=Paper=
{{Paper
|id=Vol-3309/paper27
|storemode=property
|title=The climate control system using ESP8266 and Arduino IoT Cloud
|pdfUrl=https://ceur-ws.org/Vol-3309/paper27.pdf
|volume=Vol-3309
|authors=Serhii Tsyrulnyk,Maksym Tsyrulnyk,Nadiia Potapova,Andriy Semenov,Volodymyr Tromsyuk
|dblpUrl=https://dblp.org/rec/conf/ittap/TsyrulnykTPST22
}}
==The climate control system using ESP8266 and Arduino IoT Cloud==
https://ceur-ws.org/Vol-3309/paper27.pdf
The climate control system using ESP8266 and Arduino IoT Cloud
Serhii Tsyrulnyka,b, Maksym Tsyrulnykc, Nadiia Potapovac, Andriy Semenovd and Volodymyr
Tromsyuka
a
Vinnytsia Technical Applied College, Khmelnytske highway, 91/2, Vinnytsia, 21021, Ukraine
b
Vinnytsia National Agrarian University, str. Sonyachna, 3, City, Vinnytsia, 21008, Ukraine
c
Vasyl' Stus Donetsk National University, str. 600-richchia, 21, Vinnytsia, 21021, Ukraine
d
Vinnytsia National Technical University, Khmelnytske highway, 95, Vinnytsia, 21021, Ukraine
Abstract
Humidity in the air and temperature have a long-term and destructive effect on people,
machines, and materials. This paper proposes a system designed for remote control and
monitoring of the temperature and humidity of the premises of an educational institution.
To increase the accuracy of temperature and humidity measurement, the method of
weighted moving average is used. Such a system allows you to determine the dew point or
thermodynamic parameters of the air to control ventilation, heating, air conditioning in the
room, during working and non-working hours, as well as to control emergencies.
This technique uses a wireless control module with an ESP8266 microcontroller using a
Wi-Fi channel, which is integrated into the Internet of Things system. The microcontroller
allows you to measure temperature and humidity, send the measured value via a Wi-Fi
network to the IoT cloud, and perform remote control of the load, which is connected to
the 220 V power grid through a relay module. The free cloud service Arduino IoT Cloud
allows you to collect, analyze and manage data from a mobile application IoT Remote and
web dashboard. The proposed system can be improved and integrated into the centralized
climate control system of the educational institution, which in turn will allow the efficient
use of financial resources.
Keywords 1
Climate control, remote control, data monitoring, cloud service, module IoT, temperature
and humidity sensor, dewpoint, method of weighted moving average
1. Introduction
The Internet of Things (IoT) is an engineering solution in which electronic devices are combined
into a single integrated system and the Internet is used as a communication channel between them. IoT
platforms are used by suppliers and manufacturers of smart devices to equip their products with
functions of remote control, real-time monitoring, setting up alerts and notifications, and integration
with smartphones and other devices.
Temperature and humidity are critical parameters for many modern industries because of their long-
term and destructive effects on materials, equipment, and people.
Special requirements for temperature and air humidity are relevant for the storage of medical and
food products. Control of storage temperature and air humidity is important for various technological
processes.
ITTAP’2022: 2nd International Workshop on Information Technologies: Theoretical and Applied Problems, November 22–24, 2022,
Ternopil, Ukraine
EMAIL: sovm@ukr.net (S. Tsyrulnyk); maximtsyrulnyk@gmail.com (M. Tsyrulnyk); potapova.nadin@gmail.com (N. Potapova);
semenov79@ukr.net (A. Semenov); 2013tvd@gmail.com (V. Tromsyuk)
ORCID: 0000-0002-5703-9761 (S. Tsyrulnyk); 0000-0003-4566-4102 (N. Potapova); 0000-0001-9580-6602 (A. Semenov); 0000-0001-
5022-8159 (V. Tromsyuk)
©️ 2021 Copyright for this paper by its authors.
Use permitted under Creative Commons License Attribution 4.0 International (CC BY 4.0).
CEUR Workshop Proceedings (CEUR-WS.org)
Air temperature and humidity are of particular importance for the transportation of fresh and frozen
products; greenhouses for growing plants, incubators, and premises for keeping animals.
A violation of the conditions of production, storage, and transportation of products leads to
significant financial losses, and in the case of medical drugs - poses a threat to people's health and lives.
IoT-based temperature and humidity monitoring effectively reduce the cost of human resources for
temperature and humidity control.
One of the important tasks is to monitor the temperature and humidity of the environment without
restricting the movement of the user.
To ensure comfortable working conditions in the cold period, a system is needed that would allow
assessing the state of temperature, and humidity in premises for archival storage of documents,
educational institutions, pharmacies, museums, libraries, offices, and warehouse premises. This will
make it possible to effectively use financial resources and, upon the improvement of this system, to
automatically set the temperature on the premises, during working or non-working hours, and monitor
the state of emergency.
The main problem for the premises is the high relative humidity of the air and, as a result, the
condensation of moisture vapor on cold surfaces, which causes corrosion, rotting of materials, and the
formation of fungal mold.
The dew point is the temperature at which condensation occurs. The dew point temperature is
determined by the temperature and relative humidity of the air. The approximate calculation of the dew
point Tr (°C) depending on the air temperature T (°C) and its relative humidity Rh (%) is :
𝑎𝑇 (1)
𝑏( + ln(𝑅ℎ))
𝑇𝑟 = 𝑏 + 𝑇 ,
𝑎𝑇
𝑎−( + ln(𝑅ℎ))
𝑏+𝑇
where a =17.27, b =237.7.
During the development and operation of automated ventilation and air conditioning systems,
thermodynamic analysis of air processing is carried out based on the values of the main thermodynamic
parameters - heat and moisture content of moist air. The coordination of external and internal parameters
in rooms with ventilation can be ensured by changing the heat and moisture content of the air [1]. Of
the known methods, heat content can be most accurately determined by temperature and relative
humidity.
2. System Architecture
The climate monitoring system is a software-hardware module for wireless control using a Wi-Fi
channel, which is integrated into the Internet of Things system [2, 3] and allows you to measure the
temperature and humidity in the room and transmit the measured values via the Wi-Fi network with
remote access from a cell phone, tablet, or personal computer and performs remote control of an
electrical appliance (air conditioner or heater) in manual or automatic control mode depending on the
given cooling/heating algorithm.
DHT
o
IoT Cloud t, C
h, %
D8 relay
module
ESP8266
MCU
D4 ~220В
Figure 1: Structural diagram of the climate monitoring system
To exclude the influence of ambient temperature on the results of measuring relative humidity, it is
recommended to use humidity sensors together with temperature sensors [1], for example, DHT11,
DHT22, SHT11, SHT20, SHT30, BME280, GY-21, AM2320.
The climate monitoring system consists of a temperature and humidity sensor DHT11 [4], a control
unit with Wi-Fi network support (ESP8266 microcontroller) [5-7], an executive device - relay module,
power supply unit (Figure 1). Appointment indicators: supply voltage - 220 V ±10%; switched load
power 2500 W (10 A/250 V); the determination of temperature 0–60 °C with an accuracy of 2%;
determination of humidity 20%-90% with an accuracy of 2%; support for Wi-Fi networks of the 802.11
b/g/n standards.
2.1. Hardware
The main element of the IoT-based monitoring and control system, which receives information from
the DHT11 sensor and transmits it via Wi-Fi to a cloud service that the user can join and view
temperature and humidity information and remotely control devices that can affect climatic conditions
of the control object: heating or cooling, humidification or drying of the air.
Due to the ease of programming and ease of integration into various embedded systems, Arduino
boards are among the most common for electronic projects. The first generation of Arduino boards were
general-purpose microcontrollers that connected to the Internet using GSM and Wi-Fi modules, but as
the concept of the Internet of Things began to develop, boards with special functions supporting the
Internet of Things began to be developed: Arduino 101, Arduino MKR1000, Arduino Yun, Arduino
NANO 33 IoT and others.
Chips and boards based on the ESP8266 have become one of the best chipsets for Wi-Fi-based IoT
devices. These modules are quite cheap, consume little electricity, and are easy to use. Following the
ESP8266 module, Espressif offers the ESP32 module, which is based on a dual-core microcontroller
and has a wider set of functionality compared to the ESP8266 module. ESP chips have great flexibility
and can be used as Wi-Fi modules, connected to other microcontrollers, or used in stand-alone modes
without the use of additional microcontrollers. They have small form factors and simplify the
implementation of functions necessary for the IoT sphere, such as, for example, firmware updates "over
the air" (OTA technology - over-the-air). The availability of development boards such as NodeMCU
and other ESP-based third-party boards allows developers to familiarize themselves with the
capabilities of this platform before using it in projects. The ESP8266 boards come to FCC and CE
certified to reduce overall device certification costs after manufacturing. ESP boards provide one of the
most reliable, dedicated Wi-Fi interfaces that include several protocols that support the Internet of
Things, such as the ESP Touch protocol.
ESP8266 boards are fairly easy to learn and can be used with any microcontroller to create IoT
projects.
The port allocation of the WeMos D1 mini-module is shown in Figure 2. This module contains 11
general-purpose ports. Some ports have additional functions: GPIO1, GPIO3 – UART, GPIO5/D1,
GPIO4/D2 – I²C/TWI, D5..D8 – SPI, D1..D7 – outputs with PWM (PWM), A0 – analog output from
ADC. A temperature and humidity sensor is connected to the module through D8 (GPIO15).
To connect this module, it is sufficient to supply +5V supply voltage.
Figure 2: A pinout diagram of a module WeMos D1 mini and their corresponding functions
The key component of the monitoring system is the combined temperature and humidity sensor
DHT11 (DHT22, HDC1080, or BME280). The DHT11 sensor is a digital temperature and humidity
sensor. It consists of a capacitive humidity sensor and a thermistor. Also, the sensor contains an ADC
for converting analog values of humidity and temperature. DHT11 outputs a calibrated digital signal. It
uses exclusive digital signal acquisition and moisture sensing technology, ensuring its reliability and
stability.
The sensor connection diagram of the ESP8266 microcontroller is shown in Figure 3.
Figure 3: Connecting the DHT11 sensor to the ESP8266 microcontroller
Sensor data consist of integral and decimal parts for both relative humidity (RH) and temperature.
The data from the DHT11 sensor consists of 40 bits, and the format is as follows: 16 bits of humidity
data (high and low), 16 bits of temperature data (high and low), and 8 bits of checksum data (Figure 4).
Figure 4: DHT11 sensor data format
To check the accuracy of the obtained data, it is necessary to add all the values of humidity and
temperature and check whether the sum is equal to the value of the control sum:
00100101 + 00000000 + 00011001 + 00000000 = 00111110
To initialize data transmission, the host device (microcontroller) must send a start signal by setting
a low logic level on the data bus (SDA), with a duration of 0.8 . . . 20 ms. After sending the start signal,
the microcontroller must release the data bus (resetting the GPIO line to input) and proceed to poll its
status. In response to the start signal, the sensor sequentially sets low and high logic levels on the data
bus, each that is 80 us in duration. Next, the sensor outputs 5 information bytes (40 bits) containing
humidity and temperature data. Bytes are transmitted standardly, most significant bit first. First, the
higher byte of humidity (Humidity high) is transmitted, then the lower byte of humidity (Humidity low),
then the higher (Temperature high) and lower (Temperature low) bytes of temperature, and the last byte
contains the checksum (Parity bit). In this way, humidity and temperature are represented by two bytes,
for conversion, you must divide these numbers by 10. For example, if you received a two-byte number
638, divide it by 10, and you obtain the required value of 63.8.
The minimum interval for reading data from the sensor should be 2 seconds, with frequent access
the measurement error increases. The maximum cable length is 30 m at a supply voltage of 5 V, and at
a voltage of 3.3 V, the cable length should not exceed 1 m.
A Pull-up resistor must connect to the sensor (Figure 3). The sensor was always in sleep mode when
the line was high. To communicate with it, we must activate it, get confirmation and accept 40 bits of
data.
It is necessary to consider how to connect the executive device to the ESP8266 module. To control
external devices, the same MK input/output ports that work for output are used. Signals from any line
of any port can easily be used to turn on and off an external device. It is only necessary to amplify the
control signal by the power to the required level. Various coordination schemes are used for this
purpose. The choice of the scheme depends on the type of executive device. In the simplest case, you
can use a transistor key. To control links with a large current, you must use a more powerful transistor
or a complete transistor assembly. When selecting a transistor, we consider that the maximum
permissible load current for any MK output should not exceed 20 mas. If the GPIO2 port (Figure 5) is
set to a single level, the switch opens and the load is connected to the power source. At a zero level at
the same output, the switch is closed, and the load is disconnected.
Figure 5: An executive device using a relay
If the executive device to be controlled by the ESP8266 is powered by 220 V AC, a galvanically
isolated control scheme must be used. One of the possible options is a relay control scheme. A typical
version of the control circuit using a relay is shown in Figure 5. The circuit shows an electronic key,
the load of which includes the electromagnetic relay K1. The ESP8266 module can turn the
electromagnetic relay on and off using a key. Relay contacts, in turn, control the load. Such a scheme
provides switching of a sufficiently large voltage and current.
The galvanic separation between all circuits and the 220 V power network ensures the safety of
working with this scheme. Diode VD1 is designed to protect the elements of the circuit from the voltage
of self-induction that occurs in coil K1 at the moment of closing the switch VT1. When choosing an
electromagnetic relay, one should pay attention to the following parameters. The first is the voltage of
the relay. For the device under development, it should be equal to 5 V. Second, the maximum allowable
switching current and the maximum allowable voltage should be for the executive contacts of the relay.
They must correspond to the actual values of the current and voltage in the load circuit. We chose the
relay type SRD-05VDC-SL-C.
Figure 6: The circuit of the climate monitoring system using ESP8266
AC-DC voltage converter Hi-Link HLK-PM01 with an output voltage of 5 V and a maximum output
current of 0.6 A is used to power the climate monitoring system with a voltage of +5 V from the mains
voltage. The block has a small-sized hermetic case with legs for mounting on a printed circuit board.
There is built-in short circuit protection.
When building many measuring devices, the problem arises of reducing random errors during
measurement. Increasing the accuracy of measurements is achieved by reducing random measurement
errors using the weighted moving average method with a digital recursive filter, which is implemented
by software [8].
2.2. Software
2.2.1. Arduino IoT Cloud
An IoT platforms are used by suppliers and manufacturers of smart devices to equip their products
with functions of remote control, real-time monitoring, setting up alerts and notifications, and
integration with smartphones and other devices.
IoT platforms provide seamless integration of different hardware using communication protocols,
applying different types of topology (direct connection or gateway). The IoT platform is a key tool for
developing IoT applications and services, which combine physical objects (things) and the network
(Internet).
The most popular software IoT platforms are Microsoft Azure IoT, Amazon Web Services (AWS)
IoT, Google Cloud, ThingWorx IoT, IBM Watson, Artik from Samsung Electronics, Cisco IoT Cloud
Connect, Salesforce IoT Cloud, ThingSpeak, and many others [2, 3, 6, 7]. Among the protocols used
by IoT platforms, the most popular are MQTT, CoAP, HTTP/HTTPS, AMQP, XMPP, and DDS [5].
Arduino IoT Cloud data storage greatly simplifies data storage and provides a full range of services
within the concept of the Internet of Things (IoT). It includes hardware and software, cloud services,
and a knowledge base. This cloud-based data warehouse allows users to collect, analyze and graph data
from sensors, event handlers, and more. The Arduino IoT Cloud platform allows users to write the
codes of their programs, compile and download them to boards directly from the browser, connect IoT
devices, and use a virtual dashboard in real-time. The Arduino IoT Cloud platform automatically
generates a sketch according to the settings specified by the user when the device is connected to the
cloud. Arduino IoT Cloud can be integrated with Amazon Alexa, Google Sheets, IFTTT, and ZAPIER
allowing users to program and control devices using voice, spreadsheets, databases, and automate
notifications using webhooks. The platform also allows developers to build their applications using the
Arduino IoT API, adding custom webhooks to the endpoints for greater flexibility.
When using Arduino IoT Cloud for free, one can add only two devices to the platform and the
compilation time is limited to 200 seconds per day. To expand the possibility of using the platform, you
can choose one of the paid tariffs, for example, ENTRY ($2.99/month), which allows you to create 10
Things, unlimited compilation time, and unlimited storage for sketches [9].
To work with Arduino IoT Cloud [10, 12], you must create and log into an account and add a new
device to it, namely, the NodeMCU ESP8266. To do this, go to the "Devices" tab and click "Add device"
(Figure 7).
Figure 7: Adding a new device to the project
Figure 8 shows the hardware platform selection window. We press "Set up a 3rd party device" and
select the development board we use. To do this, first select ESP8266 as the device type, and then select
NodeMCU1.0 from the drop-down menu.
Figure 8: NodeMCU ESP8266 board selection tab
Figure 9: NodeMCU ESP8266 board selection tab
Next, set the name of the device and click Next (Figure 9). A window will appear with the device
ID (Device ID) and the secret key (Secret Key) for this device. Device ID and Secret Key must be saved
in notepad or click on “download the PDF” to save them in PDF format.
The next step is to create a subject/thing. To do this, go to the “Things” tab and click on “Create”
(Figure 10).
Figure 10: Things creation tab
On the Things tab (Figure 11), three options need to be configured: Variables, Device, and Network.
Figure 11: Adding project variables
To add variables that will be used in the program code, press the "Add variable" button. After that,
a window will open in which you must fill in the information about the variables (Figure 12). In this
project, we will use three variables, one of which will be used to control the relay, and the other two
will be used to store the temperature and humidity values.
Figure 12: Setting project variables
First, let's create a relay switch (led). Its data type will be Boolean (bool), its value can only be read
(Read-only), and the update option (update policy) will be enabled for it. After that, click the "Add
variable" button. Similarly, we add a variable for storing temperature and humidity values. The data
type for these variables float, they can be read (Read-only), and the updated option for them will also
be enabled. Let's associate devices with things. To do this, click the link icon in the "Device" section.
After that, a window will open in which the previously created device will be available for selection. In
the next step, you must enter data to access the Wi-Fi network (its name and password) and the secret
key that was issued during the installation of the device. To do this, click the Configure button in the
Network section and enter the necessary information (Figure 13).
Figure 13: Setting up data to connect to Arduino IoT Cloud
The next step is to create a dashboard. To do this, go to the Dashboard tab and click on Create
(Figure 14).
Figure 14: Creating a project dashboard
To add widgets to the dashboard, click on the pencil icon in the upper left corner, then click the
“Add” button. We go to the “Widgets” tab and add the “Switch”, “Percentage Gauge”, and “Chart”
widgets, which we associate with the led, humidity, and temperature variables (Figure 15). In the upper
right corner of each widget, there is a context menu with the “Edit setting” command, which allows
binding to variables, a range of values, and an initial value. Therefore, Figure 16 shows the settings of
the properties of the “Chart” temperature change diagram.
Figure 15: Project dashboard settings
Figure 16: Chart widget settings
The software consists of a program for the ESP8266 microcontroller and provides for its interaction
with mobile service or online service. When choosing, you must decide what functionality the user
wants to get: the Wi-Fi module is an access point and data can be obtained only by establishing a
connection with the module via a wireless channel; the module is connected to a Wi-Fi network and
transmits data to a mobile application and/or to the cloud, which will allow separate control and
monitoring of data; temperature and humidity information is private or shareable; data monitoring only
from mobile devices and/or personal computers; how often to receive data; need to keep the data and
for how long.
2.2.2. IoT module software
After configuring the Arduino IoT Cloud platform, it is necessary to program the NodeMCU
ESP8266 board to read data from the DHT11 sensor, transmit it to the cloud, and perform remote control
functions.
When adding variables to “Things”, the sketch in the cloud is automatically updated. Most of the
application code (sketch) is automatically generated by the platform. It is necessary to add lines to work
with the DHT11 sensor and implement the remote control algorithm. To do this, open the Arduino
Cloud Editor code editor on the Sketch tab (Figure 17).
Figure 17: Editing the sketch code automatically generated by the Arduino IoT Cloud platform
The DHT.h library is used to work with the DHT11 sensor [4]. The DHT.h library has built-in
functions readTemperature(), readHumidity() for reading temperature and humidity values. The
command is used to connect the library
#include "DHT.h"
#include
We create an object of the DHT class dht (DHTPIN, DHTTYPE). In the first parameter, we specify
the port number where the sensor is connected, in the second, we specify the sensor type.
#define DHTPIN 15
#define DHTTYPE DHT11
DHT dht(DHTPIN, DHTTYPE);
In the setup function, we determine the speed of data exchange between the computer and ESP8266
through the virtual serial port, configure the GPIO2 port as an output for controlling the relay module,
and start the DHT sensor. Next, we initialize the variables that were created in Arduino IoT Cloud
(thingProperties.h), connected to the cloud via the Wi-Fi network (network connection parameters
SSID, PASS, KEY are stored in the file Secret.h).
void setup() {
Serial.begin(9600);
pinMode(2, OUTPUT);
delay(1500);
dht.begin();
initProperties();
ArduinoCloud.begin(ArduinoIoTPreferredConnection);
setDebugMessageLevel(2);
ArduinoCloud.printDebugInfo();
}
In the loop function, we call the ArduinoCloud.update() function to update data in the Arduino IoT
Cloud and the DHT_SENSOR_READ() function, which reads the temperature and humidity values from
the sensor and outputs these data to the port monitor (to monitor the sensor's performance).
void loop() {
ArduinoCloud.update();
DHT_SENSOR_READ();
}
The remote control mechanism is implemented in the onLedChange() function. Depending on the
state of the variable “led” (Switch widget), the relay module that controls ventilation, heating, air
conditioning is turned on or off.
void onLedChange(){
if (led==1)
digitalWrite (2, HIGH);
else
digitalWrite (2, LOW);
}
The DHT_SENSOR_READ() function reads temperature and humidity values from the DHT11
combined sensor and calls the AutoControl() function, which performs automatic control mode
depending on the given cooling/heating algorithm.
void DHT_SENSOR_READ(){
float K_Filter = 3.0;
float h, t, h_previous, h_current, t_previous, t_current;
float dewpoint;
h = dht.readHumidity();
h_previous = h_current;
h_current = h_previous + (h - h_previous)/ K_Filter;
t = dht.readTemperature();
t_previous = t_current;
t_current = t_previous + (t - t_previous)/ K_Filter;
temperature = t_current;
humidity = h_current;
dewpoint = dewPoint();AutoControl();
Serial.print("Temperature - "); Serial.println(t);
Serial.print("Humidity - "); Serial.println(h);
delay(1000);
}
The dewPoint () function determines the value of the dew point by the values of temperature and
humidity, the accuracy of which is increased by the weighted moving average method.
float dewPoint(){
float a=17.27, float b=237.7;
float funRhT = a* temperature/(b+ temperature);
funRhT += log(humidity/100);
float drew = b*funRhT/(a-funRhT);
return drew;
}
The AutoControl () function implements algorithms for regulating automated ventilation and air
conditioning systems based on the value of the dew point or basic thermodynamic parameters [13]. The
code of this function can be adapted to any task of climate control according to the rules of fuzzy logic
[14] and add automatic notifications using webhooks through the IFTTT service, for example, sending
notifications to the Telegram channel or email.
void AutoContro(){
if ((temperature > 22) || (humidity >65))
digitalWrite (2, HIGH);
else
digitalWrite (2, LOW);
delay (1500);
}
2.2.3 Programming an ESP8266 to transfer data to the Arduino cloud
Let's add the DHT.h library to the Arduino Cloud Editor. To do this, select Libraries in the vertical
menu and enter DHT in the search query window. Among the proposed libraries, select DHT SENSOR
LIBRARY FOR ESPX (Figure 18). We physically connected the NodeMCU module with the
connected DHT11 sensor (Figure 6) and the LED simulating the operation of the relay (installed on the
module by the manufacturer) to the computer. If the Arduino IoT Cloud does not automatically detect
the connected module, you must install the Arduino Create Agent program. Figure 19 shows that the
NodeMCU module is connected to COM9 and you can start verifying the project. If there are no errors,
select the “Load” button and download the sketch to the NodeMCU module.
Figure 18: Adding the DHT library in the Arduino Cloud Editor
Figure 19: Checking code for errors in Arduino IoT Cloud
Open the “Serial Monitor” mode (Figure 20) and observe the temperature and humidity data
measured by the sensor and transmitted by the module to the computer through the virtual serial port.
Figure 20: Output of NodeMCU module information to Arduino IoT Cloud in “Serial Monitor” mode
3. Results
The climate monitoring system is based on the ESP8266 microcontroller, which is part of the
NodeMCU or WeMos D1 mini platform. The microcontroller organizes data transfer via Wi-Fi to the
Arduino IoT Cloud platform. A DHT11 sensor was used as a combined temperature and humidity
sensor. The GPIO2 port is used to control the executive device in manual or automatic control mode,
depending on the given cooling/heating algorithm. The experimental sample is implemented on the
NodeMCU module, as an indication of the remote control mode, a blue LED built into the board is
used, which is connected by the cathode to the GPIO2 port (Figure 21). This must be considered because
some relay modules (Figure 6) use a p-n-p type transistor (switched on by a logic 0 level).
Figure 21: An experimental sample of the climate control system based on the NodeMCU module
The online monitoring and control panel that was created on the Arduino IoT Cloud platform is
shown in Figure 22. For the convenience of working with the Arduino IoT Cloud dashboard, you can
install the IoT Remote mobile application on your phone from the official Google Play or App Store
(Figure 22).
Figure 22: The dashboard of the climate monitoring system using Arduino IoT Cloud
During experimental research, the proposed system made it possible to apply the weighted moving
average method to increase the accuracy of temperature and humidity measurements. At a temperature
of 26.8 °C and a humidity of 65%, the calculated value of the dew point is 19.65 °C, which corresponds
to the reference table values.
4. Conclusion
Control of storage temperature and air humidity is important for various technological processes.
The use of wireless technologies provides some advantages: ease of installation and operation,
scalability and simplicity of the solution, and integration of mobile devices. Wireless technology is an
attractive choice for the renovation, repair, and installation of new systems. IoT-based temperature and
humidity monitoring effectively reduce the cost of human resources for temperature and humidity
control.
Arduino Cloud IoT allows the user to collect, analyze and manage data from a mobile application
and web dashboard.
The article proposes to apply the weighted moving average method to increase the accuracy of
measuring temperature and humidity parameters, which are used to calculate the value of the dew point
or thermodynamic air parameters, which are necessary for the algorithms of automated ventilation and
air conditioning systems.
The climate control system is implemented based on the IoT module NodeMCU (WeMos), the
combined sensor DHT11, and the relay module with minimal cost and the possibility of adaptation to
the monitoring and control system of the premises of the educational institution. Current climate data
are available online. The operator, who directly controls the site, sees all the information in real-time
on a digital panel. This, in turn, allows for efficient use of financial resources and, upon the
improvement of this system, to automatically set the temperature on the premises, during working or
non-working hours, and monitor the state of emergency.
5. References
[1] V. Vychuzhanyn, S. Maliuta, Digital device for determining the thermodynamic parameters of air
on the FPGA company Altera, Circuit design, 4, 2005, pp. 30-33.
[2] S. Tsyrulnyk, Mobile applications and online WI-FI monitoring platforms of weather stations,
Open educational e-environment of modern University, volume 9, 2020, pp. 181–192. doi:
10.28925/2414-0325.2020.9.15.
[3] S. Tsyrulnyk, M. Tsyrulnyk, Temperature and humidity monitoring system on the IOT module, in:
Proceedings of the II NPK. Computer Technologies of Data Processing (CTDP-2021), Vinnytsia,
2021, pp. 105-108. URL: https://jktod.donnu.edu.ua/article/view/11664/11539.
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