Monitor room temperature, (ESP8266, BMP180, Blynk app).

You might probably have seen weather applications. You can get the temperature , humidity, air pressure and so on. However those readings are just an average value of big area. So, installing this system can help you monitor your room temperature and air pressure at anytime through the blynk app. You can monitor your data from your phone c:

This project can be applied into automatic AC controller. AC does have a temperature sensor in their unit but temperature in the room can`t be in uniformity. Their sensors are usually installed up high. That is why another temperature sensor from different place can compensate the error. Working like a second opinion. Making it more efficient in cooling and heating by AC.

And through the changing of the air pressure, we can anticipate the atmospheric condition. Pretty much ending up with self satisfaction.

Required components

1. ESP8266

2. BMP180

*Blynk app and Arduino IDE software is required.

What is ESP8266?

ESP8266 is a low-cost WiFi microchip produced by Espressif Systems in Shanghai, China. And it has a C＋＋ based firmware which make it possible to program like any other Arduino device.

About BMP180

It is a sensor that you can detect air pressure and temperature. It is designed to be connected via I2C bus.

Connectivity

BMP180 <–> ESP8266

VIN <——> 3.3V
GND <——> GND
SCL <——> D1
SDA <——-> D2

What is Blynk?

Blynk is a Platform with iOS and Android apps to control Arduino, Raspberry Pi and the likes over the Internet.

It`s a digital dashboard where you can build a graphic interface for your project by simply dragging and dropping widgets.

To set up Blynk app, go to

https://blynk.io/getting-started

Coding

okay, once you checked your connection, now you can do the programming. Connect your ESP8266 through USB and open Arduino IDE. You have to download library of BMP180.

Select the port and see if the code runs without error.

Download and include library,

ESP8266WiFi.h
BlynkSimpleEsp8266.h
Adafruit_BMP085.h

#define BLYNK_PRINT Serial    // Comment this out to disable prints and save space
#include <ESP8266WiFi.h>
#include <BlynkSimpleEsp8266.h>


#include <Wire.h>
#include <Adafruit_BMP085.h>



// You should get Auth Token in the Blynk App.
// Go to the Project Settings (nut icon).
char auth[] = "Your Auto token of blynk";  // Put your Auth Token here. 

BlynkTimer timer;

#define I2C_SCL 5     // Barometric Pressure Sensor (BMP085)
#define I2C_SDA 4
Adafruit_BMP085 bmp;

float dst,bt,bp,ba;
char dstmp[20],btmp[20],bprs[20],balt[20];
bool bmp085_present=true;

void setup()
{
  Serial.begin(9600); // See the connection status in Serial Monitor
   Blynk.begin(auth, "putSSIDhere", "putpasswordhere"); //insert here your SSID and password

 Wire.begin(I2C_SDA, I2C_SCL);
  delay(10);
if (!bmp.begin()) {
  Serial.println("Could not find a valid BMP085 sensor, check wiring!");
  while (1) {}
  }


 
  // Setup a function to be called every second
  timer.setInterval(10000L, sendUptime);
}

void sendUptime()
{
  // You can send any value at any time.
  // Please don't send more that 10 values per second.
   //Read the Temp and Humidity from DHT
   
  float bp =  bmp.readPressure();
  Blynk.virtualWrite(10, bp); // virtual pin

  float ba =  bmp.readAltitude();
  Blynk.virtualWrite(11, ba); // virtual pin

  float bt =  bmp.readTemperature();
  Blynk.virtualWrite(12, bt); // virtual pin

    float dst =  bmp.readSealevelPressure();
  Blynk.virtualWrite(13, dst); // virtual pin
  
}

void loop()
{

 Serial.print("Temperature = ");
    Serial.print(bmp.readTemperature());
    Serial.println(" *C");
    
    Serial.print("Pressure = ");
    Serial.print(bmp.readPressure());
    Serial.println(" Pa");
    
    // Calculate altitude assuming 'standard' barometric
    // pressure of 1013.25 millibar = 101325 Pascal
    Serial.print("Altitude = ");
    Serial.print(bmp.readAltitude());
    Serial.println(" meters");

    Serial.print("Pressure at sealevel (calculated) = ");
    Serial.print(bmp.readSealevelPressure());
    Serial.println(" Pa");


    Serial.println();
    delay(500);

  
  Blynk.run();
  timer.run();
}

Update

Blynk organization has done their update. And their service and functions are limited now. In this article, you can see that I displayed the air pressure and temperature data in the same graph. However, it seems like you can`t display two different data at the same time anymore in the free version unfortunately. (Update on 2024 Sep. 19th)