Sensor Box DIY (temp/humi/co2)

Here is a very nice little project to realize: A Sensor Box.

This small box, allows to control the temperature, humidity, as well as the level of CO2 in the air. In addition, all data is visible from a website hosted by ESP32 locally.

Here are the components you will need to realize this project! All links of components used are below

ESP32
SCD40/41
Battery
Female DC Connector
Switch 3 pins

Step 1 : Place the battery with a little hot glue in a corner

Step 2 : Place the DC Connector with some hot glue on the side to keep it in the intended location

Step 3 : Put the Switch 3 pin in the hole provided for this purpose

Step 4 : Solder the 3 pin Switch wires to the ESP32 power pins

Step 5 : With hot glue, glue the ESP32 against the bottom

Step 6 : Place the SCD40/41 sensor against the wall where the small ventilation holes are located

Step 7 : Connect the battery to the Switch 3 pins

Step 8 : Enjoy !!!

// The code for the ESP32, Sensor Box by Nitros : [https://makerworld.com/en/@Nitros](https://makerworld.com/en/@Nitros)

#include <Wire.h>
#include <WiFi.h>
#include <ESPmDNS.h>
#include <ESPAsyncWebServer.h>
#include <SparkFun_SCD4x_Arduino_Library.h>

const char* LOCALHOSTNAME = "esp32"; // You can change the name as you want
const char* SSID = "Your_SSID";
const char* PASSWORD = "Your_PASSWORD";

SCD4x scd4x;
AsyncWebServer server(80);

void setup() {
Serial.begin(115200);
Wire.begin();

WiFi.begin(SSID, PASSWORD);
while (WiFi.status() != WL_CONNECTED) {
  delay(1000);
  Serial.println("Connecting...");
}
Serial.print("Connected to WiFi : ");
Serial.println(WiFi.localIP());

MDNS.begin(LOCALHOSTNAME);

Serial.print("Local URL: [http://"](http://"));
Serial.print(LOCALHOSTNAME);
Serial.println(".local");

scd4x.begin();
scd4x.startPeriodicMeasurement();

server.on("/", HTTP_GET, [](AsyncWebServerRequest* request) {
  float CO2, TEMP, HUMI;
  if (scd4x.readMeasurement() == true) {
CO2 = scd4x.getCO2();
TEMP = scd4x.getTemperature();
HUMI = scd4x.getHumidity();
String htmlPage = "<!DOCTYPE html><html><head><meta charset='UTF-8'><meta http-equiv='refresh' content='10'><title>ESP32 SCD40 Data</title><style>";
htmlPage += "body {font-family: Arial, sans-serif; display: flex; flex-direction: column; align-items: center; justify-content: center; height: 100vh; background-color: #f4f4f9; margin: 0;}";
htmlPage += "h1 {color: #333;}";
htmlPage += ".card {background-color: white; box-shadow: 0 4px 8px rgba(0,0,0,0.1); border-radius: 10px; padding: 20px; margin: 10px; text-align: center; width: 300px;}";
htmlPage += ".value {font-size: 2em; margin: 10px 0;}";
htmlPage += ".label {font-size: 1em; color: #555;}";
htmlPage += "</style></head><body><h1>ESP32 SCD40 Data</h1>";
htmlPage += "<div class='card'><div class='label'>CO2 (ppm)</div><div class='value'>" + String(CO2, 2) + "</div></div>";
htmlPage += "<div class='card'><div class='label'>Temperature (°C)</div><div class='value'>" + String(TEMP, 2) + "</div></div>";
htmlPage += "<div class='card'><div class='label'>Humidity (%)</div><div class='value'>" + String(HUMI, 2) + "</div></div>";
htmlPage += "</body></html>";
  request->send(200, "text/html", htmlPage);
}
});
server.begin();
}

void loop() {
}

To view data from the web server hosted by the esp32. You must connect to the same network as the esp32. Then, you enter the IP address of the esp32 or with [http://esp32.local](http://esp32.local) (LOCALHOSTNAME) (knowing that when I use the url, it only works on computer and not on phone).

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