, sizeof(sensor_t));
+  // Set sensor name.
+  _parent->setName(sensor);
+  // Set version and ID
+  sensor->version = DHT_SENSOR_VERSION;
+  sensor->sensor_id = _id;
+  // Set type and characteristics.
+  sensor->type = SENSOR_TYPE_RELATIVE_HUMIDITY;
+  _parent->setMinDelay(sensor);
+  switch (_parent->_type) {
+  case DHT11:
+    sensor->max_value = 80.0F;
+    sensor->min_value = 20.0F;
+    sensor->resolution = 5.0F;
+    break;
+  case DHT12:
+    sensor->max_value = 95.0F;
+    sensor->min_value = 20.0F;
+    sensor->resolution = 5.0F;
+    break;
+  case DHT21:
+    sensor->max_value = 100.0F;
+    sensor->min_value = 0.0F;
+    sensor->resolution = 0.1F;
+    break;
+  case DHT22:
+    sensor->max_value = 100.0F;
+    sensor->min_value = 0.0F;
+    sensor->resolution = 0.1F;
+    break;
+  default:
+    // Unknown type, default to 0.
+    sensor->max_value = 0.0F;
+    sensor->min_value = 0.0F;
+    sensor->resolution = 0.0F;
+    break;
+  }
+}

DHT_U.h

@@ -0,0 +1,101 @@
+/*!
+ *  @file DHT_U.h
+ *
+ *  DHT Temperature & Humidity Unified Sensor Library<Paste>
+ *
+ *  Adafruit invests time and resources providing this open source code,
+ *  please support Adafruit andopen-source hardware by purchasing products
+ *  from Adafruit!
+ *
+ *  Written by Tony DiCola (Adafruit Industries) 2014.
+ *
+ *  MIT license, all text above must be included in any redistribution
+ *
+ *  Permission is hereby granted, free of charge, to any person obtaining a copy
+ *  of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ *  furnished to do so, subject to the following conditions:
+ *
+ *  The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ *  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ *  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ *  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ *  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#ifndef DHT_U_H
+#define DHT_U_H
+
+#include <Adafruit_Sensor.h>
+#include <DHT.h>
+
+#define DHT_SENSOR_VERSION 1 /**< Sensor Version */
+
+/*!
+ *  @brief  Class that stores state and functions for interacting with
+ * DHT_Unified.
+ */
+class DHT_Unified {
+public:
+  DHT_Unified(uint8_t pin, uint8_t type, uint8_t count = 6,
+              int32_t tempSensorId = -1, int32_t humiditySensorId = -1);
+  void begin();
+
+  /*!
+   *  @brief  Class that stores state and functions about Temperature
+   */
+  class Temperature : public Adafruit_Sensor {
+  public:
+    Temperature(DHT_Unified *parent, int32_t id);
+    bool getEvent(sensors_event_t *event);
+    void getSensor(sensor_t *sensor);
+
+  private:
+    DHT_Unified *_parent;
+    int32_t _id;
+  };
+
+  /*!
+   *  @brief  Class that stores state and functions about Humidity
+   */
+  class Humidity : public Adafruit_Sensor {
+  public:
+    Humidity(DHT_Unified *parent, int32_t id);
+    bool getEvent(sensors_event_t *event);
+    void getSensor(sensor_t *sensor);
+
+  private:
+    DHT_Unified *_parent;
+    int32_t _id;
+  };
+
+  /*!
+   *  @brief  Returns temperature stored in _temp
+   *  @return Temperature value
+   */
+  Temperature temperature() { return _temp; }
+
+  /*!
+   *  @brief  Returns humidity stored in _humidity
+   *  @return Humidity value
+   */
+  Humidity humidity() { return _humidity; }
+
+private:
+  DHT _dht;
+  uint8_t _type;
+  Temperature _temp;
+  Humidity _humidity;
+
+  void setName(sensor_t *sensor);
+  void setMinDelay(sensor_t *sensor);
+};
+
+#endif

README.md

@@ -0,0 +1,58 @@
+# DHT sensor library [![Build Status](https://github.com/adafruit/DHT-sensor-library/workflows/Arduino%20Library%20CI/badge.svg)](https://github.com/adafruit/DHT-sensor-library/actions)
+
+## Description
+
+An Arduino library for the DHT series of low-cost temperature/humidity sensors.
+
+You can find DHT tutorials [here](https://learn.adafruit.com/dht).
+
+# Dependencies
+ * [Adafruit Unified Sensor Driver](https://github.com/adafruit/Adafruit_Sensor)
+
+# Contributing
+
+Contributions are welcome!  Not only you’ll encourage the development of the library, but you’ll also learn how to best use the library and probably some C++ too
+
+Please read our [Code of Conduct](https://github.com/adafruit/DHT-sensor-library/blob/master/CODE_OF_CONDUCT.md>)
+before contributing to help this project stay welcoming.
+
+## Documentation and doxygen
+Documentation is produced by doxygen. Contributions should include documentation for any new code added.
+
+Some examples of how to use doxygen can be found in these guide pages:
+
+https://learn.adafruit.com/the-well-automated-arduino-library/doxygen
+
+https://learn.adafruit.com/the-well-automated-arduino-library/doxygen-tips
+
+Written by Adafruit Industries based on work by:
+
+ * T. DiCola
+ * P. Y. Dragon
+ * L. Fried
+ * J. Hoffmann
+ * M. Kooijman
+ * J. M. Dana
+ * S. Conaway
+ * S. IJskes
+ * T. Forbes
+ * B. C
+ * T. J Myers
+ * L. Sørup
+ * per1234
+ * O. Duffy
+ * matthiasdanner
+ * J. Lim
+ * G. Ambrozio
+ * chelmi
+ * adams13x13
+ * Spacefish
+ * I. Scheller
+ * C. Miller
+ * 7eggert
+
+
+MIT license, check license.txt for more information
+All text above must be included in any redistribution
+
+To install, use the Arduino Library Manager and search for "DHT sensor library" and install the library.

README.txt

@@ -1,3 +0,0 @@
-This is an Arduino library for the DHT series of low cost temperature/humidity sensors. 
-
-To download. click the DOWNLOADS button in the top right corner, rename the uncompressed folder DHT. Check that the DHT folder contains DHT.cpp and DHT.h. Place the DHT library folder your <arduinosketchfolder>/libraries/ folder. You may need to create the libraries subfolder if its your first library. Restart the IDE.

code-of-conduct.md

@@ -0,0 +1,127 @@
+# Adafruit Community Code of Conduct
+
+## Our Pledge
+
+In the interest of fostering an open and welcoming environment, we as
+contributors and leaders pledge to making participation in our project and
+our community a harassment-free experience for everyone, regardless of age, body
+size, disability, ethnicity, gender identity and expression, level or type of
+experience, education, socio-economic status, nationality, personal appearance,
+race, religion, or sexual identity and orientation.
+
+## Our Standards
+
+We are committed to providing a friendly, safe and welcoming environment for
+all.
+
+Examples of behavior that contributes to creating a positive environment
+include:
+
+* Be kind and courteous to others
+* Using welcoming and inclusive language
+* Being respectful of differing viewpoints and experiences
+* Collaborating with other community members
+* Gracefully accepting constructive criticism
+* Focusing on what is best for the community
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+
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+
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+  asked
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+* Other conduct which could reasonably be considered inappropriate
+
+The goal of the standards and moderation guidelines outlined here is to build
+and maintain a respectful community. We ask that you don’t just aim to be
+"technically unimpeachable", but rather try to be your best self. 
+
+We value many things beyond technical expertise, including collaboration and
+supporting others within our community. Providing a positive experience for
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+providing the correct answer.
+
+## Our Responsibilities
+
+Project leaders are responsible for clarifying the standards of acceptable
+behavior and are expected to take appropriate and fair corrective action in
+response to any instances of unacceptable behavior.
+
+Project leaders have the right and responsibility to remove, edit, or
+reject messages, comments, commits, code, issues, and other contributions
+that are not aligned to this Code of Conduct, or to ban temporarily or
+permanently any community member for other behaviors that they deem
+inappropriate, threatening, offensive, or harmful.
+
+## Moderation
+
+Instances of behaviors that violate the Adafruit Community Code of Conduct
+may be reported by any member of the community. Community members are
+encouraged to report these situations, including situations they witness
+involving other community members.
+
+You may report in the following ways:
+
+In any situation, you may send an email to <support@adafruit.com>.
+
+On the Adafruit Discord, you may send an open message from any channel
+to all Community Helpers by tagging @community helpers. You may also send an
+open message from any channel, or a direct message to @kattni#1507,
+@tannewt#4653, @Dan Halbert#1614, @cater#2442, @sommersoft#0222, or
+@Andon#8175.
+
+Email and direct message reports will be kept confidential.
+
+In situations on Discord where the issue is particularly egregious, possibly
+illegal, requires immediate action, or violates the Discord terms of service,
+you should also report the message directly to Discord.
+
+These are the steps for upholding our community’s standards of conduct.
+
+1. Any member of the community may report any situation that violates the
+Adafruit Community Code of Conduct. All reports will be reviewed and
+investigated.
+2. If the behavior is an egregious violation, the community member who
+committed the violation may be banned immediately, without warning.
+3. Otherwise, moderators will first respond to such behavior with a warning.
+4. Moderators follow a soft "three strikes" policy - the community member may
+be given another chance, if they are receptive to the warning and change their
+behavior.
+5. If the community member is unreceptive or unreasonable when warned by a
+moderator, or the warning goes unheeded, they may be banned for a first or
+second offense. Repeated offenses will result in the community member being
+banned.
+
+## Scope
+
+This Code of Conduct and the enforcement policies listed above apply to all
+Adafruit Community venues. This includes but is not limited to any community
+spaces (both public and private), the entire Adafruit Discord server, and
+Adafruit GitHub repositories. Examples of Adafruit Community spaces include
+but are not limited to meet-ups, audio chats on the Adafruit Discord, or
+interaction at a conference.
+
+This Code of Conduct applies both within project spaces and in public spaces
+when an individual is representing the project or its community. As a community
+member, you are representing our community, and are expected to behave
+accordingly.
+
+## Attribution
+
+This Code of Conduct is adapted from the [Contributor Covenant][homepage],
+version 1.4, available at
+<https://www.contributor-covenant.org/version/1/4/code-of-conduct.html>,
+and the [Rust Code of Conduct](https://www.rust-lang.org/en-US/conduct.html).
+
+For other projects adopting the Adafruit Community Code of
+Conduct, please contact the maintainers of those projects for enforcement.
+If you wish to use this code of conduct for your own project, consider
+explicitly mentioning your moderation policy or making a copy with your
+own moderation policy so as to avoid confusion.

examples/DHT_Unified_Sensor/DHT_Unified_Sensor.ino

@@ -0,0 +1,85 @@
+// DHT Temperature & Humidity Sensor
+// Unified Sensor Library Example
+// Written by Tony DiCola for Adafruit Industries
+// Released under an MIT license.
+
+// REQUIRES the following Arduino libraries:
+// - DHT Sensor Library: https://github.com/adafruit/DHT-sensor-library
+// - Adafruit Unified Sensor Lib: https://github.com/adafruit/Adafruit_Sensor
+
+#include <Adafruit_Sensor.h>
+#include <DHT.h>
+#include <DHT_U.h>
+
+#define DHTPIN 2     // Digital pin connected to the DHT sensor 
+// Feather HUZZAH ESP8266 note: use pins 3, 4, 5, 12, 13 or 14 --
+// Pin 15 can work but DHT must be disconnected during program upload.
+
+// Uncomment the type of sensor in use:
+//#define DHTTYPE    DHT11     // DHT 11
+#define DHTTYPE    DHT22     // DHT 22 (AM2302)
+//#define DHTTYPE    DHT21     // DHT 21 (AM2301)
+
+// See guide for details on sensor wiring and usage:
+//   https://learn.adafruit.com/dht/overview
+
+DHT_Unified dht(DHTPIN, DHTTYPE);
+
+uint32_t delayMS;
+
+void setup() {
+  Serial.begin(9600);
+  // Initialize device.
+  dht.begin();
+  Serial.println(F("DHTxx Unified Sensor Example"));
+  // Print temperature sensor details.
+  sensor_t sensor;
+  dht.temperature().getSensor(&sensor);
+  Serial.println(F("------------------------------------"));
+  Serial.println(F("Temperature Sensor"));
+  Serial.print  (F("Sensor Type: ")); Serial.println(sensor.name);
+  Serial.print  (F("Driver Ver:  ")); Serial.println(sensor.version);
+  Serial.print  (F("Unique ID:   ")); Serial.println(sensor.sensor_id);
+  Serial.print  (F("Max Value:   ")); Serial.print(sensor.max_value); Serial.println(F("°C"));
+  Serial.print  (F("Min Value:   ")); Serial.print(sensor.min_value); Serial.println(F("°C"));
+  Serial.print  (F("Resolution:  ")); Serial.print(sensor.resolution); Serial.println(F("°C"));
+  Serial.println(F("------------------------------------"));
+  // Print humidity sensor details.
+  dht.humidity().getSensor(&sensor);
+  Serial.println(F("Humidity Sensor"));
+  Serial.print  (F("Sensor Type: ")); Serial.println(sensor.name);
+  Serial.print  (F("Driver Ver:  ")); Serial.println(sensor.version);
+  Serial.print  (F("Unique ID:   ")); Serial.println(sensor.sensor_id);
+  Serial.print  (F("Max Value:   ")); Serial.print(sensor.max_value); Serial.println(F("%"));
+  Serial.print  (F("Min Value:   ")); Serial.print(sensor.min_value); Serial.println(F("%"));
+  Serial.print  (F("Resolution:  ")); Serial.print(sensor.resolution); Serial.println(F("%"));
+  Serial.println(F("------------------------------------"));
+  // Set delay between sensor readings based on sensor details.
+  delayMS = sensor.min_delay / 1000;
+}
+
+void loop() {
+  // Delay between measurements.
+  delay(delayMS);
+  // Get temperature event and print its value.
+  sensors_event_t event;
+  dht.temperature().getEvent(&event);
+  if (isnan(event.temperature)) {
+    Serial.println(F("Error reading temperature!"));
+  }
+  else {
+    Serial.print(F("Temperature: "));
+    Serial.print(event.temperature);
+    Serial.println(F("°C"));
+  }
+  // Get humidity event and print its value.
+  dht.humidity().getEvent(&event);
+  if (isnan(event.relative_humidity)) {
+    Serial.println(F("Error reading humidity!"));
+  }
+  else {
+    Serial.print(F("Humidity: "));
+    Serial.print(event.relative_humidity);
+    Serial.println(F("%"));
+  }
+}

examples/DHTtester/DHTtester.ino

@@ -1,20 +1,27 @@
 // Example testing sketch for various DHT humidity/temperature sensors
 // Written by ladyada, public domain
 
+// REQUIRES the following Arduino libraries:
+// - DHT Sensor Library: https://github.com/adafruit/DHT-sensor-library
+// - Adafruit Unified Sensor Lib: https://github.com/adafruit/Adafruit_Sensor
+
 #include "DHT.h"
 
-#define DHTPIN 2     // what pin we're connected to
+#define DHTPIN 2     // Digital pin connected to the DHT sensor
+// Feather HUZZAH ESP8266 note: use pins 3, 4, 5, 12, 13 or 14 --
+// Pin 15 can work but DHT must be disconnected during program upload.
 
 // Uncomment whatever type you're using!
 //#define DHTTYPE DHT11   // DHT 11
-#define DHTTYPE DHT22   // DHT 22  (AM2302)
+#define DHTTYPE DHT22   // DHT 22  (AM2302), AM2321
 //#define DHTTYPE DHT21   // DHT 21 (AM2301)
 
 // Connect pin 1 (on the left) of the sensor to +5V
 // NOTE: If using a board with 3.3V logic like an Arduino Due connect pin 1
 // to 3.3V instead of 5V!
 // Connect pin 2 of the sensor to whatever your DHTPIN is
-// Connect pin 4 (on the right) of the sensor to GROUND
+// Connect pin 3 (on the right) of the sensor to GROUND (if your sensor has 3 pins)
+// Connect pin 4 (on the right) of the sensor to GROUND and leave the pin 3 EMPTY (if your sensor has 4 pins)
 // Connect a 10K resistor from pin 2 (data) to pin 1 (power) of the sensor
 
 // Initialize DHT sensor.
@@ -25,7 +32,7 @@ DHT dht(DHTPIN, DHTTYPE);
 
 void setup() {
   Serial.begin(9600);
-  Serial.println("DHTxx test!");
+  Serial.println(F("DHTxx test!"));
 
   dht.begin();
 }
@@ -44,7 +51,7 @@ void loop() {
 
   // Check if any reads failed and exit early (to try again).
   if (isnan(h) || isnan(t) || isnan(f)) {
-    Serial.println("Failed to read from DHT sensor!");
+    Serial.println(F("Failed to read from DHT sensor!"));
     return;
   }
 
@@ -53,17 +60,15 @@ void loop() {
   // Compute heat index in Celsius (isFahreheit = false)
   float hic = dht.computeHeatIndex(t, h, false);
 
-  Serial.print("Humidity: ");
+  Serial.print(F("Humidity: "));
   Serial.print(h);
-  Serial.print(" %\t");
-  Serial.print("Temperature: ");
+  Serial.print(F("%  Temperature: "));
   Serial.print(t);
-  Serial.print(" *C ");
+  Serial.print(F("°C "));
   Serial.print(f);
-  Serial.print(" *F\t");
-  Serial.print("Heat index: ");
+  Serial.print(F("°F  Heat index: "));
   Serial.print(hic);
-  Serial.print(" *C ");
+  Serial.print(F("°C "));
   Serial.print(hif);
-  Serial.println(" *F");
+  Serial.println(F("°F"));
 }

keywords.txt

@@ -12,11 +12,11 @@ DHT	KEYWORD1
 # Methods and Functions (KEYWORD2)
 ###########################################
 
-begin KEYWORD2
-readTemperature KEYWORD2
-convertCtoF KEYWORD2
-convertFtoC KEYWORD2
-computeHeatIndex KEYWORD2
-readHumidity KEYWORD2
-read KEYWORD2
+begin	KEYWORD2
+readTemperature	KEYWORD2
+convertCtoF	KEYWORD2
+convertFtoC	KEYWORD2
+computeHeatIndex	KEYWORD2
+readHumidity	KEYWORD2
+read	KEYWORD2
 

library.properties

@@ -1,5 +1,5 @@
 name=DHT sensor library
-version=1.2.2
+version=1.4.4
 author=Adafruit
 maintainer=Adafruit <info@adafruit.com>
 sentence=Arduino library for DHT11, DHT22, etc Temp & Humidity Sensors
@@ -7,3 +7,4 @@ paragraph=Arduino library for DHT11, DHT22, etc Temp & Humidity Sensors
 category=Sensors
 url=https://github.com/adafruit/DHT-sensor-library
 architectures=*
+depends=Adafruit Unified Sensor

license.txt

@@ -0,0 +1,20 @@
+Copyright (c) 2020 Adafruit Industries
+
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE
+OR OTHER DEALINGS IN THE SOFTWARE.