Датчик влажности воздуха

Часто используемый датчик влажности и температуры это DHT, бывает в двух вариантах с разной степенью точности.

	DHT-11	DHT-22
Диапазон влажности	20%-80%RH (±5%RH)	0%-100%RH (±2%RH)
Время измерения	1 сек за выборку	2 сек за выборку

Есть и другие датчики влажности, которые требуют меньше энергии для работы, такие как BME280 или Si7021. См. Это сравнение чтобы получить больше информации о их точности.

Подключение

Датчик	Arduino	Комментарий
—	GND	Чёрный
+	VCC (3.3 — 5.5V)	Красный
Out (средний)	Цифровой вывод 3	Зелёный

Пример

В этом примере используется модифицированная версия библиотеки DTH, которая включена в примеры MySensors. Пожалуйста, установите его и перезапустите среду разработки Arduino перед компиляцией.

/**
 * The MySensors Arduino library handles the wireless radio link and protocol
 * between your home built sensors/actuators and HA controller of choice.
 * The sensors forms a self healing radio network with optional repeaters. Each
 * repeater and gateway builds a routing tables in EEPROM which keeps track of the
 * network topology allowing messages to be routed to nodes.
 *
 * Created by Henrik Ekblad <henrik.ekblad@mysensors.org>
 * Copyright (C) 2013-2015 Sensnology AB
 * Full contributor list: https://github.com/mysensors/Arduino/graphs/contributors
 *
 * Documentation: http://www.mysensors.org
 * Support Forum: http://forum.mysensors.org
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * version 2 as published by the Free Software Foundation.
 *
 *******************************
 *
 * REVISION HISTORY
 * Version 1.0: Henrik EKblad
 * Version 1.1 - 2016-07-20: Converted to MySensors v2.0 and added various improvements - Torben Woltjen (mozzbozz)
 * 
 * DESCRIPTION
 * This sketch provides an example of how to implement a humidity/temperature
 * sensor using a DHT11/DHT-22.
 *  
 * For more information, please visit:
 * http://www.mysensors.org/build/humidity
 * 
 */

// Enable debug prints
#define MY_DEBUG

// Enable and select radio type attached 
#define MY_RADIO_RF24
//#define MY_RADIO_RFM69
//#define MY_RS485
 
#include <SPI.h>
#include <MySensors.h>  
#include <DHT.h>

// Set this to the pin you connected the DHT's data pin to
#define DHT_DATA_PIN 3

// Set this offset if the sensor has a permanent small offset to the real temperatures.
// In Celsius degrees (as measured by the device)
#define SENSOR_TEMP_OFFSET 0

// Sleep time between sensor updates (in milliseconds)
// Must be >1000ms for DHT22 and >2000ms for DHT11
static const uint64_t UPDATE_INTERVAL = 60000;

// Force sending an update of the temperature after n sensor reads, so a controller showing the
// timestamp of the last update doesn't show something like 3 hours in the unlikely case, that
// the value didn't change since;
// i.e. the sensor would force sending an update every UPDATE_INTERVAL*FORCE_UPDATE_N_READS [ms]
static const uint8_t FORCE_UPDATE_N_READS = 10;

#define CHILD_ID_HUM 0
#define CHILD_ID_TEMP 1

float lastTemp;
float lastHum;
uint8_t nNoUpdatesTemp;
uint8_t nNoUpdatesHum;
bool metric = true;

MyMessage msgHum(CHILD_ID_HUM, V_HUM);
MyMessage msgTemp(CHILD_ID_TEMP, V_TEMP);
DHT dht;


void presentation()  
{ 
  // Send the sketch version information to the gateway
  sendSketchInfo("TemperatureAndHumidity", "1.1");
  
  // Register all sensors to gw (they will be created as child devices)
  present(CHILD_ID_HUM, S_HUM);
  present(CHILD_ID_TEMP, S_TEMP);
  
  metric = getControllerConfig().isMetric;
}


void setup()
{
  dht.setup(DHT_DATA_PIN); // set data pin of DHT sensor
  if (UPDATE_INTERVAL <= dht.getMinimumSamplingPeriod()) {
    Serial.println("Warning: UPDATE_INTERVAL is smaller than supported by the sensor!");
  }
  // Sleep for the time of the minimum sampling period to give the sensor time to power up
  // (otherwise, timeout errors might occure for the first reading)
  sleep(dht.getMinimumSamplingPeriod());
}


void loop()      
{  
  // Force reading sensor, so it works also after sleep()
  dht.readSensor(true);
  
  // Get temperature from DHT library
  float temperature = dht.getTemperature();
  if (isnan(temperature)) {
    Serial.println("Failed reading temperature from DHT!");
  } else if (temperature != lastTemp || nNoUpdatesTemp == FORCE_UPDATE_N_READS) {
    // Only send temperature if it changed since the last measurement or if we didn't send an update for n times
    lastTemp = temperature;

    // apply the offset before converting to something different than Celsius degrees
    temperature += SENSOR_TEMP_OFFSET;

    if (!metric) {
      temperature = dht.toFahrenheit(temperature);
    }
    // Reset no updates counter
    nNoUpdatesTemp = 0;
    send(msgTemp.set(temperature, 1));

    #ifdef MY_DEBUG
    Serial.print("T: ");
    Serial.println(temperature);
    #endif
  } else {
    // Increase no update counter if the temperature stayed the same
    nNoUpdatesTemp++;
  }

  // Get humidity from DHT library
  float humidity = dht.getHumidity();
  if (isnan(humidity)) {
    Serial.println("Failed reading humidity from DHT");
  } else if (humidity != lastHum || nNoUpdatesHum == FORCE_UPDATE_N_READS) {
    // Only send humidity if it changed since the last measurement or if we didn't send an update for n times
    lastHum = humidity;
    // Reset no updates counter
    nNoUpdatesHum = 0;
    send(msgHum.set(humidity, 1));
    
    #ifdef MY_DEBUG
    Serial.print("H: ");
    Serial.println(humidity);
    #endif
  } else {
    // Increase no update counter if the humidity stayed the same
    nNoUpdatesHum++;
  }

  // Sleep for a while to save energy
  sleep(UPDATE_INTERVAL); 
}

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/**

* The MySensors Arduino library handles the wireless radio link and protocol

* between your home built sensors/actuators and HA controller of choice.

* The sensors forms a self healing radio network with optional repeaters. Each

* repeater and gateway builds a routing tables in EEPROM which keeps track of the

* network topology allowing messages to be routed to nodes.

* Created by Henrik Ekblad <henrik.ekblad@mysensors.org>

* Full contributor list: https://github.com/mysensors/Arduino/graphs/contributors

* Documentation: http://www.mysensors.org

* Support Forum: http://forum.mysensors.org

* This program is free software; you can redistribute it and/or

* modify it under the terms of the GNU General Public License

* version 2 as published by the Free Software Foundation.

*******************************

* REVISION HISTORY

* Version 1.0: Henrik EKblad

* Version 1.1 - 2016-07-20: Converted to MySensors v2.0 and added various improvements - Torben Woltjen (mozzbozz)

* DESCRIPTION

* This sketch provides an example of how to implement a humidity/temperature

* sensor using a DHT11/DHT-22.

* For more information, please visit:

* http://www.mysensors.org/build/humidity

// Enable debug prints

#define MY_DEBUG

// Enable and select radio type attached

#define MY_RADIO_RF24

//#define MY_RADIO_RFM69

//#define MY_RS485

#include <SPI.h>

#include <MySensors.h>

#include <DHT.h>

// Set this to the pin you connected the DHT's data pin to

#define DHT_DATA_PIN 3

// Set this offset if the sensor has a permanent small offset to the real temperatures.

// In Celsius degrees (as measured by the device)

#define SENSOR_TEMP_OFFSET 0

// Sleep time between sensor updates (in milliseconds)

// Must be >1000ms for DHT22 and >2000ms for DHT11

static const uint64_t UPDATE_INTERVAL = 60000;

// Force sending an update of the temperature after n sensor reads, so a controller showing the

// timestamp of the last update doesn't show something like 3 hours in the unlikely case, that

// the value didn't change since;

// i.e. the sensor would force sending an update every UPDATE_INTERVAL*FORCE_UPDATE_N_READS [ms]

static const uint8_t FORCE_UPDATE_N_READS = 10;

#define CHILD_ID_HUM 0

#define CHILD_ID_TEMP 1

float lastTemp;

float lastHum;

uint8_t nNoUpdatesTemp;

uint8_t nNoUpdatesHum;

bool metric = true;

MyMessage msgHum(CHILD_ID_HUM, V_HUM);

MyMessage msgTemp(CHILD_ID_TEMP, V_TEMP);

DHT dht;

void presentation()

{

// Send the sketch version information to the gateway

sendSketchInfo("TemperatureAndHumidity", "1.1");

// Register all sensors to gw (they will be created as child devices)

present(CHILD_ID_HUM, S_HUM);

present(CHILD_ID_TEMP, S_TEMP);

metric = getControllerConfig().isMetric;

}

void setup()

{

dht.setup(DHT_DATA_PIN); // set data pin of DHT sensor

if (UPDATE_INTERVAL <= dht.getMinimumSamplingPeriod()) {

Serial.println("Warning: UPDATE_INTERVAL is smaller than supported by the sensor!");

}

// Sleep for the time of the minimum sampling period to give the sensor time to power up

// (otherwise, timeout errors might occure for the first reading)

sleep(dht.getMinimumSamplingPeriod());

}

void loop()

{

// Force reading sensor, so it works also after sleep()

dht.readSensor(true);

// Get temperature from DHT library

float temperature = dht.getTemperature();

if (isnan(temperature)) {

Serial.println("Failed reading temperature from DHT!");

} else if (temperature != lastTemp || nNoUpdatesTemp == FORCE_UPDATE_N_READS) {

// Only send temperature if it changed since the last measurement or if we didn't send an update for n times

lastTemp = temperature;

// apply the offset before converting to something different than Celsius degrees

temperature += SENSOR_TEMP_OFFSET;

if (!metric) {

temperature = dht.toFahrenheit(temperature);

}

// Reset no updates counter

nNoUpdatesTemp = 0;

send(msgTemp.set(temperature, 1));

#ifdef MY_DEBUG

Serial.print("T: ");

Serial.println(temperature);

#endif

} else {

// Increase no update counter if the temperature stayed the same

nNoUpdatesTemp++;

}

// Get humidity from DHT library

float humidity = dht.getHumidity();

if (isnan(humidity)) {

Serial.println("Failed reading humidity from DHT");

} else if (humidity != lastHum || nNoUpdatesHum == FORCE_UPDATE_N_READS) {

// Only send humidity if it changed since the last measurement or if we didn't send an update for n times

lastHum = humidity;

// Reset no updates counter

nNoUpdatesHum = 0;

send(msgHum.set(humidity, 1));

#ifdef MY_DEBUG

Serial.print("H: ");

Serial.println(humidity);

#endif

} else {

// Increase no update counter if the humidity stayed the same

nNoUpdatesHum++;

}

// Sleep for a while to save energy

sleep(UPDATE_INTERVAL);

}

Документация

DHT11.pdf

DHT22.pdf