Update library.properties

Fix for slower boards. Use uint16_t in expectPulse loop to increase sampling rate

.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.

DHT.cpp

@@ -6,44 +6,53 @@ written by Adafruit Industries
 
 #include "DHT.h"
 
+#define MIN_INTERVAL 2000
+#define TIMEOUT -1
+
 DHT::DHT(uint8_t pin, uint8_t type, uint8_t count) {
   _pin = pin;
   _type = type;
-  _firstreading = true;
-  _bit = digitalPinToBitMask(pin);
-  _port = digitalPinToPort(pin);
+  #ifdef __AVR
+    _bit = digitalPinToBitMask(pin);
+    _port = digitalPinToPort(pin);
+  #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) {
   // set up the pins!
-  pinMode(_pin, INPUT);
-  digitalWrite(_pin, HIGH);
-  _lastreadtime = 0;
-  DEBUG_PRINT("Max clock cycles: "); DEBUG_PRINTLN(_maxcycles, DEC);
+  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 = millis() - MIN_INTERVAL;
+  DEBUG_PRINT("DHT max clock cycles: "); DEBUG_PRINTLN(_maxcycles, DEC);
 }
 
 //boolean S == Scale.  True == Fahrenheit; False == Celcius
-float DHT::readTemperature(bool S) {
+float DHT::readTemperature(bool S, bool force) {
   float f = NAN;
 
-  if (read()) {
+  if (read(force)) {
     switch (_type) {
     case DHT11:
+    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 /= 10;
+      f = ((word)(data[2] & 0x7F)) << 8 | data[3];
+      f *= 0.1;
       if (data[2] & 0x80) {
         f *= -1;
       }
@@ -57,26 +66,25 @@ float DHT::readTemperature(bool S) {
 }
 
 float DHT::convertCtoF(float c) {
-  return c * 9 / 5 + 32;
+  return c * 1.8 + 32;
 }
 
 float DHT::convertFtoC(float f) {
-  return (f - 32) * 5 / 9;
+  return (f - 32) * 0.55555;
 }
 
-float DHT::readHumidity(void) {
+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 /= 10;
+      f = ((word)data[0]) << 8 | data[1];
+      f *= 0.1;
       break;
     }
   }
@@ -84,24 +92,26 @@ float DHT::readHumidity(void) {
 }
 
 //boolean isFahrenheit: True == Fahrenheit; False == Celcius
-float DHT::computeHeatIndex(float temperature, float percentHumidity, bool isFahrenheit) {
-  // Adapted from equation at: https://github.com/adafruit/DHT-sensor-library/issues/9 and
-  // Wikipedia: http://en.wikipedia.org/wiki/Heat_index
-  if (!isFahrenheit) {
-    // Celsius heat index calculation.
-    return -8.784695 +
-             1.61139411 * temperature +
-             2.338549   * percentHumidity +
-            -0.14611605 * temperature*percentHumidity +
-            -0.01230809 * pow(temperature, 2) +
-            -0.01642482 * pow(percentHumidity, 2) +
-             0.00221173 * pow(temperature, 2) * percentHumidity +
-             0.00072546 * temperature*pow(percentHumidity, 2) +
-            -0.00000358 * pow(temperature, 2) * pow(percentHumidity, 2);
-  }
-  else {
-    // Fahrenheit heat index calculation.
-    return -42.379 +
+float DHT::computeHeatIndex(bool isFahrenheit) {
+  float hi = computeHeatIndex(readTemperature(isFahrenheit), readHumidity(),
+    isFahrenheit);
+  return isFahrenheit ? hi : convertFtoC(hi);
+}
+
+//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
+  float hi;
+
+  if (!isFahrenheit)
+    temperature = convertCtoF(temperature);
+
+  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 +
@@ -110,22 +120,25 @@ float DHT::computeHeatIndex(float temperature, float percentHumidity, bool isFah
              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);
+
+    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(void) {
+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 (currenttime < _lastreadtime) {
-    // ie there was a rollover
-    _lastreadtime = 0;
-  }
-  if (!_firstreading && ((currenttime - _lastreadtime) < 2000)) {
+  if (!force && ((currenttime - _lastreadtime) < MIN_INTERVAL)) {
     return _lastresult; // return last correct measurement
   }
-  _firstreading = false;
-  _lastreadtime = millis();
+  _lastreadtime = currenttime;
 
   // Reset 40 bits of received data to zero.
   data[0] = data[1] = data[2] = data[3] = data[4] = 0;
@@ -135,37 +148,44 @@ boolean DHT::read(void) {
 
   // 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);
 
     // Now start reading the data line to get the value from the DHT sensor.
-    pinMode(_pin, INPUT);
-    delayMicroseconds(10);  // Delay a bit to let sensor pull data line low.
+    delayMicroseconds(60);  // 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;
     }
@@ -189,8 +209,8 @@ boolean DHT::read(void) {
   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."));
+    if ((lowCycles == TIMEOUT) || (highCycles == TIMEOUT)) {
+      DEBUG_PRINTLN(F("DHT timeout waiting for pulse."));
       _lastresult = false;
       return _lastresult;
     }
@@ -205,7 +225,7 @@ boolean DHT::read(void) {
     // stored data.
   }
 
-  DEBUG_PRINTLN(F("Received:"));
+  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(", "));
@@ -219,7 +239,7 @@ boolean DHT::read(void) {
     return _lastresult;
   }
   else {
-    DEBUG_PRINTLN(F("Checksum failure!"));
+    DEBUG_PRINTLN(F("DHT checksum failure!"));
     _lastresult = false;
     return _lastresult;
   }
@@ -233,14 +253,18 @@ boolean DHT::read(void) {
 // 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) {
+#if (F_CPU > 16000000L)
   uint32_t count = 0;
+#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 0; // Exceeded timeout, fail.
+        return TIMEOUT; // Exceeded timeout, fail.
       }
     }
   // Otherwise fall back to using digitalRead (this seems to be necessary on ESP8266
@@ -248,7 +272,7 @@ uint32_t DHT::expectPulse(bool level) {
   #else
     while (digitalRead(_pin) == level) {
       if (count++ >= _maxcycles) {
-        return 0; // Exceeded timeout, fail.
+        return TIMEOUT; // Exceeded timeout, fail.
       }
     }
   #endif

DHT.h

@@ -30,6 +30,7 @@ written by Adafruit Industries
 
 // Define types of sensors.
 #define DHT11 11
+#define DHT12 12
 #define DHT22 22
 #define DHT21 21
 #define AM2301 21
@@ -39,18 +40,23 @@ class DHT {
   public:
    DHT(uint8_t pin, uint8_t type, uint8_t count=6);
    void begin(void);
-   float readTemperature(bool S=false);
+   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(void);
-   boolean read(void);
+   float readHumidity(bool force=false);
+   bool read(bool force=false);
 
  private:
-  uint8_t data[6];
-  uint8_t _pin, _type, _bit, _port;
+  uint8_t data[5];
+  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 _firstreading;
   bool _lastresult;
 
   uint32_t expectPulse(bool level);
@@ -60,10 +66,14 @@ class DHT {
 class InterruptLock {
   public:
    InterruptLock() {
+#if !defined(ARDUINO_ARCH_NRF52)  
     noInterrupts();
+#endif
    }
    ~InterruptLock() {
+#if !defined(ARDUINO_ARCH_NRF52)  
     interrupts();
+#endif
    }
 
 };

DHT_U.cpp

@@ -0,0 +1,195 @@
+// DHT Temperature & Humidity Unified Sensor Library
+// Copyright (c) 2014 Adafruit Industries
+// Author: Tony DiCola
+
+// 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.
+#include "DHT_U.h"
+
+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)
+{}
+
+void DHT_Unified::begin() {
+  _dht.begin();
+}
+
+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;
+}
+
+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;
+  }
+}
+
+DHT_Unified::Temperature::Temperature(DHT_Unified* parent, int32_t id):
+  _parent(parent),
+  _id(id)
+{}
+
+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;
+}
+
+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;
+  }
+}
+
+DHT_Unified::Humidity::Humidity(DHT_Unified* parent, int32_t id):
+  _parent(parent),
+  _id(id)
+{}
+
+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;
+}
+
+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 +1,78 @@
+// DHT Temperature & Humidity Unified Sensor Library
+// Copyright (c) 2014 Adafruit Industries
+// Author: Tony DiCola
+
+// 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
+
+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();
+
+  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;
+
+  };
+
+  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;
+
+  };
+
+  Temperature temperature() {
+    return _temp;
+  }
+
+  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 +1,15 @@
+This is an Arduino library for the DHT series of low cost temperature/humidity sensors.
+
+Tutorial: https://learn.adafruit.com/dht
+
+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.
+
+# Adafruit DHT Humidity & Temperature Unified Sensor Library
+
+This library also includes an optional class for the
+[DHT humidity and temperature sensor](https://learn.adafruit.com/dht/overview)
+which is designed to work with the [Adafruit unified sensor library](https://learn.adafruit.com/using-the-adafruit-unified-sensor-driver/introduction).
+
+You must have the following Arduino libraries installed to use this class:
+
+- [Adafruit Unified Sensor Library](https://github.com/adafruit/Adafruit_Sensor)

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.

examples/DHT_Unified_Sensor/DHT_Unified_Sensor.ino

@@ -0,0 +1,83 @@
+// DHT Temperature & Humidity Sensor
+// Unified Sensor Library Example
+// Written by Tony DiCola for Adafruit Industries
+// Released under an MIT license.
+
+// Depends on the following Arduino libraries:
+// - Adafruit Unified Sensor Library: https://github.com/adafruit/Adafruit_Sensor
+// - DHT Sensor Library: https://github.com/adafruit/DHT-sensor-library
+
+#include <Adafruit_Sensor.h>
+#include <DHT.h>
+#include <DHT_U.h>
+
+#define DHTPIN     2         // Pin connected to the DHT sensor.
+
+// 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

@@ -3,11 +3,11 @@
 
 #include "DHT.h"
 
-#define DHTPIN 2     // what pin we're connected to
+#define DHTPIN 2     // what digital pin we're connected to
 
 // 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
@@ -25,7 +25,7 @@ DHT dht(DHTPIN, DHTTYPE);
 
 void setup() {
   Serial.begin(9600);
-  Serial.println("DHTxx test!");
+  Serial.println(F("DHTxx test!"));
 
   dht.begin();
 }
@@ -44,7 +44,7 @@ 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 +53,15 @@ 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=1.1.1
+version=1.3.1
 author=Adafruit
 maintainer=Adafruit <info@adafruit.com>
 sentence=Arduino library for DHT11, DHT22, etc Temp & Humidity Sensors