Arduino Wiring & Test

You can easily wire this breakout to any microcontroller, we'll be using an Arduino compatible. For another kind of microcontroller, as long as you have 4 available pins it is possible to 'bit-bang SPI' or you can use two I2C pins, but usually those pins are fixed in hardware. Just check out the library, then port the code.

I2C Wiring

Use this wiring if you want to connect via I2C interface

By default, the i2c address is 0x77.  If you add a jumper from SDO to GND, the address will change to 0x76.

 

  • Connect Vin to the power supply, 3-5V is fine. Use the same voltage that the microcontroller logic is based off of. For most Arduinos, that is 5V. For 3.3V logic devices, use 3.3V
  • Connect GND to common power/data ground
  • Connect the SCL pin to the I2C clock SCL pin on your Arduino compatible
  • Connect the SDA pin to the I2C data SDA pin on your Arduino compatible

 

SPI Wiring

Since this is a SPI-capable sensor, we can use hardware or 'software' SPI. To make wiring identical on all microcontrollers, we'll begin with 'software' SPI. The following pins should be used:

  • Connect Vin to the power supply, 3V or 5V is fine. Use the same voltage that the microcontroller logic is based off of
  • Connect GND to common power/data ground
  • Connect the SCK pin to Digital #13 but any pin can be used later
  • Connect the SDO pin to Digital #12 but any pin can be used later
  • Connect the SDI pin to Digital #11 but any pin can be used later
  • Connect the CS pin Digital #10 but any pin can be used later

Later on, once we get it working, we can adjust the library to use hardware SPI if you desire, or change the pins to others.

Install Adafruit_BME680 library

To begin reading sensor data, you will need to install the Adafruit_BME680 library (code on our github repository). It is available from the Arduino library manager so we recommend using that.

From the IDE open up the library manager...

And type in adafruit bme680 to locate the library. Click Install

Load Demo

Open up File->Examples->Adafruit_BME680->bmp680test and upload to your microcontroller wired up to the sensor

Depending on whether you are using I2C or SPI, change the pin names and comment or uncomment the following lines.

#define BME_SCK 13
#define BME_MISO 12
#define BME_MOSI 11
#define BME_CS 10

Adafruit_BME680 bme; // I2C
//Adafruit_BME680 bme(BME_CS); // hardware SPI
//Adafruit_BME680 bme(BME_CS, BME_MOSI, BME_MISO,  BME_SCK);

Once uploaded, open up the serial console at 9600 baud speed to see data being printed out

Temperature is calculated in degrees C, you can convert this to F by using the classic F = C * 9/5 + 32 equation.

Pressure is returned in the SI units of Pascals. 100 Pascals = 1 hPa = 1 millibar. Often times barometric pressure is reported in millibar or inches-mercury. For future reference 1 pascal =0.000295333727 inches of mercury, or 1 inch Hg = 3386.39 Pascal. So if you take the pascal value of say 100734 and divide by 3386.39 you'll get 29.72 inches-Hg.

Humidity is returned in Relative Humidity %

Gas is returned as a resistance value in ohms. This value takes up to 30 minutes to stabilize! Once it stabilizes, you can use that as your baseline reading. Higher concentrations of VOC will make the resistance lower.

You can also calculate Altitude. However, you can only really do a good accurate job of calculating altitude if you know the hPa pressure at sea level for your location and day! The sensor is quite precise but if you do not have the data updated for the current day then it can be difficult to get more accurate than 10 meters.

Last updated on 2017-11-08 at 03.15.25 PM Published on 2017-11-08 at 04.38.32 PM