SensorDataFirebase is a group of libraries that were created to help to send data from sensors to the Firebase RealTimeDatabase using some Arduino and one NodeMCU or Raspberry PI. The data sent to the Firebase is formated to help users to plot graph using the data.

Because the Raspberry and the NodeMCU work with 3.3V, sometimes can be difficult to use analog sensors (Raspberry problem) or sensors that send data with 5V (Raspberry and NodeMCU problem). The use of communication with some 5V Arduino solves this problem (the library do not work yet using only the Raspberry or NodeMCU).

The libraries allow the user to add as much sensor as (s)he wants. All the data colected about these sensors will be sent to the Firebase. Be warned: because sometimes it is slow to read data from the firebase using NodeMCU and Raspberry, the use of a lot of sensors can result in bugs.

First, is necessary to have created the "Real TimeDatabase" in your Firebase project. The data is stored only in this type of database. In the database is created two folders: "Sensors" and "Time". In the first folder is created a subfolder for each sensor. In the second folder is stored data about the current time ("CurrentTime") and current date ("CurrentDate").

The data from sensors are organized in 5 ways in each subfolder: Today, Yesterday, Week, Month, and Year.

In this folder is stored all the data collected today by that sensor. The data in this the folder "Today" is stored every 30 minutes. For each cycle a new variable will be created on the folder "Today" to store the average of all readings performed by that sensor (only data sent to the Arduino libray).

Every 00h00 all data stored in Today is copied to the subfolder "Yesterday". (The data in "Today" is deleted after copied)

Every 00h00 a variable is created in the subfolder "Week". This variable stores the mean of all data in "Today". The variable name can be:
"1" to Monday | "2" to Tuesday | "3" to Wednesday | "4" to Thursday | "5" to Friday | "6" to Saturday | "7" to Sunday

Every 00h00 a variable is created in the subfolder "Month". This variable stores the mean of all data in "Today". The variable name is the number of the day.

Every Monday 00h01 a variable is created in the subfolder "Year". This variable stores the mean of all data in "Week". The folder "Week" is deleted after this.

These libraries can work in two ways: the first one consists of using some Arduino and one NodeMCU; the second one consists of using some Arduino and one Raspberry.
In both systems the Arduino is connected to sensors and send the data to the other device. When the other device receive the bytes, it add the data to the Firebase Database and organize all the data.

To the library works the Arduino must be connected to some module that returns the time (I am using the DS1307 I2C RTC Module).
This information about the time is used to send all data in the right time to the other device. Information about the time is sent every minute and data about the sensors are sent every 30 minutes.

The communication between the Arduino and the NodeMCU is made through Serial. This communication occurs using 9600 or baudrate and Serial1 in both by default. (these values can be changed in the .cpp file).
The Node TX can be connected directily on the Arduino RX, but the voltage from the Arduino TX to the Node RX must be reduced. I am using one 1k resistor and one 2k2 resistor to lower the signal.

Do not forget to use some clock device.

The communication between the Arduino and the Raspberry is made through Serial too. This communication occurs by default using 9600 of baudrate, Serial1 for the Arduino and ttyAMA0 for the Raspberry. These values can be changed in the .cpp file for the Arduino and in the SensorFirebasePi.py for the Raspberry.

The connections between the Arduino and the Raspberry is very similar to the connection between the Arduino and the NodeMCU. The voltage divider (two resistors) is still required.

Copy the SensorDataFirebase-Arduino folder to your Documents/Arduino/Library folder.
After creating the object from the class SensorDataFirebaseArduino there are 3 main commands.
addSensor(String name) - This command is used to each sensors, the exactly same name must be used on the other commands.

updateValue(String name, float value) - This command is used to update each sensor data. A maximum of 30 numbers can be sent for the library on a period of 30 minutes.

run(int hour, int minute, int second, int day, int month, int year) - This command should be runned each minute. Data about the time will be sent to the other device each time and sensors data will be sent every 30 minutes.

/*Arduino CODE*/
#include "SensorDataFirebase-Arduino.h"
#include "Clock.h" // Use some library for your RTC clock device

SensorDataFirebaseArduino sensorData;

void setup() {
  sensorData.begin();
  sensorData.addSensor("temperature");//(String name, int codeCommunication)
}

int lastMinute;

void loop() {
    int hour,minute,second;

   rtclock.updateTime();
   minute = rtclock.getMinute();
   
  if (minute != lastMinute) {
    lastminute      = minute;
    int sensorValue = analogRead(A0);
    
    sensorData.updateValue("temperatura", sensorValue);//add new data to the temperature sensor
    
    sensorData.run( rtclock.getHour(), minute, rtclock.getSecond(), rtclock.getDayOfWeek(),
                    rtclock.getDay(), rtclock.getMonth(), rtclock.getYear());
  }
  delay(5);
}

To change the Serial port that will communicate with the other device go to SensorDataFirebase-Arduino.cpp and change the lines 11 and 12.

#define SerialToSend Serial1
#define isSerial0    false

Copy the SensorDataFirebase-NodeMCU folder to your Documents/Arduino/Library folder. After creating the object from the class SensorDataFirebaseNodeMCU there are 2 main commands.
addSensor(String name, String address) - This command is used to each sensors. The sequence you add the sensors must be the same on both files. Set the address as the address file in your Firebase where you want the data about this sensor to be stored.

run() - This command can be runned as much as you can. Every time this runs the data on the Serial port is checked and sent to the Firebase RealTimeDatabase.

To change the Serial port that will communicate with the other device go to SensorDataFirebase-NodeMCU.cpp and change the lines 14 and 15.

#define SerialToSend Serial1
#define isSerial0    false

You must change the lines 18-21 to connect the NodeMCU to your wifi and set your Firebase project.

#define FIREBASE_HOST "firebase link"
#define FIREBASE_AUTH "authCode"
#define WIFI_SSID "Name"
#define WIFI_PASSWORD "WifiPassword"

Also, you should to open your Firebase database to allow the NodeMCU to write and read data. Go to your Firebase project on the Firebase website and access your RealtimeDatabase. Go to the "rules" window and change read and write to true. Will look like this:

{
  /* Visit https://firebase.google.com/docs/database/security to learn more about security rules. */
  "rules": {
    ".read": true,
    ".write": true
  }
}

Nice, now you should be able to use the library properly. The example code is:

/*NodeMCU CODE*/
#include "SensorDataFirebase-NodeMCU.h"

SensorDataFirebaseNodeMCU sensorData;

void setup() {
  sensorData.begin();
  sensorData.addSensor("temperatura","Sensors/Temperature/");
}

void loop() {
  sensorData.run();
  delay(5);
}

Paste the folder SensorDataFirebase-Raspberry in your raspberry directory and create a python file inside this folder to code using this library (you can also access this library from another location). Follow the example.py to make your only code. The functions available for use on the Raspberry Library are:
addSensor(name, address) - This command is used to each sensors. The sequence you add the sensors must be the same on both files. Set the address as the address file in your Firebase where you want the data about this sensor to be stored.

run() - This command can be runned as much as you can. Every time this runs the data on the Serial port is checked and sent to the Firebase RealTimeDatabase.

sensorInfo(name) - This command is used to check the information about some sensor already added. this information is printed on the terminal.

/*Raspberry CODE*/
from firebase import firebase
from Libraries.SensorFirebasePi import SensorFirebasePi
import time

sensorData = SensorFirebasePi('https:/your-link.firebaseio.com/')

sensorData.addSensor('temperature','Sensors/Temperature/')
sensorData.addSensor('humidity','Sensors/Humidity/')
sensorData.sensorInfo('temperature')//It is not necessary
sensorData.sensorInfo('humidity')//It is not necessary

while True:
	sensorData.run()
	time.sleep(1)

This library was made to show everything it is doing to the user. Everytime the library read and send bytes it will be shown on the Monitor or Terminal. In addition, every time the library makes any changes to the firebase database, those changes will be displayed (read, write, remove).

There are two types of data to send. Data about sensors and data about the time.

When sending data about a sensor, this is shown:
Sending(sensor name) - bytes: b1 b2 b3 b4 - value: float value
Sending(temperature) - bytes: 16 17 227 65 - value: 28.383331

When sending data about time, this is shown:
Sending(time) - data: HH:MM:SS (DoW:Day of week) DD/MM/YYYY
Sending(time) - data: 22:1:0 (DoW:5) 15/3/2019

There are two types of data to be received. Data about sensors and data about the time.

When receiving data about a sensor, this is shown:
Receiving(sensor name) - bytes: b1 b2 b3 b4 - value: float value
Receiving(temperature) - bytes: 16 17 227 65 - value: 28.383331

When receiving data about time, this is shown:
Receiving(time) - data: HH:MM:SS (DoW:Day of week) DD/MM/YYYY
Receiving(time) - data: 22:1:0 (DoW:5) 15/3/2019

The library also print when some sensor data is being updated.
Updating(sensor name): float value
Updating(temperature): 28.383331

When adding or changing some value on Firebase, this is shown:
SET firebase: address = value
SET firebase: Time/CurrentTime = 22:04:00
SET firebase: Sensors/Temperature/Today/00h00 = 28.383331

When reading some value on Firebase, this is shown:
GET firebase: address: value
GET firebase: Sensors/Temperature/Today/00h00: 28.383331

When deleting some value on Firebase, this is shown:
DELETE firebase: address
DELETE firebase: Sensors/Temperature/Yesterday/

The library indicates the actual cycle (period of 30 minutes).
#--------------- CYCLE 21h30 ---------------#
Also, it indicates the start and end of some change. For example, if the library is changing information about the sensor temperature, it prints that this is ocurring.
#----- Sensor temperature -----#
#TODAY#
(The changes that are being made appear here)
#END#

Any doubt, error, or sugestion, please let me know.