RAK1921_OLED_SSD1306.ino

/**
   @file RAK1921_OLED_SSD1306.ino
   @author rakwireless.com
   @brief a environment show about the oled.
   @version 0.1
   @date 2020-12-28
   @copyright Copyright (c) 2020
**/

#include <Wire.h>
#include <Adafruit_Sensor.h>
#include <Adafruit_BME680.h> // Click to install library: http://librarymanager/All#Adafruit_BME680
#include <U8g2lib.h>		   // Click to install library: http://librarymanager/All#u8g2

U8G2_SSD1306_128X64_NONAME_F_HW_I2C u8g2(U8G2_R0);
Adafruit_BME680 bme;

void bme680_init()
{
  Wire.begin();

  if (!bme.begin(0x76)) {
    Serial.println("Could not find a valid BME680 sensor, check wiring!");
    return;
  }

  // Set up oversampling and filter initialization
  bme.setTemperatureOversampling(BME680_OS_8X);
  bme.setHumidityOversampling(BME680_OS_2X);
  bme.setPressureOversampling(BME680_OS_4X);
  bme.setIIRFilterSize(BME680_FILTER_SIZE_3);
  bme.setGasHeater(320, 150); // 320*C for 150 ms
}

void bme680_get()
{
	char data[32] = {0};
	double temp = bme.temperature;
	double pres = bme.pressure / 100.0;
	double hum = bme.humidity;

	Serial.print("T=");
	Serial.print(temp);
	Serial.print("C, RH=");
	Serial.print(hum);
	Serial.print("%, P=");
	Serial.print(pres);
	Serial.print("hPa");

	float gas = bme.gas_resistance / 1000.0;

	Serial.printf(", G= %.3f kOhms\n",gas);

	// display bme680 sensor data on OLED
	u8g2.clearBuffer();					// clear the internal memory
	u8g2.setFont(u8g2_font_ncenB10_tr); // choose a suitable font

	memset(data, 0, sizeof(data));
	sprintf(data, "T=%.2fC", temp);
	u8g2.drawStr(3, 15, data);

	memset(data, 0, sizeof(data));
	snprintf(data, 64, "RH=%.2f%%", hum);
	u8g2.drawStr(3, 30, data);

	memset(data, 0, sizeof(data));
	sprintf(data, "P=%.2fhPa", pres);
	u8g2.drawStr(3, 45, data);

	memset(data, 0, sizeof(data));
	sprintf(data, "G=%.3f kOhms", gas);
	u8g2.drawStr(3, 60, data);

	u8g2.sendBuffer(); // transfer internal memory to the display
}

void setup()
{
  // Initialize the built in LED
  pinMode(LED_BUILTIN, OUTPUT);
  digitalWrite(LED_BUILTIN, LOW);

  // Initialize Serial for debug output
  Serial.begin(115200);

  time_t serial_timeout = millis();
  // On nRF52840 the USB serial is not available immediately
  while (!Serial)
  {
    if ((millis() - serial_timeout) < 5000)
    {
      delay(100);
      digitalWrite(LED_BUILTIN, !digitalRead(LED_BUILTIN));
    }
    else
    {
      break;
    }
  }

  bme680_init();
	u8g2.begin();
}

void loop()
{
  if (! bme.performReading()) 
  {
    Serial.println("Failed to perform reading :(");
  }
  bme680_get();
  delay(5000);
}