Publish an Event to Wia Using 4 Lines of Code

Components

You will need the following components:

• Raspberry Pi 3 Model B+

• microSD card

• SD card adapter

• Micro USB to USB cable

• Ethernet cable (if connecting via ethernet)

• Computer with an SD slot (or an appropriate SD card adapter)

Installing the operating system

• Download Raspbian and extract the.img file.

• On Windows, right-click on the Zip file in your downloads folder and click Extract All.

• Insert the microSD into your computer's SD card slot via the SD card adapter.

• Next, you'll need to flash the Raspbian image to the microSD. There are various applications you can use to do this, such as Etcher for Linux, macOS or Windows.

• Open the SD card from your file explorer - the drive will be labelled boot.

• SSH access is disabled by default. To enable it, create an empty file in the boot drive called ssh.

• On Windows, inside the boot directory, right-click in the white space, scroll to New and select Text Document. Enter ssh as the name.

Connecting to the network

Option 1 - Via ethernet

• Connect the Raspberry Pi to your router via ethernet cable, and proceed to the next section.

Option 2 - Via WiFi

On Mac/Linux

• Create a new file in the boot drive called wpa_supplicant.conf.

• Follow code step below.

On Windows

• Download and install Notepad++ from here.

• Once installed, inside Notepad++ go to File > New to create a new file.

• In the top bar, select Edit > EOL Conversion. Make sure Unix (LF) is selected. It should appear disabled if it is.

• Select File > Save as, navigate to your boot drive and call the file wpa_supplicant.conf.

All OSs

• Paste in the following code:

• Text

country=IEctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdevupdate_config=1network={  scan_ssid=1  ssid="Your-SSID"  psk="Your-PSK"  key_mgmt=WPA-PSK}

Replace Your-SSID with your WiFi network, and Your-PSK with your WiFi password. This file will tell the Raspberry Pi to connect to the specified network when it boots up.

Make sure your computer is connected to the same network as your Raspberry Pi.

Booting up the board

• Eject the microSD card and insert it into the Raspberry Pi's microSD slot.

• Connect the PWR IN micro USB on your Raspberry Pi to a 5v power source (e.g. your computer's USB port).

• Wait for the board to boot up - the green LED should stop flashing when it's finished booting up.

Get your Raspberry Pi's IP Address

Option 1 - Login to your router

• If you have access to your router, you can login to it's admin panel via a browser. It's usually something like 192.168.0.1, 192.168.1.1 or 192.168.1.254.

• Look at the list of devices and find the IP address of your Pi. It should look something like 192.168.1.8.

Please note

When entering a password in terminal or command prompt, you won't see it being typed, for security reasons. Simply type the password and hit the enter key.

Option 2 - Scan using Nmap

The nmap command (Network Mapper) is a free and open-source tool for network discovery, available for Linux, macOS, and Windows.

• To install on Linux, install the nmap package. To do this, load your terminal and run the command apt-get install nmap. (If it does not run due to permissions, try sudo apt-get install nmap).

• To install on macOS or Windows, see the nmap.org download page here.

To use nmap to scan the devices on your network, you need to know the subnet you are connected to. First find your own IP address, in other words the one of the computer you're using to find your Pi's IP address:

• On Linux, type hostname -I into a terminal window

• On macOS, go to System Preferences then Network and select your active network connection to view the IP address

• On Windows, go to the Settings, then under Network and Internet, select your connection type i.e. Wi-Fi, Ethernet, click Properties (for some this is called Hardware Properties.

• In here, you will see IPv4 address. Now you have the IP address of your computer, you will scan the whole subnet for other devices. For example, if your IP address is 192.168.1.5, other devices will be at addresses like 192.168.1.2, 192.168.1.3, 192.168.1.4, etc.

In your terminal or Command Prompt, now use the nmap command with the -sn flag (ping scan) on the whole subnet range. This may take a few seconds: nmap -sn 192.168.1.0/24

Note: The 192.168.1 part in the command above should be replaced by the first 3 parts of the IP address you attained previously.

Ping scan just pings all the IP addresses to see if they respond. For each device that responds to the ping, the output shows the hostname and IP address like so:

Starting Nmap 6.40 ( http://nmap.org ) at 2018-04-02 12:51 GMTNmap scan report for Conalls-MBP (192.168.1.4)Host is up (0.0017s latency).Nmap scan report for iPhone (192.168.1.45)Host is up (0.0021s latency).Nmap scan report for raspberrypi (192.168.1.8)Host is up (0.0038s latency).Nmap done: 256 IP addresses (3 hosts up) scanned in 2.21 secondsHere you can see a device with hostname raspberrypi has IP address 192.168.1.8.

Option 3 - Use the hostname

By default, the hostname for the Raspberry Pi is raspberrypi. If you cannot get your IP address, you can try using raspberrypi.local instead.

Connecting to Raspberry Pi via SSH

On Mac and Linux

• Open a terminal window, and run ssh pi@ip-address.

• Replace ip-address with the one you attained in the previous step.

• You will be prompted to enter a password - the default password is raspberry.

On Windows

• Download Putty from here to allow you to communicate with your board via SSH.

• Under Host Name (or IP address) enter the IP address for your Raspberry Pi.

• Click the Open button to create the connection.

Publishing an event to Wia

• Once you're connected to the Raspberry Pi via SSH, run sudo apt-get install python-pip to install pip, a package manager.

• Run sudo pip install wia to install the Wia SDK.

• Create a new directory for your project by running mkdir my-project.

• Navigate into this new directory by running cd my-project. For this tutorial, we'll use python, but you can also use our Node.js SDK.

• Create a new python file by running touch test.py.

You can name the file anything you want, but make sure you don’t name it ‘wia.py’ as this will cause an ImportError.

• Edit the file with nano test.py.

• Paste in the following code snippet listed in the code below to get started

Replace your-access-token with your device's secret key (you can find this in your Wia dashboard, it begins with d_sk), and save the file by following the on screen instructions at the bottom.

• Run your newly created script by running python test.py.

• Navigate to the Wia Dashboard and you'll see that your device is connected.

• Navigate to the 'events' tab, and you'll see an event has been published.