💬 Air Humidity Sensor - DHT

[flopp]

@hek
All other examples are using PIN 3. Wouldn't it be easier to use PIN 3 for all examples? Maybe we shall wait and see if mozzbozz know why he changed to PIN 2.

[hek]

Ok, updated the example on github and instructions on the page back to pin 3.

[skywatch]

Hurrah! :)

Now I can sleep at night again ;)

Good job!

[hek]

@skywatch said:

Now I can sleep at night again

Haha, yeah, good to hear you will get a good nights sleep again.

[flopp]

@skywatch said:

Hurrah! :)

Now I can sleep at night again ;)

Good job!

haha, me too :)

[Pavel Larkin]

Hello. Maybe someone could help :) hopefully..
I have arduino1 with 1 DHT22, which is over arduinoGW connected to RSPi with latest domoticz.
when i connect stuff up, after some time i see some strange childids, not related to this arduino1 in no way.
Lots of unknown!, with V_TEMP values, with V_HUM values, even V_FORECAST, V_PRESSURE and etc. which arduino1 should not send (or no other arduino on my area).

Illustration:
<img href="http://www.lstudio.lt/wp-content/uploads/dht22problem.png">
http://www.lstudio.lt/wp-content/uploads/dht22problem.png

my code is quite simple (for ex only temperature is shown)

#define CHILD_DESCR "TEMP3"
#undef CHILD_ID
#define CHILD_ID 31
present(CHILD_ID, S_TEMP, CHILD_DESCR);
delay(250) ;

loop:

  temp3=dht3.readTemperature();

if (temp3 >= 120) {temp3 = lasttemp3;}
if (temp3 <= -50) {temp3 = lasttemp3;}
MyMessage msg31(CHILD_ID,V_TEMP);
send(msg31.set(temp3,1));

so.. that is basically all

[flopp]

@Pavel-Larkin

I have also seen this, I noticed it last week. Some of my Nodes have those Unknown-child, but it is working correctly anyway.
DZ 3.5877, MyS 1.5.1, RPi 2

[Gimlur]

Hello,
i have a problem with this sketch.
After downloading DTH.h froom Mysensors Examples, i have this error :
DhtTemperatureAndHumiditySensor:85: error: 'getConfig' was not declared in this scope

metric = getConfig().isMetric;

Any Idea of my mistake ?...

[hek]

It isn't your mistake, it's ours. The examples hasn't been updated correctly to reflect the most recent change in the api.

It should say getControllerConfig().isMetric

[johnecy]

I have the dht22 sensor hooked up and working on a pro mini on pin 3 I get a normal temp reading but the humidity always stays at 1.0 does not read.

[mfalkvidd]

@johnecy https://forum.mysensors.org/topic/5978/temperature-and-humidity-dht22

[donhuan78p]

Hello everybody,
hope, someone could help a newby :-)
I've installed the MQTT - GW and would use the Air/Humidity - sensor. But it doesn't work properly.
The Connection to the Gateway seems to be okay. But I get no Air/Humidity - Information.
The sensor does not measure anything.
I've tried to change the data - pin, I've tried the DHT11 and DHT22 - sensor. No choice.
I'm getting mad :-)

Thanks a lot.

[gohan]

Have you tried the basic arduino sketch that prints data to serial port?

[donhuan78p]

Hello,
thanks a lot for your answer.
Yes, I did. It produced the Messages as excepted.

[gohan]

So you'd better post your code so we can take a look at what is wrong with it.

[donhuan78p]

...sorry, Typo.
As expected :-)

[donhuan78p]

...no Problem:

/**
 * 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_NRF24
//#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 2

// Set this offset if the sensor has a permanent small offset to the real temperatures
#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 = 30000;

// 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
  Serial.println("Presentation");
  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 = getConfig().isMetric;
}


void setup()
{
  Serial.println("vor Presentation");
  
  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()      
{  

  Serial.println("loop Anfang");
  
  // 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;
    if (!metric) {
      temperature = dht.toFahrenheit(temperature);
    }
    // Reset no updates counter
    nNoUpdatesTemp = 0;
    temperature += SENSOR_TEMP_OFFSET;
    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); 
}

[Arnold Šlepetis]

I am using dht22 outside. Does any one know how to change to whole number not decimal. The temperature outside change a lot. Let say temp 20.2 changed to 20.4 and still sends to getaway . If I do "send(msgTemp.set(temperature, 0));" and still receive both times 20 and 20, and I want only if change to 21 or 19.

[mfalkvidd]

@Arnold-Šlepetis change

float lastTemp;

to

signed int lastTemp;

and

float temperature = dht.getTemperature();

to

signed int temperature = dht.getTemperature() + 0.5; // Add 0.5 to get correct rounding

and

temperature = dht.toFahrenheit(temperature);

to

temperature = dht.toFahrenheit(temperature) + 0.5;

and

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

to

send(msgTemp.set(temperature));

You might also have to handle the isnan test.

[Arnold Šlepetis]

@mfalkvidd Thanks. It works like a charm