• Author: Chirilă Alexandru

This project is meant to monitor the temperature for a certain room: the room where the sensor will be placed. It only prints data when the temperature changes by at least 0.5 °C since the last printed temperature value. It also plays a notification sound when this change of temperature occurs. It is a simplist project consisting of two parts:

1. An arduino program which monitors the temperature and sends it to a Firebase database
2. A Python script which can be run on any computer or even an Android phone or an iPhone (Python interpreter installation required)

Following hardware components were used in order to achieve the desired result:

• ESP32 Sparrow
• BME680 Sensor

The following libraries were necessary:

#include "Zanshin_BME680.h"
#include <Arduino.h>
#include <WiFi.h>
#include <Firebase_ESP_Client.h>

The Wi-Fi setup and connection:

WiFi.begin (WIFI_SSID, WIFI_PASSWORD);
Serial.print("Connecting to Wi-Fi...");
while (WiFi.status() != WL_CONNECTED) {
  Serial.print(".");
  delay(300);
}

The BME680 setup:

// Code taken from the "I2CDemo" example.
BME680_Class BME680;
float altitude(const int32_t press, const float seaLevel = 1013.25);
float altitude(const int32_t press, const float seaLevel) {
 static float Altitude;
 Altitude = 44330.0 * (1.0 - pow(((float)press / 100.0) / seaLevel, 0.1903));
 return (Altitude);
}

Firebase setup:

config.api_key = API_KEY;
config.database_url = DATABASE_URL;
/* Sign up */
if (Firebase.signUp(&config, &auth, "", "")) {
  Serial.println("ok");
  signupOK = true;
}
else {
  Serial.printf("%s\n", config.signer.signupError.message.c_str());
}
/* Assign the callback function for the long running token generation task */
config.token_status_callback = tokenStatusCallback; //see addons/TokenHelper.h
Firebase.begin(&config, &auth);
Firebase.reconnectWiFi(true);

The loop() function:

void loop() {
  if (Firebase.ready() && signupOK && (millis() - sendDataPrevMillis > 1000 || sendDataPrevMillis == 0)) {
    sendDataPrevMillis = millis();    
    static int32_t  temp, humidity, pressure, gas;  // BME readings
    BME680.getSensorData(temp, humidity, pressure, gas);
 
    if (Firebase.RTDB.setFloat(&fbdo, "test/float", (float)(temp / 100.0f))) {
      Serial.println("PASSED");
      Serial.println("PATH: " + fbdo.dataPath());
      Serial.println("TYPE: " + fbdo.dataType());
    }
    else {
      Serial.println("FAILED");
      Serial.println("REASON: " + fbdo.errorReason());
    }
  }
}

As said before, the data read from sensor is saved in Firebase and is updated in real time in the output of the python script.

Running the python script is as follows:

https://randomnerdtutorials.com/esp32-firebase-realtime-database/