A pimatic plugin for modules based on the BME280 sensor. It uses the node-bme280 driver from CLCL/node-BME280.

Add a device via the web UI or by editing the config file.

    {
      "class": "BME280Sensor"
      "id": "bme280-test",
      "name": "BME280 test",
      "device": "i2c-1",
      "address": "0x76",
      "interval": 10000,
      "xLink": "",
    }

Check using dir /dev/i2c* to see the name of your device. USe i2cdetect to determine the address. If you can't find this command use sudo apt-get install -y i2c-tools.

pi@raspberrypi:~/$ i2cdetect -y 1
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:          -- -- -- -- -- -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- 76 --

Copied steps from here: https://learn.sparkfun.com/tutorials/raspberry-pi-spi-and-i2c-tutorial#i2c-on-pi

I2C is not turned on by default. We can use raspi-config to enable it.

1. Run sudo raspi-config.
2. Use the down arrow to select 9 Advanced Options
3. Arrow down to A7 I2C.
4. Select yes when it asks you to enable I2C
5. Also select yes when it tasks about automatically loading the kernel module.
6. Use the right arrow to select the <Finish> button.
7. Select yes when it asks to reboot.

The system will reboot. when it comes back up, log in and enter ls /dev/*i2c*. The Pi should respond with /dev/i2c-1 which represents the user-mode I2C interface.