Adding DHT22 library

lib/esp32DHT/.gitignore

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+.pioenvs
+.vscode
+lib
+.vscode/.browse.c_cpp.db*
+.vscode/c_cpp_properties.json
+.vscode/launch.json
+platformio.ini
+.piolibdeps

lib/esp32DHT/.travis.yml

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+language: python
+python:
+    - "2.7"
+
+# Cache PlatformIO packages using Travis CI container-based infrastructure
+sudo: false
+cache:
+    directories:
+        - "~/.platformio"
+
+env:
+    - PLATFORMIO_CI_SRC=examples/DHT22/DHT22.ino
+    - CPPLINT=true
+
+install:
+    - pip install -U platformio
+    - pip install -U cpplint
+
+script:
+    - if [[ "$CPPLINT" ]]; then cpplint --repository=. --recursive --linelength=200 --filter=-build/include ./src; else platformio ci --lib="." --board=lolin32; fi
+
+notifications:
+  email:
+    on_success: change
+    on_failure: change

lib/esp32DHT/LICENSE

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+MIT License
+
+Copyright (c) 2018 Bert Melis
+
+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.

lib/esp32DHT/README.md

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+# esp32DHT
+
+[![Build Status](https://travis-ci.com/bertmelis/esp32DHT.svg?branch=master)](https://travis-ci.com/bertmelis/esp32DHT)
+
+This is a DHT11/22 library for ESP32 using the RMT peripheral, for use in the Arduino framework.  
+For ESP8266, please look into this repo: [DHT](https://github.com/bertmelis/DHT)
+
+The library is non blocking, doesn't use delay and is usable in async frameworks. The library is kept simple on purpose. You are responsible yourself to follow the sensor's constraints (like polling frequency) and logical programming errors. Supplementary functions like dew point calculation are not included.
+
+## Installation
+
+* For Arduino IDE: see [the Arduino Guide](https://www.arduino.cc/en/Guide/Libraries#toc4)
+* For Platformio: see the [Platfomio guide](http://docs.platformio.org/en/latest/projectconf/section_env_library.html)
+
+## Usage
+
+```C++
+#include <Arduino.h>
+#include <esp32DHT.h>
+
+DHT22 sensor;
+
+void setup() {
+  Serial.begin(112500);
+  sensor.setup(23);
+  sensor.setCallback([](int8_t result) {
+    if (result > 0) {
+      Serial.printf("Temp: %.1f°C\nHumid: %.1f%%\n", sensor.getTemperature(), sensor.getHumidity());
+    } else {
+      Serial.printf("Sensor error: %s", sensor.getError());
+    }
+  });
+}
+
+void loop() {
+  static uint32_t lastMillis = 0;
+  if (millis() - lastMillis > 30000) {
+      lastMillis = millis();
+      sensor.read();
+      Serial.print("Read DHT...\n");
+  }
+}
+```
+
+> Note: `setup(uint8_t, rmt_channel_t channel = RMT_CHANNEL_0);` taks 2 arguments: the pin connected to the DHT sensor and the RMT channel[0-7]. The library uses 2 channels and defaults to (starting) channel 0. This means that by default channel 0 and channel 1 are occupied by the DHT and you should not use channel 7. If you're also using other RMT channels (for IR devices, extra DHT sensors, Neopixels...) you have to keep this in mind.
+>
+> Read more about RMT in the docs: [ESP-IDF documentation](https://esp-idf.readthedocs.io/en/latest/api-reference/peripherals/rmt.html)
+
+## History
+
+Whatever can be done using hardware should not be done by software. ESP32 has a RMT peripheral device which is remarkably versatile. As the DHT sensors rely on tight timing, the RMT device is perfect to accomplish reliable communication. I didn't find any other Arduino library that uses the RMT and/or doesn't block during communication. So I created my own one.
+
+> This library won't exist without the examples for RMT. Credits go to the team and contributors of ESP-IDF and @nkolban!

lib/esp32DHT/buildexamples.bat

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+platformio ci --lib="." --board=lolin32 examples/DHT22/DHT22.ino

lib/esp32DHT/examples/DHT22/DHT22.ino

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+/*
+
+Copyright 2018 Bert Melis
+
+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 <Arduino.h>
+#include <Ticker.h>
+#include <esp32DHT.h>
+
+Ticker ticker;
+DHT22 sensor;
+// DHT11 sensor;  // DHT11 also works!
+
+void readDHT() {
+  sensor.read();
+}
+
+void setup() {
+  Serial.begin(74880);
+  sensor.setup(23);  // pin 23 is DATA, RMT channel defaults to channel 0 and 1
+  sensor.onData([](float humidity, float temperature) {
+    Serial.printf("Temp: %g°C\nHumid: %g%%\n", temperature,humidity);
+  });
+  sensor.onError([](uint8_t error) {
+    Serial.printf("Sensor error: %s", sensor.getError());
+  });
+  ticker.attach(30, readDHT);
+}
+
+void loop() {
+}

lib/esp32DHT/keywords.txt

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+#######################################
+# Datatypes (KEYWORD1)
+#######################################
+
+DHT11	KEYWORD1
+DHT22	KEYWORD1
+
+#######################################
+# Methods and Functions (KEYWORD2)
+#######################################
+
+setPin	KEYWORD2
+setCallback	KEYWORD2
+read	KEYWORD2
+ready	KEYWORD2
+getTemperature	KEYWORD2
+getHumidity	KEYWORD2
+getError	KEYWORD2
+
+#######################################
+# Constants (LITERAL1)
+#######################################
+
+#yourLITERAL	LITERAL1

lib/esp32DHT/library.json

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+{
+  "name": "esp32DHT",
+  "version": "1.0.1",
+  "keywords": "DHT, DTH11, DHT22, RMT, callback, Arduino, ESP32",
+  "description": "DHT sensor library for ESP32 using the RMT peripheral",
+  "homepage": "https://github.com/bertmelis/esp32DHT",
+  "license": "MIT",
+  "authors": {
+    "name": "Bert Melis",
+    "url": "https://github.com/bertmelis",
+    "maintainer": true
+  },
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/bertmelis/esp32DHT.git",
+    "branch": "master"
+  },
+  "frameworks": "arduino",
+  "platforms": [
+    "espressif32"
+  ]
+}

lib/esp32DHT/library.properties

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+name=esp32DHT
+version=1.0.1
+author=Bert Melis
+maintainer=Bert Melis
+sentence=DHT sensor library for ESP32 using the RMT pheripheral
+paragraph=
+category=Sensors
+url=https://github.com/bertmelis/esp32DHT
+architectures=esp32

lib/esp32DHT/src/esp32DHT.cpp

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+/*
+
+Copyright 2018 Bert Melis
+
+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 CONDHTTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+*/
+
+#include "esp32DHT.hpp"  // NOLINT
+
+#define RMT_CLK_DIV 80
+
+DHT::DHT() :
+  _status(0),
+  _data{0},
+  _pin(0),
+  _channel(RMT_CHANNEL_0),
+  _onData(nullptr),
+  _onError(nullptr),
+  _timer(nullptr),
+  _task(nullptr) {}
+
+DHT::~DHT() {
+  if (_timer) {  // if _timer is true, setup() has been called
+                 // so RMT driver is loaded and the aux task is
+                 // running
+    esp_timer_delete(_timer);
+    rmt_driver_uninstall(_channel);
+    vTaskDelete(_task);
+  }
+}
+
+void DHT::setup(uint8_t pin, rmt_channel_t channel) {
+  _pin = pin;
+  _channel = channel;
+  esp_timer_create_args_t _timerConfig;
+  _timerConfig.arg = static_cast<void*>(this);
+  _timerConfig.callback = reinterpret_cast<esp_timer_cb_t>(_handleTimer);
+  _timerConfig.dispatch_method = ESP_TIMER_TASK;
+  _timerConfig.name = "esp32DHTTimer";
+  esp_timer_create(&_timerConfig, &_timer);
+  rmt_config_t config;
+  config.rmt_mode = RMT_MODE_RX;
+  config.channel = _channel;
+  config.gpio_num = static_cast<gpio_num_t>(_pin);
+  config.mem_block_num = 2;
+  config.rx_config.filter_en = 1;
+  config.rx_config.filter_ticks_thresh = 10;
+  config.rx_config.idle_threshold = 1000;
+  config.clk_div = RMT_CLK_DIV;
+  rmt_config(&config);
+  rmt_driver_install(_channel, 400, 0);  // 400 words for ringbuffer containing pulse trains from DHT
+  rmt_get_ringbuf_handle(_channel, &_ringBuf);
+  xTaskCreate((TaskFunction_t)&_handleData, "esp32DHT", 2048, this, 5, &_task);
+  pinMode(_pin, OUTPUT);
+  digitalWrite(_pin, HIGH);
+}
+
+void DHT::onData(esp32DHTInternals::OnData_CB callback) {
+  _onData = callback;
+}
+
+void DHT::onError(esp32DHTInternals::OnError_CB callback) {
+  _onError = callback;
+}
+
+void DHT::read() {
+  // _pin should be set to OUTPUT and HIGH
+  digitalWrite(_pin, LOW);
+  esp_timer_start_once(_timer, 18 * 1000);  // timer is in microseconds
+  _data[0] = _data[1] = _data[2] = _data[3] = _data[4] = 0;
+  _status = 0;
+}
+
+const char* DHT::getError() const {
+  if (_status == 0) {
+    return "OK";
+  } else if (_status == 1) {
+    return "TO";
+  } else if (_status == 2) {
+    return "NACK";
+  } else if (_status == 3) {
+    return "DATA";
+  } else if (_status == 4) {
+    return "CS";
+  } else if (_status == 5) {
+    return "UNDERFLOW";
+  } else if (_status == 6) {
+    return "OVERFLOW";
+  }
+  return "UNKNOWN";
+}
+
+void DHT::_handleTimer(DHT* instance) {
+  pinMode(instance->_pin, INPUT);
+  rmt_rx_start(instance->_channel, 1);
+  rmt_set_pin(instance->_channel, RMT_MODE_RX, static_cast<gpio_num_t>(instance->_pin));  // reset after using pin as output
+  xTaskNotifyGive(instance->_task);
+}
+
+void DHT::_handleData(DHT* instance) {
+  size_t rx_size = 0;
+  while (1) {
+    ulTaskNotifyTake(pdTRUE, portMAX_DELAY);  // block and wait for notification
+    // blocks until data is available or timeouts after 1000
+    rmt_item32_t* items = static_cast<rmt_item32_t*>(xRingbufferReceive(instance->_ringBuf, &rx_size, 1000));
+    if (items) {
+      instance->_decode(items, rx_size/sizeof(rmt_item32_t));
+      vRingbufferReturnItem(instance->_ringBuf, static_cast<void*>(items));
+      rmt_rx_stop(instance->_channel);
+      pinMode(instance->_pin, OUTPUT);
+      digitalWrite(instance->_pin, HIGH);
+    } else {
+      instance->_status = 1;  // timeout error
+      rmt_rx_stop(instance->_channel);
+      pinMode(instance->_pin, OUTPUT);
+      digitalWrite(instance->_pin, HIGH);
+    }
+    instance->_tryCallback();
+  }
+}
+
+void DHT::_decode(rmt_item32_t* data, int numItems) {
+  if (numItems < 42) {
+    _status = 5;
+  } else if (numItems > 42) {
+    _status = 6;
+  } else if ((data[0].duration0 + data[0].duration1) < 140 && (data[0].duration0 + data[0].duration1) > 180) {
+    _status = 2;
+  } else {
+    for (uint8_t i = 1; i < numItems - 1; ++i) {  // don't include tail
+      uint8_t pulse = data[i].duration0 + data[i].duration1;
+      if (pulse > 55 && pulse < 145) {
+        _data[(i - 1) / 8] <<= 1;  // shift left
+        if (pulse > 120) {
+          _data[(i - 1) / 8] |= 1;
+        }
+      } else {
+        _status = 3;  // DATA error
+        return;
+      }
+    }
+    if (_data[4] == ((_data[0] + _data[1] + _data[2] + _data[3]) & 0xFF)) {
+      _status = 0;
+    } else {
+      _status = 4;  // checksum error
+    }
+  }
+}
+
+void DHT::_tryCallback() {
+  if (_status == 0) {
+    if (_onData) _onData(_getHumidity(), _getTemperature());
+  } else {
+    if (_onError) _onError(_status);
+  }
+}
+
+float DHT11::_getTemperature() {
+  if (_status != 0) return NAN;
+  return static_cast<float>(_data[2]);
+}
+
+float DHT11::_getHumidity() {
+  if (_status != 0) return NAN;
+  return static_cast<float>(_data[0]);
+}
+
+float DHT22::_getTemperature() {
+  if (_status != 0) return NAN;
+  float temp = (((_data[2] & 0x7F) << 8) | _data[3]) * 0.1;
+  if (_data[2] & 0x80) {  // negative temperature
+    temp = -temp;
+  }
+  return temp;
+}
+
+float DHT22::_getHumidity() {
+  if (_status != 0) return NAN;
+  return ((_data[0] << 8) | _data[1]) * 0.1;
+}

lib/esp32DHT/src/esp32DHT.h

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+/*
+
+Copyright 2018 Bert Melis
+
+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.
+
+*/
+
+#pragma once
+
+#include "esp32DHT.hpp"

lib/esp32DHT/src/esp32DHT.hpp

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+/*
+
+Copyright 2018 Bert Melis
+
+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.
+
+*/
+
+#pragma once
+
+extern "C" {
+  #include <freertos/FreeRTOS.h>
+  #include <freertos/task.h>
+  #include <esp32-hal-gpio.h>
+  #include <driver/rmt.h>
+  #include <esp_timer.h>
+}
+#include <functional>
+
+namespace esp32DHTInternals {
+
+typedef std::function<void(float, float)> OnData_CB;
+typedef std::function<void(uint8_t)> OnError_CB;
+
+}  // end namespace esp32DHTInternals
+
+class DHT {
+ public:
+  DHT();
+  ~DHT();
+  void setup(uint8_t pin, rmt_channel_t channel = RMT_CHANNEL_0);  // setPin does complete setup of DHT lib
+  void onData(esp32DHTInternals::OnData_CB callback);
+  void onError(esp32DHTInternals::OnError_CB callback);
+  void read();
+  const char* getError() const;
+
+ protected:
+  uint8_t _status;
+  uint8_t _data[5];
+
+ private:
+  static void _handleTimer(DHT* instance);
+  static void _handleData(DHT* instance);
+  void _decode(rmt_item32_t* data, int numItems);
+  void _tryCallback();
+  virtual float _getTemperature() = 0;
+  virtual float _getHumidity() = 0;
+
+ private:
+  uint8_t _pin;
+  rmt_channel_t _channel;
+  esp32DHTInternals::OnData_CB _onData;
+  esp32DHTInternals::OnError_CB _onError;
+  esp_timer_handle_t _timer;
+  TaskHandle_t _task;
+  RingbufHandle_t _ringBuf;
+};
+
+class DHT11 : public DHT {
+ private:
+  float _getTemperature();
+  float _getHumidity();
+};
+
+class DHT22 : public DHT {
+ private:
+  float _getTemperature();
+  float _getHumidity();
+};