The project involves the creation of one or more monitoring stations of the domestic environment which can possibly, with due care, be extended to public and / or corporate environments.

architettura del sistema di monitoraggio


The project was born from the idea of raising awareness on issues such as environmental comfort and how the latter affects personal health. During the last period of the pandemic we may have found ourselves locked in the house without being ready for it: from temporary workstations to poorly lit environments, the problems can be different.

There are several factors that contribute to environmental comfort and their optimization allows you to improve your health. I wrote several articles on this:

The project was also born as a reinforcement of the @ TCS project, reinforcing some design points but expanding from temperature / humidity to other factors.

Various topics are covered such as the importance of lighting, air quality, soundproofing and problems related to ergonomics in the workplace.

Everything is developed on an open source platform so that it can be easily replicated by anyone. It uses NodeMCU, designed for the IoT, which allows you to easily read different sensors and integrate with web systems. There is also a server where all the data is collected so that you can always have the history of the previous months and be able to estimate the necessary corrections.

All the software and hardware used is opensource and the entire project is based on the Arduino and NodeMCU development environment.

server monitoraggio
Webserver of the single monitoring device

The system will focus more on general control and integration with home automation currently on the market, also mentioning the possibility of setting basic controls with actuators.

Typical Tasmota configuration

The monitoring project

Within the project we want to show the importance of having a comfortable environment and how environmental well-being is fundamental for health within both the home and the workplace. Various factors are taken into consideration such as temperature and humidity, lighting, noise pollution and air quality, considering the presence of particulate matter and constant renewal.


NodeMCU is an open source platform developed specifically for the IoT. It includes a firmware that works through the ESP8266 wifi module and comes with several hardware bases. The ESP12E module was used in the following examples. The chip is easily programmable with Arduino IDE by integrating the necessary libraries.

Reading sensors

With this device you can easily control various digital sensors such as the DHT22 for temperature and humidity or the DS18B20 for temperature, even in immersion.

Trivially, to read the sensor it is sufficient to refer to the relative libraries, for example:

#include "DHT.h"
#define DHTTYPE DHT11
// Reading temperature or humidity takes about 250 milliseconds!
// Sensor readings may also be up to 2 seconds 'old' (its a very slow sensor)
float h = dht.readHumidity();
// Read temperature as Celsius (the default)
float t = dht.readTemperature();
linking schema for DHT11 + DS18B20
Real application – Prototype no. 6 – Used to read temperature and humidity in a domestic environment. Located inside an electrical box.

Web pages

You can easily connect to the internet either by using the device as an access point or by connecting to an existing network. Using the AsyncWebServer and AsyncTCP libraries, a web server is easily created in which sensor data can be integrated. For example, you create an HTLM page with containers for the data:

  <i class="fas fa-thermometer-half" style="color:#059e8a;"</i> 
  <span class="dht-labels">Temperature</span> 
  <span id="temperature">%TEMPERATURE%</span>
  <sup class="units">°C</sup>

Then we add a Javascript algorithm to automatically update the containers.

setInterval(function ( ) {
  var xhttp = new XMLHttpRequest();
  xhttp.onreadystatechange = function() {
    if (this.readyState == 4 && this.status == 200) {
      document.getElementById("temperature").innerHTML = this.responseText;
  };"GET", "/temperature", true);
}, 10000 ) ;

Clearly it is also necessary to use a function that is called for a chosen time interval so as to request data with the url / data:"GET", "/data", true);
}, 10000 ) ;
if (this.readyState == 4 && this.status == 200) {
  document.getElementById("temperature").innerHTML = this.responseText;

Then you pass the data to a function that takes care of updating the containers in the HTLM page

String processor(const String& var){
  if(var == "TEMPERATURE"){
    return String(t);
  else if(var == "DATA"){
    return String(data);
  return String();

For complete codes refer to the GitHub repository.

Dark Mode

tempcontrol (this link opens in a new window) by mastroalex (this link opens in a new window)

The purpose of this project is to create a station for monitoring the environmental conditions for home.

Alexa integration

The Sinric Pro platform was used to quickly integrate the system with Alexa. The code provided is used, setting the parameters and the device correctly. Then add the “SinricPro” skill on Alexa and after login you will be able to see the temperature sensor.

Mobile app SinricPro and Alexa


The repository contains both the procedure for building a database on Raspberry Pi that can be used in the LAN and the procedure for a remote host. The procedure is very similar. A MySQL table is created by associating a sensor to each column:

    sensor VARCHAR(30) NOT NULL,
    location VARCHAR(30) NOT NULL,
    value1 VARCHAR(10),
    value2 VARCHAR(10),
    value3 VARCHAR(10),

Then a .php page is created containing the code to write the data in the database received through a POST request from the ESP.

    $api_key = test_input($_POST["api_key"]);
    if($api_key == $api_key_value) {
        $sensor = test_input($_POST["sensor"]);
        $location = test_input($_POST["location"]);
        $value1 = test_input($_POST["value1"]);
        $value2 = test_input($_POST["value2"]);
        $value3 = test_input($_POST["value3"]);
        // Create connection
        $conn = new mysqli($servername, $username, $password, $dbname);
        // Check connection
        if ($conn->connect_error) {
            die("Connection failed: " . $conn->connect_error);
        $sql = "INSERT INTO SensorData (sensor, location, value1, value2, value3)
        VALUES ('" . $sensor . "', '" . $location . "', '" . $value1 . "', '" . $value2 . "', '" . $value3 . "')";
        if ($conn->query($sql) === TRUE) {
            echo "New record created successfully";
        else {
            echo "Error: " . $sql . "<br>" . $conn->error;

The ESP must be configured to make the POST request correctly by sending a message containing the chained sensor data in the correct order.

// Your Domain name with URL path or IP address with path
// Specify content-type header
http.addHeader("Content-Type", "application/x-www-form-urlencoded");
// Prepare your HTTP POST request data
String httpRequestData = "api_key=" + apiKeyValue + "&sensor=" + sensorName + "&location=" + sensorLocation + "&value1=" + String(bme.readTemperature()) + "&value2=" + String(bme.readHumidity()) + "&value3=" + String(bme.readPressure()/100.0F) + "";
int httpResponseCode = http.POST(httpRequestData);

Then there is another php page which reads the values from the database and creates the graphs passing the data to the Highcharts library.

var chartH = new Highcharts.Chart({
  chart:{ renderTo:'chart-humidity' },
  title: { text: 'Humidity' },
  series: [{
    showInLegend: false,
    data: value2
  plotOptions: {
    line: { animation: false,
      dataLabels: { enabled: true }
  xAxis: {
    type: 'datetime',
    //dateTimeLabelFormats: { second: '%H:%M:%S' },
    categories: reading_time
  yAxis: {
    title: { text: 'Humidity (%)' }
  credits: { enabled: false }

For complete codes refer to the GitHub repository.

Dark Mode

tempcontrol (this link opens in a new window) by mastroalex (this link opens in a new window)

The purpose of this project is to create a station for monitoring the environmental conditions for home.

Tasmota and smart home monitoring

It may be usefull to integrate these sensors with actuators. For example, it may be useful to activate a fan when a certain temperature is exceeded or to turn on a light when the ambient lighting falls up to more sophisticated controllers such as thermostats, dimmers for lighting, ventilation for air quality, etc.

A simple way to integrate the ESP platform with Alexa and the remote control of the actuators is the firmware offered by Tasmota. It is an alternative open source firmware that allows you to control different outputs on the ESP while also setting smart outputs, conditions and timers.

Just install the Tasmotizer software and load the correct firmware.

Software Tasmotizer
Webserver Tasmota. Input and output configuration.

Then you can connect to the ip address of the device and configure the desired outputs.

The system can be integrated with Alexa and accessible from a web server.

Real application – Prototype no. 2 – Device with Tasmota connected to 3 relays for 220V control and device with DHT11 for temperature and humidity detection.

Future developments

It is clear the possibility of optimizing everything by transferring it to a PCB circuit, eliminating all that is useless and using only the devices necessary for operation. This certainly implies an increase in production costs but would allow for a considerable reduction in size. It is clear that a large-scale production must be evaluated first and certainly not for the test phase.


24-hour reading of temperature and humidity from a room in July:

The graph contains a spline on the points obtained from a sampling every 5 minutes.

Reading in a week in July:


  • Termo Clima Service , for having supplied part of the material and equipment for the realization of the prototypes
  • Leto Informatics , for providing the hosting server and part of the configuration
  • Alina Elena Mihai, for graphics


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