Raspberry Pi Weather Station

Raspberry Pi is a perfect tool to get Internet of Things (IoT) up and running - a Linux computer with access to I2C.

Hardware components

• Raspberry Pi 3 Model B x 1
  With micro-USB power supply, micro-SD card and Ethernet cable to router
• XinaBox BR01 x 1
  xChip Interface to Raspberry Pi
• XinaBox SW01 x 1
  xChip based on the BME280 Weather Sensor
• XinaBox XC10 x 1
  xBUS connector between xChips

Software apps and online services

• Raspberry Pi Raspbian Lite
• Etcher

This is an example of building a weather station using a few components, that clicks together with no need for wiring or soldering.

• Download Raspbian Lite and unzip
• Download Etcher and install
• Insert the Micro-SD card into your computer
• Run Etcher using Raspbien Lite as input and the Micro-SD card as output
• Create a empty file called 'ssh' on the root of the Micro-SD card. On a Mac that is easiest done by opening a terminal window and type:

cd /Volumes/boot
touch ssh

• Now eject the Micro-SD card from your computer.

Assemble the Raspberry Pi with the xChips as illustrated in the "video" at the top.

• Click the IR02 into the Raspberry Pi with the header connected to the pins closest to the Micro-SD card end of the Pi
• Click an XC10 connector into the IR02
• Click the SW01 into the connector. Make sure the sensor is facing up (the SW01 name is facing up, similar to the IR02 name), and make sure the xChips are aligned. Only 2 of the sides of the SW01 will fit into the IR02.
• Insert the Micro-SD card into the Raspberry Pi
• Connect an Ethernet cable from your router to the Pi
• Connect a Micro-USB power source to your Pi

• Connect to your Raspberry Pi using ssh. From a Windows computer, you have to install an ssh program such as PuTTY, but from a Mac you simply open a terminal window, and type:

ssh pi@raspberrypi.local

The default password is 'raspberry'.

Once you are logged in, type this:

sudo raspi-config

That opens a configurations program where you:

• Choose: 5 Interfacing Options
• Then choose: P5 I2C
• Then answer "Yes" to "Would you like the ARM I2C interface to be enabled?"

Then we need to install a bit of software:

sudo apt-get update
sudo apt-get install i2c-tools python-pip
sudo pip install RPi.bme280

Let's just check that we can see the Weather sensor, type:

i2cdetect -y 1

And see if you get this:

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 --
pi@raspberrypi:~ $

Copy the 5 line program below into a file. Let's call it test.py, just cut and paste the following into you terminal

echo '
import smbus2
import bme280
bus = smbus2.SMBus(1)
bme280.load_calibration_params(bus, 0x76)
print(bme280.sample(bus, 0x76))
' > test.py

Now run the code:

python test.py

...and you should see this:

pi@raspberrypi:~ $ python test.py
compensated_reading(id=7c98f6f7-a677-4766-92dd-8b5def7c038a, timestamp=2017-10-09 21:03:46.202243, temp=27.583 °C, pressure=1023.24 hPa, humidity=38.52 % rH)
pi@raspberrypi:~ $

Weather Station Demo Python
A small Python demo reading the weather information from the SW01. Code kept short for simplicity.

import smbus2
import bme280
bus = smbus2.SMBus(1)
bme280.load_calibration_params(bus, 0x76)
print(bme280.sample(bus, 0x76))