Hello readers, I hope you all are doing great. In this tutorial, we will learn how to interface the BMP280 sensor with the ES32 module to get temperature, pressure and altitude readings. Later, in this tutorial, we will also discuss how to upload these sensor readings to a web server.
| Where To Buy? | ||||
|---|---|---|---|---|
| No. | Components | Distributor | Link To Buy | |
| 1 | ESP32 | Amazon | Buy Now | |
BMP280 or Barometric pressure sensor is a module used to measure temperature pressure and altitude. The small size and low power consumption feature of this sensor makes it feasible for battery-powered devices, GPS modules and mobile applications etc.
Fig. 1 BMP280 Sensor
The BMP280 is the product of BOSCH which is based on Bosch’s proven Piezo-resistive pressure sensor technology featured with high accuracy, long term stability, linearity and high EMC robustness.
BMP280 is the successor of the BMP180 sensor and offers high performance in all the areas that require precise temperature and pressure measurements.
Emerging applications like fitness, indoor navigation, GPS refinement requires relative accuracy and BMP280 is perfect for such applications. Very low TCO (Temperature coefficient of Offset ) makes this module preferable over other available modules for temperature measurements.
We can also use a DHT11/DHT22 sensor for temperature and humidity measurements but the BMP280 sensor provides better accuracy (i.e., 0.01°C) than DHT sensors.
There are two methods of interfacing BMP280 sensor with ESP32 module:
In the bMP280 Sensor module, there are six interfacing pins including VCC and GND.
Fig. Interfacing BMP280 and ESP32
We are using the I2C protocol for interfacing the two (ESP and BMP280) so only SCL and SDA pins will be used with power pins for interfacing. The SDO and CSB pins will be used only if you are using the SPI protocol for interfacing.
Table 1
We are using Arduino IDE to compile and upload code into the ESP32 module. You must have ESP32 board manager installed on your Arduino IDE to program the ESP32 module. To know more about Arduino IDE and how to use it, follow our previous tutorial i.e., on ESP32 programming series. The link is given below:
https://www.theengineeringprojects.com/2021/11/introduction-to-esp32-programming-series.html
Steps to add the necessary libraries in Arduino IDE:
Fig. 2 manage libraries
Fig. 3 Install library
#include <Wire.h>
void setup()
{
Wire.begin();
Serial.begin(115200);
Serial.println("\nI2C Scanner");
}
void loop()
{
byte error, address;
int nDevices;
Serial.println("Scanning...");
nDevices = 0;
for(address = 1; address < 127; address++ )
{
Wire.beginTransmission(address);
error = Wire.endTransmission();
if (error == 0)
{
Serial.print("I2C device found at address 0x");
if (address<16)
{
Serial.print("0");
}
Serial.println(address,HEX);
nDevices++;
}
else if (error==4)
{
Serial.print("Unknow error at address 0x");
if (address<16) {
Serial.print("0");
}
Serial.println(address,HEX);
}
}
if (nDevices == 0) {
Serial.println("No I2C devices found\n");
}
else {
Serial.println("done\n");
}
delay(5000);
}
#include <Wire.h>
#include <Adafruit_BMP280.h>
#define BMP_SDA 21
#define BMP_SCL 22
Adafruit_BMP280 bmp280;
void setup()
{
Serial.begin(115200);
Serial.println("Initializing BMP280");
boolean status = bmp280.begin(0x76);
if (!status)
{
Serial.println("Not connected");
}
}
void loop()
{
float temp = bmp280.readTemperature();
Serial.print("temperature: ");
Serial.print(temp);
Serial.println("*C");
float altitude = bmp280.readAltitude(1011.18);
Serial.print("Altitude: ");
Serial.print(altitude);
Serial.println("m");
float pressure = (bmp280.readPressure()/100);
Serial.print("Pressure: ");
Serial.print(pressure);
Serial.println("hPa");
Serial.println(" ");
delay(1000);
}
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10 Select development board and COM port
Fig. 11 Serial monitor output
Most of the industries and organizations these days are shifting to the efficient ways of operating things and the IoT internet of things is one of them.
Internet of Things is a system of multiple inter-related computing devices. The factor ‘thing’ in IoT is designated to an entity capable of communicating data over a network (IOT), which can be a digital machine, sensor, human being, animals etc.
Each component that is included in IoT network is assigned with an unique identity called UID and the ability to communicate data over IoT network without any external human or computer intervention.
Fig. 12 IoT
ThingSpeak is an open data platform for the Internet of Things applications. It is a MathWorks web service that allows users to send sensor readings and data to the cloud. We can also visualize and act on the data (calculate the data) that is sent to ThingSpeak by the devices. The information can be saved in both private and public channels.
ThingSpeak is frequently used for IoT prototyping and proof-of-concept devices that require data analysis.
Downloading and installing the required Library file:
https://github.com/mathworks/thingspeak-arduino
Fig. 13 Adding ThingSpeak library
To check whether the library is successfully added or not:
Fig. 14
Fig, 15 Arduino IDE Library manager
Fig. 16 Getting started for free
Fig. 17 Create new account
Fig. 18 MathWorks Sign in
Fig. 19 New Channel
Fig. 20 Creating channel and respective fields
Fig. 21 save the channel
Fig. 22 Field Chart Edit
// ------style guard ----
#ifdef __cplusplus
extern "C"
{
#endif
uint8_t temprature_sens_read();
#ifdef __cplusplus
}
#endif
uint8_t temprature_sens_read();
// ------header files----
#include <WiFi.h>
#include "ThingSpeak.h"
#include <Wire.h>
#include <Adafruit_BMP280.h>
#define BMP_SDA 21
#define BMP_SCL 22
Adafruit_BMP280 bmp280;
// -----netwrok credentials
const char* ssid = "public"; // your network SSID (name)
const char* password = "ESP32@123"; // your network password
WiFiClient client;
// -----ThingSpeak channel details
unsigned long myChannelNumber = 4;
const char * myWriteAPIKey = "9R3JZEVBG73YE8BY";
// ----- Timer variables
unsigned long lastTime = 0;
unsigned long timerDelay = 1000;
void setup()
{
Serial.begin(115200); // Initialize serial
Serial.println("Initializing BMP280");
boolean status = bmp280.begin(0x76);
if (!status)
{
Serial.println("Not connected");
}
//Initialize Wi-Fi
WiFi.begin(ssid, password);
Serial.print("Connecting to Wi-Fi");
while (WiFi.status() != WL_CONNECTED)
{
Serial.print(".");
delay(100);
}
Serial.println();
Serial.print("Connected with IP: ");
Serial.println(WiFi.localIP());
Serial.println();
// Initialize ThingSpeak
ThingSpeak.begin(client);
}
void loop()
{
if ((millis() - lastTime) > timerDelay )
{
float temp = bmp280.readTemperature(); //temperature measurement
Serial.print("temperature: ");
Serial.print(temp);
Serial.println("*C");
float altitude = bmp280.readAltitude(1011.18); //altitude measurement
Serial.print("Altitude: ");
Serial.print(altitude);
Serial.println("m");
float pressure = (bmp280.readPressure()/100); //pressure measurement
Serial.print("Pressure: ");
Serial.print(pressure);
Serial.println("hPa");
Serial.println(" ");
ThingSpeak.setField(1, temp );
ThingSpeak.setField(2, altitude);
ThingSpeak.setField(3, pressure);
// Write to ThingSpeak. There are up to 8 fields in a channel, allowing you to store up to 8 different
// pieces of information in a channel. Here, we write to field 1.
int x = ThingSpeak.writeFields(myChannelNumber,
myWriteAPIKey );
if(x == 200)
{
Serial.println("Channel update successful." );
}
else
{
Serial.println("Problem updating channel. HTTP error code " + String(x) );
}
lastTime = millis();
}
}
We are describing only the ThingSpeak server part as the BMP280 and ESP32 interfacing part has already been discussed in the above code description.
Fig. 23 Style guard
Fig. 24 Libraries
Fig. 25
Fig. 26
Fig. 27
Fig. 28
Fig. 29
Fig. 30
Fig. 31
Fig. 32 Sensor readings
Fig. 33 setting respective Fields
Fig. 34
Fig. 35
Fig. 36 ThingSpeak server
Fig. 37 Sensor readings on the Serial monitor
This concludes the tutorial. I hope you found this of some help and also hope to see you soon with a new tutorial on ESP32.