Today I’m going to show you how to make sort of a mini weather station with a Raspberry Pi. This is an ongoing project of mine that I’ve been tinkering with so I’ll share my learnings with you. It started with a project I wrote about last month, and is an improvement on it.

A core part of the “Internet of Things” movement is the idea of devices that gather data and send it to the Internet. That data is then acted on or observed for later. It’s a simple concept and has been going on for a while but lately it’s been getting cheaper and easier to do. This project is a great example of that.

While this seems like a long tutorial, it only takes about 30 minutes to complete. Let’s get started.

Once you complete this your Raspberry Pi will measure:

• Temperature
• Humidity
• Atmospheric Pressure
• Lux

You can send your results to:

• Google Spreadsheet on your Google Drive
• ASP.Net Web API on your website

What you’ll need

For this project you will need:

• AM2302 Temperature / Humidity Sensor
• BMP180 Temperature / Barometric Pressure Sensor
• DS18B20 Waterproof Temperature Sensor
• TSL2561 Digital Lumosity Sensor

Optional:

• Breadboard and jumpers (Get a kit here)

None of this stuff would be anywhere near as easy if it weren’t for companies like 

Wiring

The wiring for this project is shown below:

While this may look confusing at first, it’s a pretty standard setup for each sensor. Here’s some additional information on how to wire up each one if the diagram isn’t helpful.

Installing the software

This tutorial has been tested with a fresh install of Raspian. The instructions should be fairly accurate for other Linux distributions as well.

SSH into the pi (or open a command window) and get’s start out in your home directory and make a folder for your sources.

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cd ~
mkdir sources
cd sources

Now we can start installing sensors.

Setup the AM2302

The AM2302 is a temperature humidity sensor. It is a DHT22 sensor that’s wired with a pullup resistor and casing. I found it easier to use this one than just the DHT22 kit.

For this sensor we’ll be using the Adafruit Python DHT library:

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git clone https://github.com/adafruit/Adafruit_Python_DHT.git
cd Adafruit_Python_DHT
sudo apt-get update
sudo apt-get install build-essential python-dev python-openssl
sudo python setup.py install

This will install the software necessary to interact with the AM2302

Test the AM2302

There is a test script you can use to verify the sensor is working. Run AdafruitDHT.py and “2302” is the sensor, and “22” is the pin you’re using. Change it if you hooked it to a different pin.

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cd examples
sudo ./AdafruitDHT.py 2302 22

You should see something that looks like this:

DSB18B20

The DSB18B20 is a digital one wire (Dallas one wire protocol) thermometer. If you get it “with extras” it comes with a cord and waterproof casing which is what I went with.

You will need to add one wire Support. Open up your boot config:

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sudo nano /boot/config.txt

Add the following text to that file: dtoverlay=w1-gpio

Save the file and reboot:

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sudo reboot

Testing the DSB18B20

To test it you’ll need to load the following modules into your kernel:

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sudo modprobe w1-gpio
sudo modprobe w1-therm

Note: you can do the following to add them to your kernel on boot:

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sudo nano /etc/modules

add the following lines:

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w1-gpio
w1-therm

Save the file and the next time you start they will be loaded automatically.

To check your device:

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cd /sys/bus/w1/devices
ls -la 

You will see a folder starting with 28- this is your device based on the serial number.

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cd 28-xxxx (change this to match what serial number pops up)
cat w1_slave

You should see something like the following:

If it says “YES” it’s working. If not, you may need to check your wiring.

Configuring I2C

Next you will need to configure I2C for your system:

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sudo apt-get install python-smbus
sudo apt-get install i2c-tools

You may get “already installed” messages from this, depending on how your system is setup.

Add the modules to your kernel on startup. Open up /etc/modules

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sudo nano /etc/modules

Add the following to it:

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i2c-bcm2708 
i2c-dev

Now you will need to modify your boot config:

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sudo nano /boot/config.txt

Add the following:

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dtparam=i2c1=on
dtparam=i2c_arm=on

Reboot your Pi:

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sudo reboot

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