Using BMP280 to make a weather station

The project is a weather station that displays the local atmospheric pressure, temperature humidity and UV index without any internet connection.

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For a long time I wanted to make a weather station without the use of the internet, to measure the weather data around you and view the data when needed. So, I set out to make a cool looking local weather station that can measure the air pressure, temperature, humidity around you and the UV index of the day (if you place it near a window). It also has a clock screen to show the time, date and day of the week.

In this article, I will show you how to make this cool weather station in just a few steps.

Step 1: Build the enclosure

I created the shell using Autodesk fusion 360 and printed it in green PLA. It needed supports and I printed it on my Ender 3 at 70mm/s with 20% infill.

Step 2: BMP280

BMP280 is an atmospheric pressure and temperature sensor, which uses I2C or SPI protocol to communicate with Arduino . Here I use SPI. To use SPI, connect -

CS to D10

SDA to D11

SDO to D12

SCK to D13

In the code section, to use this sensor, we need a library. First, I included the library in the code #include < Adafruit_BMP280.h>. You can find the jump below this article.

Then I define the SPI pins of the sensor. In the setup function I initialize the BMP sensor and in the loop function I read the pressure and temperature data using the bmp.readPressure() and bmp.readTemperature() commands. I divide the pressure value by 100 to measure the pressure in hPa. To measure the altitude I use the bmp.readAltitude(1005.47) command. In this step you have to change the value according to the average pressure in your area. (1005.47)

Step 3: DS3231 RTC

This weather station also has a time screen which can show the current time, date and day of the week. For this purpose, I have used a DS231 RTC module which uses the I2C protocol for communication. So to use this, connect -

SCL to A5

SDA to A4

First you must set the time and date on the RTC using the DS3231_set.ino program from the library examples.

In the main program, I include the library #include <DS3231.h> and read the time data according to the instructions in the library. Here I use the examples in the library as a reference for the code. I created a case for each day of the week to find the current date.

Step 4: DHT11

I use this sensor to measure humidity. For this, I connect its data to Arduino D2. In the program, I include the DHT library, #include <DHT.h> and then initialize the sensor in the setup. In the loop, I read the humidity value using the dht.readHumidity() command.

Step 5: GUVA-S12SD UV Sensor

GUVA-S12SD is a Schottky type photodiode based on Gallium Nitride . It has a typical UV detection wavelength of 240-370nm (covering UVB and most of the UVA spectrum). It outputs a calibrated analog voltage that varies with the intensity of UV light. Therefore, we can read the analog value through the Arduino ADC.

In the loop function I simulate reading the sensor value and calculating the UV index

float sens orValue = analogRead(A0);

float sensorVoltage = sensorValue / 1024 * 5.0;

int UV_index = sensorVoltage / 0.1;

Step 6: OLED Display

I am using 0.96" 128*64 OLED display in this project, it uses I2C protocol, so I connected it to Arduino as shown below -

SCK to A5

SDA to A4

In the program, I first covered the Adafruit_SSD1306 and Adafruit_GFX libraries

#include 《Adafruit_GFX.h》

#include "Adafruit_SSD1306.h"

Then I create the display variable and add some bitmaps to show some images. In the setup, I initialize the display. Then in the loop, I use the display.print() function to display each data. I display the data on four pages, time, pressure, temperature and humidity, and UV_index. There is a 5 second delay between each page.

Local weather station code:

#include

#include

Then I create the display variable and add some bitmaps to show some images. In the setup, I initialize the display. Then in the loop, I use the display.print() function to display each data. I display the data on four pages, time, pressure, temperature and humidity, and UV_index. There is a 5 second delay between each page.

Local weather station code:

#include

#include

#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
#define OLED_RESET 4
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

#define BMP_SCK (13)
#define BMP_MISO (12)
#define BMP_MOSI (11)
#define BMP_CS (10)

DS3231 clock;
bool century = false;
bool h12Flag;
bool pmFlag;

Adafruit_BMP280 bmp(BMP_CS, BMP_MOSI, BMP_MISO, BMP_SCK);

#define DHT PIN 2
#define DHTTYPE DHT11
DHT dht(DHTPIN, DHTTYPE);

const unsigned char PROGMEM frame0 [] = {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0xFF, 0x80, 0x00, 0x00, 0x0F, 0xFF, 0xF0, 0x00, 0x00, 0x3F, 0xFF, 0xFC, 0x00, 0x00, 0x7F, 0x81, 0xFE, 0x00, 0x00, 0xFC, 0x00, 0x3F, 0x00, 0x01, 0xF0, 0x00, 0x0F, 0x80, 0x03, 0xE0, 0x18, 0x07, 0xC0, 0x07, 0x86, 0x18, 0x61, 0xE0, 0x0F, 0x02, 0x00, 0x40, 0xF0, 0x0F, 0x02, 0x00, 0x40, 0xF0, 0x1E, 0x00, 0x00, 0x00, 0x78, 0x1C, 0x40, 0x00, 0x02, 0x38, 0x3C, 0x61, 0x00, 0x06, 0x3C, 0x3C, 0x01, 0x80, 0x00, 0x3C, 0x38, 0x00, 0x80, 0x00, 0x1C, 0x38, 0x00, 0xC0, 0x00, 0x1C, 0x78, 0x00, 0xE0, 0x00, 0x1E, 0x79, 0xC0, 0xF0, 0x03, 0x9E, 0x79, 0xC0, 0x7C, 0x03, 0x9E, 0x78, 0x00, 0x7E, 0x00, 0x1E, 0x38, 0x00, 0x7E, 0x00, 0x1C, 0x38, 0xFC, 0xFF, 0x3F, 0x1C, 0x3C, 0xFC, 0x7E, 0x3F, 0x3C, 0x3C, 0xFE, 0x7E, 0x7F, 0x3C, 0x1C, 0x7E, 0x18, 0x7E, 0x38, 0x1E, 0x3F, 0x00, 0xFC, 0x78, 0x0F, 0x3F, 0xC3, 0xFC, 0xF0, 0x0F, 0x0F, 0xFF, 0xF8, 0xF0, 0x07, 0x87, 0xFF, 0xE1, 0xE0, 0x03, 0xC1, 0xFF, 0x83, 0xC0, 0x03, 0xF0, 0x3C, 0x0F, 0xC0, 0x01, 0xFC, 0x00, 0x3F, 0x80, 0x00, 0x7F, 0x81, 0xFE, 0x00, 0x00, 0x3F, 0xFF, 0xFC, 0x00, 0x00, 0x0F, 0xFF, 0xF0, 0x00, 0x00, 0x01, 0xFF, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
const unsigned char PROGMEM frame1 [] = {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x18, 0x00, 0x00, 0x00, 0x00, 0x7E, 0x00, 0x00, 0x00, 0x00, 0xC3, 0x00, 0x00, 0x01, 0x00, 0x9D, 0x80, 0x00, 0x03, 0x80, 0xB4, 0xE0, 0x00, 0x06, 0x80, 0xA6, 0x80, 0x00, 0x04, 0xC0, 0xA6, 0xE0, 0x00, 0x0C, 0x40, 0xA6, 0xE0, 0x00, 0x08, 0x60, 0xA6, 0x80, 0x00, 0x08, 0x20, 0xA6, 0xE0, 0x00, 0x08, 0x60, 0xA6, 0x80, 0x00, 0x0E, 0xC0, 0xA6, 0xE0, 0x00, 0x03, 0x80, 0xA6, 0x80, 0x00, 0x00, 0x10, 0xA6, 0xC0, 0x00, 0x00, 0x38, 0xA6, 0xE0, 0x00, 0x00, 0x38, 0xA6, 0x80, 0x00, 0x00, 0x6C, 0xA6, 0xE0, 0x00, 0x00, 0x44, 0xA6, 0x80, 0x00, 0x00, 0x6C, 0xA6, 0xE0, 0x00, 0x00, 0x38, 0xA6, 0x80, 0x00, 0x00, 0x00, 0xA6, 0x80, 0x00, 0x00, 0x00, 0xA4, 0xE0, 0x00, 0x00, 0x00, 0xA6, 0x80, 0x00, 0x00, 0x40, 0xA6, 0xE0, 0x00, 0x00, 0xC0, 0xA6, 0x80, 0x00, 0x01, 0xA0, 0xA6, 0xE0, 0x00, 0x01, 0x30, 0xA6, 0xE0, 0x00, 0x03, 0x10, 0xA6, 0x80, 0x00, 0x02, 0x18, 0xA6, 0xE0, 0x00, 0x06, 0x08, 0xA6, 0x80, 0x00, 0x06, 0x08, 0xA6, 0x80, 0x00, 0x02, 0x19, 0xA6, 0xC0, 0x00, 0x03, 0xF3, 0x26, 0x60, 0x00, 0x00, 0xC6, 0x26, 0x30, 0x00, 0x00, 0x0C, 0xE3, 0x10, 0x00, 0x00, 0x09, 0x80, 0x98, 0x00, 0x00, 0x19, 0x00, 0xC8, 0x00, 0x00, 0x13, 0x00, 0x6C, 0x00, 0x00, 0x12, 0x00, 0x6C, 0x00, 0x00, 0x12, 0x00, 0x6C, 0x00, 0x00, 0x12, 0x00, 0x6C, 0x00, 0x00, 0x1B, 0x00, 0x4C, 0x00, 0x00, 0x09, 0x80, 0xC8, 0x00, 0x00, 0x0C, 0xC1, 0x98, 0x00, 0x00, 0x04, 0x7F, 0x30, 0x00, 0x00, 0x06, 0x1C, 0x60, 0x00, 0x00, 0x03, 0x81, 0xC0, 0x00, 0x00, 0x00, 0xFF, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
const unsigned char PROGMEM frame2 [] = {0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x80};

void setup() {
Serial.begin(57600);
if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
 Serial.println(F("SSD1306 fai led"));
}
Wire.begin();
dht.begin( );
if (!bmp.begin()) {
 Serial.println(F("Problem.bmp"));
 while (1) delay(10);
}
display.clearDisplay();
display.setTextColor(WHITE);
display.setTextSize(1);
display.setCu rsor(0 , 9);
display.se tFont(&FreeSans9pt7b);
display.println("**** LOCAL ****");
display.setCursor(0, 38);
display.setFont(&FreeMonoBo ldOblique12pt7b);
display.println("wather");
display.setCursor(27, 58);
display.println("Station");
display.display();
delay(2000);

bmp.setSampling(Adafruit_BMP280::MODE_NORMAL, /* Operating Mode. */
Adafruit_BMP280::SAMPLING_X2, /* Temp. oversampling */
Adafruit_BMP280::SAMPLING_X16, /* Pressure oversampling */
Adafruit_BMP280::FILTER_X16, /* Filtering. */
Adafruit_BMP280::STANDBY_MS_500); /* Standby time. */

}

void loop() {

//Time
display.clearDisplay();
display.setTextColor(WHITE);
display.setTextSize(1);
display.setCursor(13, 15);
display.setFont(&FreeMonoBoldOblique12pt7b);
display.print(clock.getHour(h12Flag, pmFlag) ));
display.setCursor(38, 15);
display.println(":");
display.setCursor(50, 15);
display.println(clock.getMinute());
display.setCursor(70, 15);
if (pmFlag) {
 display.println(" PM" );
} else {
 display.println(" AM ");
}
display.setFont(&FreeSans9pt7b);

display.setCursor(20, 60);
display.println(clock.getDate());
display.setCursor(40, 60);
display.println("/");
display.setCursor(46, 60);
display.println (clock.getMonth(century));
display.setCursor(65, 60);
display.println("/");
display.setCursor(70, 60);
display.println("20");
display.setCursor(90, 60);
display.println(clock.getYear());
display.setCursor(30, 30);
display.setFont (&FreeSans9pt7b);
switch (clock.getDoW()) {
 case 1:
  display.println("Saturday");
  break;
 case 2:
  display.println("Sunday");
  break;
 case 3:
  display.println("Monday");
  break;
 case 4:
  display.println("Tu esday");
  break;
 case 5:
  display.println("Wednesday");
  break;
 case 6:
  display.println("Thursday" );
  break;
 case 7:
  display.println("Friday");
  break;
}

display.display();
delay(5000);
//P
display.clearDisplay();
display.drawBitmap(0, 0, frame0, 40, 40, 1);
display.setFont(&FreeSans9pt7b);
display.setCursor(41, 28);
display.println(bmp.readPressure() / 100);
display.setCursor(110, 28);
display.setFont();
display.println("hPa");
display.setCursor(0, 55);
display.setFont(&FreeSans9pt7b);
display.println("Altitude:");
display.setCursor(65, 62);
display.println(bmp.readAltitude(1005.47));
display.setCursor(113, 62);
display.println("m");
display.display();
delay(5000);
//T&RH
display.clearDisplay();
display.setFont(&FreeMonoBoldOblique12pt7b);
display.drawBitmap(0, 5, frame1, 40, 51, 1);
display.setCursor(35, 30);
display.print(bmp.readTemperature( ));
display.setFont(&FreeSans9pt7b);
display.setCursor(102, 28);
display.println(" *");
display.setCursor(110, 31);
display.println(" C");
display.setFont();
display.setCursor(66, 45) ;
display.println("RH :");
byte RH = dht.readHumidity();
display.setCursor(95, 45);
display.println(RH);
display.setCursor(110, 45);
display.println("%");
display.drawBitmap(0, 56, frame2, 135, 15, 1);
display.display();
delay(5000);
//UV
display.clearDisplay();
float sensorValue = analogRead (A0);
float sensorVoltage = sensorValue / 1024 * 5.0;
int UV_index = sensorVoltage / 0.1;
display.setFont(&FreeSans9pt7b);
display.setCursor(0, 15);
display.print(" UV INDEX ");
display.setCursor(58, 45);
display.println(UV_index);
display.display();
delay( 5000);
}