ESP32 with BMP180 Barometric Sensor – Guide

This guide shows you how to use the BMP180 barometric sensor with the ESP32 to read pressure, temperature and estimate altitude. We’ll show you how to wire the sensor to the ESP32, install the needed library, and how to write the sketch in the Arduino IDE.

Introducing the BMP180 Barometric Sensor

The BMP180 is a digital pressure sensor and it measures the absolute pressure of the air around it.

It features a measuring range from 300 to 1100hPa with an accuracy down to 0.02 hPa.

Because temperature affects the pressure, the sensor comes with a temperature sensor to give temperature compensated pressure readings.

Additionally, because the pressure changes with altitude, you can also estimate the altitude based on the current pressure measurement.

Wiring BMP180 Sensor to the ESP32

The BMP180 barometric sensor uses I2C communication protocol. So, you need to use the SDA and SCL pins of the ESP32.

The following table shows how to wire the sensor.

Reading Temperature, Pressure, And Altitude

In this section we’ll show you how to read pressure and temperature from the BMP180 barometric sensor using the ESP32. We’ll also show you how to estimate altitude.

Parts required

For this example, you need the following parts:

• ESP32 Module (ESP32 DOIT DEVKIT V1 Board) – read ESP32 development boards comparison
• BMP180 barometric sensor
• Jumper wires

Schematic

Wire the BMP180 barometric sensor to the ESP32 as shown in the following schematic diagram.

Preparing the ESP32 board in Arduino IDE

In order to upload code to your ESP32 using Arduino IDE, you should install an add-on for the Arduino IDE that allows you to program the ESP32 using the Arduino IDE and its programming language. Follow one of the next tutorials to prepare your Arduino IDE:

• Windows instructions – Installing the ESP32 Board in Arduino IDE
• Mac and Linux instructions – Installing the ESP32 Board in Arduino IDE

Installing the BMP_085 Library

One of the easiest ways to read pressure, temperature and altitude with the BMP180 sensor is using the BMP_085 library by Adafruit. This library is compatible with the BMP085 and the BMP180 sensors. Follow the next steps to install the library in your Arduino IDE:

Open your Arduino IDE and go to Sketch > Include Library > Manage Libraries. The Library Manager should open.

Search for “BMP085” on the Search box and install the BMP085 library from Adafruit.

After installing, restart your Arduino IDE.

Code

The library provides an example showing how to get temperature, pressure, and altitude. Go to File > Examples > Adafruit BMP085 Library > BMP085test.

/*
 * Gnd_To_Vcc
 
*/

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

Adafruit_BMP085 bmp;
  
void setup() {
  Serial.begin(9600);
  if (!bmp.begin()) {
	Serial.println("Could not find a valid BMP085/BMP180 sensor, check wiring!");
	while (1) {}
  }
}
  
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");

  // you can get a more precise measurement of altitude
  // if you know the current sea level pressure which will
  // vary with weather and such. If it is 1015 millibars
  // that is equal to 101500 Pascals.
  Serial.print("Real altitude = ");
  Serial.print(bmp.readAltitude(102000));
  Serial.println(" meters");
    
  Serial.println();
  delay(500);
}

The code starts by importing the needed libraries:

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

You create an Adafruit_BMP085 object called bmp.

Adafruit_BMP085 bmp;

In the setup() the sensor is initialized:

void setup() {
  Serial.begin(9600);
  if (!bmp.begin()) {
	Serial.println("Could not find a valid BMP085/BMP180 sensor, check wiring!");
	while (1) {}
  }
}

Reading Temperature

To read the temperature you just need to use the readTemperature() method on the bmp object:

bmp.readTemperature()

Reading Pressure

Reading the pressure is also straighforward. You use the readPressure() method.

bmp.readPressure()

The pressure readings are given in Pascal units.

Reading Altitude

Because the pressure changes with altitude, you can estimate your current altitude by comparing it with the pressure at the sea level.

The example gives you two different ways to estimate altitude.

1. The first assumes a standard barometric pressure of 10132 Pascal at the sea level. You get the altitude as follows:

bmp.readAltitude()

2. The second method assumes the current pressure at the sea level. For example, if at the moment the pressure at the sea level is 101500 Pa, you just need to pass 101500 as an argument to the readAltitude() method as follows:

bmp.readAltitude(101500)

Demonstration

Upload the code to your ESP32. Make sure you have the right board and COM port selected.

Then, open the Serial Monitor at a baud rate of 9600. You should get the sensor readings, as shown in the following figure.

Wrapping Up

In this guide we’ve shown you how to use the BMP180 barometric sensor with the ESP32 to read pressure, temperature and estimate altitude.

Now, you can take this project further and display the latest sensor readings on a web server. We have several examples you can modify to display the readings:

• ESP32 Web Server with BME280 – Mini Weather Station
• ESP32 DHT11/DHT22 Web Server – Temperature and Humidity using Arduino IDE

We hope you’ve found this guide useful. If you like ESP32, make sure you take a look at the following resourceS:

• Getting Started with ESP32
• ESP32 Pinout Reference: Which GPIO pins should you use?
• ESP32 Web Server – Arduino IDE

Thanks for reading