Posts Tagged Wireless
Travel-Size Wireless Router for Your Raspberry Pi
Posted by Gary A. Stafford in Bash Scripting, Raspberry Pi, Software Development on July 15, 2013
Introduction
Recently, I purchased a USB-powered wireless router for to use with my Raspberry Pi when travelling. In an earlier post, Raspberry Pi-Powered Dashboard Video Camera Using Motion and FFmpeg, I discussed the use of the Raspberry Pi, combined with a webcam, Motion, and FFmpeg, to create a low-cost dashboard video camera. Like many, I find one the big challenges with the Raspberry Pi, is how to connect and interact with it. Being in my car, and usually out of range of my home’s wireless network, except maybe in the garage, this becomes even more of an issue. That’s where adding an inexpensive travel-size router to my vehicle comes in handy.
I chose the TP-LINK TL-WR702N Wireless N150 Travel Router, sold by Amazon. The TP-LINK router, described as ‘nano size’, measures only 2.2 inches square by 0.7 inches wide. It has several modes of operation, including as a router, access point, client, bridge, or repeater. It operates at wireless speeds up to 150Mpbs and is compatible with IEEE 802.11b/g/n networks. It supports several common network security protocols, including WEP, WPA/WPA2, WPA-PSK/WPA2-PSK encryption. For $22 USD, what more could you ask for!
My goal with the router was to do the following:
- Have the Raspberry Pi auto-connect to the new TP-LINK router’s wireless network when in range, just like my home network.
- Since I might still be in range of my home network, have the Raspberry Pi try to connect to the TP-LINK first, before falling back to my home network.
- Ensure the network was relatively secure, since I would be exposed to many more potential threats when traveling.
My vehicle has two power outlets. I plug my Raspberry Pi into one outlet and the router into the other. You could daisy chain the router off the Pi. However, my Pi’s ports are in use my the USB wireless adapter and the USB webcam. Using the TP-LINK router, I can easily connect to the Raspberry Pi with my mobile phone or tablet, using an SSH client.
Using Fing to Locate the Pi on the TP-LINK Wireless Network
When I arrive at my destination, I log into the Pi and do a proper shutdown. This activates my shutdown script (see my last post), which moves the newly created Motion/FFmpeg time-lapse dash-cam videos to a secure folder on my Pi, before powering down.
Using SSH Terminal for iOS to Shutdown the Pi
Of course there are many other uses for the router. For example, I can remove the Pi and router from my car and plug it back in at the hotel while traveling, or power the router from my laptop while at work or the coffee shop. I now have my own private wireless network wherever I am to use the Raspberry Pi, or work with other users. Remember the TP-LINK can act as a router, access point, client, bridge, or a repeater.
The Raspberry Pi and Router both fit in a Small Container for Travel
Network Security
Before configuring your Raspberry Pi, the first thing you should do is change all the default security related settings for the router. Start with the default SSID and the PSK password. Both these default values are printed right on the router. That’s motivation enough to change!
Additionally, change the default IP address of the router and the username and password for the browser-based Administration Console.
Lastly, pick the most secure protocol possible. I chose ‘WPA-PSK/WPA2-PSK’. All these changes are done through the TP-LINK’s browser-based Administration Console.
Configuring Multiple Wireless Networks
In an earlier post, Installing a Miniature WiFi Module on the Raspberry Pi (w/ Roaming Enabled), I detailed the installation and configuration of a Miniature WiFi Module, from Adafruit Industries, on a Pi running Soft-float Debian “wheezy”. I normally connect my Pi to my home wireless network. I wanted to continue to do this in the house, but connect the new router when traveling.
Based on the earlier post, I was already using Jouni Malinen’s wpa_supplicant, the WPA Supplicant for Linux, BSD, Mac OS X, and Windows with support for WPA and WPA2. This made network configuration relatively simple. If you use wpa_supplicant, your ‘/etc/network/interfaces’ file should look like the following. If you’re not familiar with configuring the interfaces file for wpa_supplicant, this post on NoWiresSecurity.com is a good starting point.
Note that in this example, I am using DHCP for all wireless network connections. If you chose to use static IP addresses for any of the networks, you will have to change the interfaces file accordingly. Once you add multiple networks, configuring static IP addresses for each network, becomes more complex. That is my next project…
First, I generated a new pre-shared key (PSK) for the router’s SSID configuration using the following command. Substitute your own SSID (‘your_ssid’) and passphrase (‘your_passphrase’).
wpa_passphrase your_ssid your_passphrase
Based your SSID and passphrase, this command will generate a pre-shared key (PSK), similar to the following. Save or copy the PSK to the clipboard. We will need the PSK in the next step.
Then, I modified my wpa_supplicant configuration file with the following command:
sudo nano /etc/wpa_supplicant/wpa_supplicant.conf
I added the second network configuration, similar to the existing configuration for my home wireless network, using the newly generated PSK. Below is an example of what mine looks like (of course, not the actual PSKs).
Depending on your Raspberry Pi and router configurations, your wpa_supplicant configuration will look slightly different. You may wish to add more settings. Don’t consider my example the absolute right way for your networks.
Wireless Network Priority
Note the priority of the TP-LINK router is set to 2, while my home NETGEAR router is set to 1. This ensures wpa_supplicant will attempt to connect to the TP-LINK network first, before attempting the home network. The higher number gets priority. The best resource I’ve found, which explains all the configuration options is detail, is here. In this example wpa_supplicant configuration file, priority is explained this way, ‘by default, all networks will get same priority group (0). If some of the networks are more desirable, this field can be used to change the order in which wpa_supplicant goes through the networks when selecting a BSS. The priority groups will be iterated in decreasing priority (i.e., the larger the priority value, the sooner the network is matched against the scan results). Within each priority group, networks will be selected based on security policy, signal strength, etc.’
Conclusion
If you want an easy, inexpensive, secure way to connect to your Raspberry Pi, in the vehicle or other location, a travel-size wireless router is a great solution. Best of all, configuring it for your Raspberry Pi is simple if you use wpa_supplicant.
Remote Motion-Activated Web-Based Surveillance with Raspberry Pi
Posted by Gary A. Stafford in Bash Scripting, Raspberry Pi on January 1, 2013
Introduction
Want to keep an eye on your home or business while you’re away? Maybe observe wildlife close-up without disturbing them? Or, keep an eye on your kids playing in the backyard? Low-end wireless IP cameras start at $50-$75 USD. Higher-end units can run into the hundreds of dollars. Add motion detection and the price raises even further. How about a lower-cost solution? Using a Raspberry Pi with an inexpensive webcam, a wireless WiFi Module, and an optional battery pack, you can have a remote, motion-activated camera solution, at a fraction of the cost. Best of all, you won’t need to write a single line of code or hack any electronics to get started.
Motion
There are many posts on the Internet, demonstrating how to build a Raspberry Pi-powered motion-activated camera system. One of the more frequently used off-the-shelf applications for these projects is Motion. According to their website, ‘Motion is a program that monitors the video signal from one or more cameras and is able to detect if a significant part of the picture has changed; in other words, it can detect motion‘. Motion uses a technique known as visual motion detection (VMD) to compare a series of sequential camera frames for differences at a pixel level. A change between a series of sequential frames is an indication of movement.
Motion has the ability to stream images from a webcam and server them from it’s built-in web server, with little or no configuration. In addition, Motion is easily configured to work with streaming video applications like the very popular FFmpeg, and save images to databases like mySQL or PostgreSQL. Motion can also execute external scripts such as python or shell. In this post, we are going to use Motion’s most basic features, motion detection and web-streaming.
Installing Motion
Firmware Update
Before installing Motion, I recommend ensuring your Raspberry Pi is up-to-date with the latest software and firmware. Updating firmware is not necessary. However, I was recently helping someone with camera issue on their Raspberry Pi. Finding a few suggestions online for similar problems, we updated the firmware on the Raspberry Pi. It fixed the problem. Installing firmware can sound a bit intimidating. However, Liam McLoughlin (hexxeh) has made the process easy with rpi-update. I have used it successfully on multiple Raspberry Pi’s. Three commands is all it takes to update your Raspberry Pi to the latest firmware.
Software Update
You should also update your Raspberry Pi’s existing software. To update your Raspberry Pi’s software, execute the following apt-get commands:
sudo apt-get update && sudo apt-get upgrade
If you don’t do this on a regular basis, as recommended, these could take up to several minutes. Watch for errors. If there are any errors, try to run the command again. Sometimes the Raspberry Pi cannot connect to all code repositories for updates.
Installing Motion
Once the updates are complete, install Motion by issuing the following command:
sudo apt-get install motion
Enabling Motion
As the installation completes, you should see a warning in the command shell about Motion being disabled by default.
... Adding user `motion' to group `video' ... Adding user motion to group video Done. [warn] Not starting motion daemon, disabled via /etc/default/motion ... (warning). Setting up ffmpeg (6:0.8.4-1) ... pi@garyrasppi ~ $
To enable Motion (the motion daemon), we need to edit the /etc/default/motion file.
sudo nano /etc/default/motion
Change the ‘start_motion_daemon‘ parameter to ‘yes’.
Configuring Motion
Motion is easy to customize with loads of parameters you can tweak based on your needs. Motion has no GUI. All configuration is all done through Motion’s configuration file (/etc/motion/motion.conf). Before editing the configuration file, we need to change the permissions on it, so Motion can get access to it. While we are at it, we will also change permissions on the folder where Motion stores captured images.
sudo chmod -R 777 /etc/motion/motion.conf sudo chmod -R 777 /tmp/motion
After changing the permissions, to configure Motion, open the Motion’s configuration file in a text editor, as root (sudo). I like using Nano. The configuration file can be opened in Nano with the following command:
sudo nano /etc/motion/motion.conf
Motion’s configuration file is lengthy. However, it is broken down into logical sections, making finding the setting you are looking for, easy. First, we need to change the ‘Live Webcam Server’ section of configuration. Below are the default settings:
############################################################ # Live Webcam Server ############################################################ # The mini-http server listens to this port for requests (default: 0 = disabled) webcam_port 8081 # Quality of the jpeg (in percent) images produced (default: 50) webcam_quality 50 # Output frames at 1 fps when no motion is detected and increase to the # rate given by webcam_maxrate when motion is detected (default: off) webcam_motion off # Maximum framerate for webcam streams (default: 1) webcam_maxrate 1 # Restrict webcam connections to localhost only (default: on) webcam_localhost on # Limits the number of images per connection (default: 0 = unlimited) # Number can be defined by multiplying actual webcam rate by desired number of seconds # Actual webcam rate is the smallest of the numbers framerate and webcam_maxrate webcam_limit 0
The first thing you will want to change is Motion’s default setting that restricts image streaming to ‘localhost‘, only ( ‘webcam_localhost on‘). This means you can only view images in a web browser on the Raspberry Pi, not remotely over your network. Change that line of code to read ‘webcam_localhost off‘.
The next setting I recommend changing for security purposes is the default port Motion’s web server uses to stream images, 8081. Security through obscurity is better than no security at all. Change port 8081 to a different arbitrary port, for example, 6789 (‘webcam_port 6789‘). Just make sure you don’t pick a port already in use by another service or application. Having made this change, if your Raspberry Pi’s local IP address is 192.168.1.9, images from the webcam should be accessible at 192.168.1.9:6789.
The other two settings in this section you can play with are the webcam quality and maximum frame-rate. You will have to adjust this based on your network speed and the processing power of your Raspberry Pi. The default settings are a good place to start. I changed my quality from the default of 50 to 80 (‘webcam_quality 80‘), and changed my max frame-rate to 2 (‘webcam_maxrate 2‘).
Speaking of quality, the other two settings you may want to change are the width and height of the image being captured by Motion. The ‘Capture device options’ section is where we change these settings. As the configuration’s comments suggest, these settings are dependent on your camera. Check the camera’s available image sizes; you will need to use one of those size combinations. I have mine set to an average size of 352 x 288. This is a good size for those of us with a slower network, or when streaming video over the Internet to mobile web browser. Conversely, a larger image is better for viewing over your local network.
Image size, like compression quality, and frame-rate are dependent on processing power of your Raspberry Pi and it’s OS (Raspbian, Debian, Arch, etc.). You may need to play with these settings to get the desired results. I couldn’t stream images larger than 352 x 288 over the Internet, with my Raspberry Pi, even though my webcam could capture up to 640 x 480 pixels.
# Image width (pixels). Valid range: Camera dependent, default: 352 width 352 # Image height (pixels). Valid range: Camera dependent, default: 288 height 288
It’s important to remember, each time you make changes to Motion’s configuration file, you must restart Motion, using the following command.
sudo /etc/init.d/motion restart
Viewing Your Webcam Remotely
To view your webcam’s output from another device on your local network, point your web browser to the IP address of your Raspberry Pi, and add the port you assigned in Motion’s configuration file. Motion may take up to 15-20 seconds to start responding in the browser. If it takes longer, you probably have your image size, frame-rate, and compression settings to high for your Raspberry Pi.
Over the Internet
Enabling your webcam’s output over the Internet is relatively easy with the average home router and Internet service provider. Suppose the IP address of my Raspberry Pi, on my local network, is 192.168.1.9. Suppose I assigned port 6789 to Motion’s web server. Lastly, suppose my router’s external Internet IP address is 113.45.67.88. With this information, I can create a port-forwarding rule in my router, allowing all external HTTP traffic over TCP to 113.45.67.88:3456, to be automatically forwarded internally to 192.168.1.9:6789. The external port, 3456, is totally arbitrary, just make sure you don’t pick a port already in use.
IMPORTANT SECURITY NOTE: There are no passwords or other network protection used with this method. Make sure to keep the external IP address and port combination private, and always stop Motion, or better yet your Raspberry Pi, when not in use. Otherwise, someone could potentially be watching you!
Down at the local coffee shop, I decide to check if the mailman has delivered my new Raspberry Pi to the front porch. Having set-up port-forwarding, I enter 113.45.67.88:3456 in my smartphone’s web browser. My Internet provider routes the HTTP request to my Internet router. My router receives the request and forwards it over my local network to 192.168.1.9:6789, where Motion’s built-in web server on my Raspberry Pi is running. Motion’s web server responds by streaming still images back to my phone at the coffee shop when it detects motion. Still no sign of the mailman or my Raspberry Pi…
Static IP Addresses
I recommend using a static IP address for your Raspberry Pi, versus DHCP, if possible. Else, you will have to change your router’s port-forwarding rules each time your Raspberry Pi’s DHCP lease is renewed and its local IP address changes. There are some ways to prevent addressed from changing frequently with DHCP, if your router supports it. Look for configurable lease times or reservations options in your router’s configuration; these may be able to be extended.
Locating Your External Internet IP Address
What is your router’s external Internet IP address? To find mine, I looked in Netgear’s Router Status window. You can also use a ‘tracert’ from the command line, if you know what to look for in the output.
Since I do not pay my Internet-provider for a static external Internet IP address, the address my provider assigns to my router is dynamic. It can and will change, sometimes almost never, or sometimes daily. The frequency of change depends on your provider. To view your webcam’s images, you will need to know your router’s current external Internet IP address.
Motion Example
Here are some example from a Microsoft LifeCam VX-500 and Logitech Webcam C210 webcams. The highest quality I could consistently stream over the Internet, from my Raspberry Pi 512Mb Model B, with both Soft-float Debian “wheezy” and Raspbian “wheezy”, was 352 x 288 at 80% compression and 2 fsp max. Locally on my LAN, I could reach a frame size of 640 x 480 pixels.
In the first example, I’ve placed the Raspberry Pi in a plastic container to protect it, and mounted the webcam in a flower box. Viewing the feed over my local network, we are able to watch the hummingbirds without scaring them.
In the next two images, I’ve turned on Motion’s ‘locate box’ option, which tracks the exact area within the image that is moving. As the person come into view of the camera mounted near the front door, Motion detects and outlines the area of the images where it detects movement.
In the next video, you see the view from a Google Nexus 7 tablet. My wife and I use the Raspberry Pi surveillance system to watch our backyard when our kids are outside (the camera is no substitute for adult supervision when the kids are in the pool).
This last image is from my iPhone, while shopping at the local grocery store. My wife was impressed with my port-forwarding knowledge. OK, not really, but she did enjoy showing off the Christmas tree to friends, remotely, even if it wasn’t in motion.
Useful Links
Here are a few links to other useful articles on the use of Motion with the Raspberry Pi:
Raspberry Pi-Powered Dashboard Video Camera Using Motion and FFmpeg
Setup a webcam security system with Ubuntu Linux and Motion
Guest blog #7: Bird table webcam by Francis Agius
motion(1) – Linux man page (good source for understand Motion config)
Linux UVC Supported Devices (a good starting point for buying a webcam)
Installing a Miniature WiFi Module on the Raspberry Pi (w/ Roaming Enabled)
Posted by Gary A. Stafford in Raspberry Pi on December 30, 2012
Background
In a earlier post, Installing a Miniature WiFi Module on the Raspberry Pi (w/o Roaming Enabled), I detailed the installation and configuration of a Miniature WiFi Module, from Adafruit Industries, on a RaspPi running Soft-float Debian “wheezy”. As I mentioned in that post, there was more than one method of configuring the WiFi Module (WNIC) on a WLAN, based on the research I did. I chose the simple method of hard-coding a single WLAN configuration into the ‘/etc/interfaces’ file.
Recently, while installing the same type WiFi Module (WNIC) on a RaspPi running Raspbian “wheezy”, I chose the alternate method. This involves adding the WLAN configuration to the wpa_supplicant configuration file (‘/etc/wpa_supplicant/wpa_supplicant.conf’). You can add multiple WLAN configurations to the wpa_supplicant configuration file. This allowing the RaspPi to roam from networks to network, automatically connecting to those that are configured.
If you’re not comfortable configuring networks from the command shell, you can also use the wpa_gui application (aka wpa_suppicant user interface) from the RaspPi’s desktop. It allows you to edit the same configuration from a gui, just as we will do manually in the command shell.
Installing the WiFi Module Driver
Copy the ‘Linux and Android’ Realtek driver folder from the CD, supplied by the manufacturer, to the ‘tmp’ folder on the RaspPi using WinSCP. Then, run the following commands:
cd / cd /tmp/Linux\ and\ Android chmod +x install.sh sudo ./install.sh
Remember to select #1 when asked to choose a card type:
... Please select card type(1/2): 1) RTL8192cu 2) RTL8192du #? 1
You can insert the WiFi Module at this point in the process.
Installing Wireless LAN Security Protocol Software
As detailed in the earlier post, we need to install software that allows us to configure and connect to our WPA/WPA2-secured wireless network. The particular software is referred to as ‘wpa_supplicant’. To install ‘wpa_supplicant’ and the ‘wpagui’, enter the following commands. Note this will check for any upgrades to the RaspPi’s existing software, first. This is a commonly-recommended step. The upgrade command might take a few minutes if you haven’t run this on your RaspPi in a while.
sudo apt-get update && sudo apt-get upgrade sudo apt-get install wpasupplicant wpagui
Configuring the New WiFi Adapter
Examine the contents of the ‘/etc/networks/interfaces’ file, by entering the following command:
sudo cat /etc/network/interfaces
Unlike in the first post, we will make no changes to this file. The ‘/etc/networks/interfaces’ file should have the default settings for both the current NIC (eth0) as well as for the WNIC (wlan0), as shown below. Note the reference to the ‘/etc/wpa_supplicant/wpa_supplicant.conf’ file. Why are the file’s contents different than in the first post? Because we installed ‘wpagui’.
WPA Supplicant Configuration
Enter the following command, substituting your own SSID (‘your_ssid’) and passphrase (‘your_passphrase’).
wpa_passphrase your_ssid your_passphrase
Based your SSID and passphrase, this command will generate a pre-shared key (PSK), similar to the following. Save or copy the PSK to the clipboard; we will need it in the next step.
Next, open the ‘/etc/wpa_supplicant/wpa_supplicant.conf’ file using Nano, by entering the following command:
sudo nano /etc/wpa_supplicant/wpa_supplicant.conf
Add the following code at the end of the file. Remember to substitute your_ssid and your_psk_or_passphrase. Note the following settings are specific to my WPA2-secured network. If you are using WPA, refer to this post for the correct WPA settings.
network={
ssid="your_ssid"
proto=RSN
key_mgmt=WPA-PSK
pairwise=CCMP
group=CCMP
psk="your_psk_or_passphrase"
}
Your final file should look similar to this:
Save the file and exit Nano. Lastly, execute the following series of commands to assign an IP address to the new WNIC.
sudo wpa_supplicant -d -c /etc/wpa_supplicant/wpa_supplicant.conf -i wlan0 -D wext sudo ifconfig wlan0 up sudo dhclient wlan0 sudo wpa_supplicant -B -c /etc/wpa_supplicant/wpa_supplicant.conf -i wlan0 -D wext ip addr show wlan0
You should see an IP Address for ‘wlan0’ displayed. That it, shutdown the RaspPi, remove the Ethernet cable, and restart the RaspPi. Use a program like ‘Advanced IP Scanner’ for Windows, or ‘Fing’ for iOS, to discover the wireless IP address of the RaspPi. The RaspPi will show up with the WiFi chipset manufacturer’s name, ‘REALTEK SEMICONDUCTOR’ or ‘REALTEK SEMICONDUCTOR CORP.’. Use this address to re-connect to the RaspPi.
Need to add another network’s configuration? Simply enter the information in the ‘/etc/wpa_supplicant/wpa_supplicant.conf’ and restart. Here are a few good articles I found on configuring a WiFi Module on the RaspPi with roaming:
http://hostap.epitest.fi/wpa_supplicant/
http://www.cyberciti.biz/faq/linux-ndiswrapper-wpa_supplicant-howto/
http://linux.die.net/man/5/wpa_supplicant.conf
http://ubuntuforums.org/showthread.php?t=1259003
http://ubuntuforums.org/showthread.php?t=318539
http://unix.stackexchange.com/questions/7817/how-to-find-out-which-wi-fi-driver-is-installed
Installing a Miniature WiFi Module on the Raspberry Pi (w/o Roaming Enabled)
Posted by Gary A. Stafford in Raspberry Pi on December 25, 2012
One of the best purchases I’ve made recently was a Miniature WiFi Module for my Raspberry Pi, from Adafruit Industries. No more having my RaspPi tethered to an Ethernet port on my wireless router. I can have my RaspPi with me, wherever I’m working. At the same time, I have Internet access on both my laptop and the RaspPi. All this for less than $12!
Background
The Miniature WiFi Module is technically a wireless network interface controller (WNIC). It connects the RaspPi to a wireless local area network (WLAN). Wherever you see the word ‘Interface’ in this post, it is referring to either the new Miniature WiFi Module, or the built-in network interface controller (NIC), which connects the RaspPi to a local area network (LAN) via Ethernet.
In researching how to properly install and configure the WiFi Module, I read a number of articles and posts on the Internet. The simplest approach I found was presented in this article by Macro M.C. on MacroMC.com. Much of the following is based on his article. Marco directly edits the ‘interfaces’ file, instead of also editing the ‘wpa_supplicant.conf’ file, as is demonstrated in other posts. I will only be connecting my RaspPi to a single WLAN in this post. If you will be switching between multiple WLANs with your RaspPi, you might want to investigate the alternate method of editing the ‘wpa_supplicant.conf’ file, or using the wpa supplicant user interface, instead.
I will be installing and configuring my RaspPi using a Windows laptop. However, if you are using a Mac or Linux-based computer, you shouldn’t need change these directions. Also, I am using the WPA2-Personal security protocol on my home’s wireless network. These directions should work for both commonly used WPA and WPA2 wireless network security protocols; I will explain further in step 2. Lastly, since I largely develop Java SE Embedded applications for the Raspberry Pi, I have installed Soft-float Debian “wheezy” on my RaspPi. However, these directions should also work for the more commonly installed Raspbian “wheezy”, as well.
Getting Started
The configuration and installation of the Miniature WiFi Module takes less 15 minutes. I’ve broken the process down into three steps:
- Installing the WiFi Module driver
- Installing wireless LAN security protocol software
- Configuring the new WiFi Module
Before we start, make sure you have the following items available:
- Your wireless network’s name (aka SSID)
- Your network security key (aka passphrase)
- SSH enabled on your RaspPi
- LAN access to your RaspPi
- Internet access from your RaspPi
- PuTTY to your RaspPi
- WinSCP to copy files to your RaspPi
- Advanced IP Scanner, Fing, or similar network scanning software (optional)
Installing the WiFi Module Driver
Don’t insert the WiFi Module into the RaspPi, yet. Instead, connect the RaspPi to your LAN using an Ethernet cable. Make sure the RaspPi has Internet access. Insert the small CD that comes with the WiFi Module into your laptop’s CD/DVD player. Connect to the RaspPi from your laptop using WinSCP. Copy the ‘Linux and Android’ folder from the CD to the ‘tmp’ folder on the RaspPi, as shown below.
Before we install the driver, let’s examine the current network interface configuration on the RaspPi. Log into your RaspPi using PuTTY. Using the ifconfig command, you should only see the built-in NIC (eth0), as shown in the example below.
Realtek is the WiFi Module’s chipset manufacturer. To install the Realtek WiFi Module driver on the RaspPi, enter the following series of commands.
cd / cd /tmp/Linux\ and\ Android chmod +x install.sh sudo ./install.sh
During the install you’ll be prompted to select between two card types, enter 1;
... Please select card type(1/2): 1) RTL8192cu 2) RTL8192du #? 1
Installing Wireless LAN Security Protocol Software
After installing the driver, we need to install software that allows us to configure and connect to our WPA-secured wireless network. The particular software is referred to as ‘wpa_supplicant’. According to Jouni Malinen, wpa_supplicant is a WPA Supplicant for Linux, BSD, Mac OS X, and Windows with support for WPA and WPA2 (IEEE 802.11i / RSN). It is suitable for both desktop/laptop computers and embedded systems. Supplicant is the IEEE 802.1X/WPA component that is used in the client stations. It implements key negotiation with a WPA Authenticator and it controls the roaming and IEEE 802.11 authentication/association of the wlan driver.
To install wpa_supplicant, enter the following commands. Note this will check for any upgrades to the RaspPi’s existing software, first. This is a commonly-recommended step. The upgrade command might take a few minutes if you haven’t run this on your RaspPi in a while.
sudo apt-get update && sudo apt-get upgrade sudo apt-get install wpasupplicant
Next, enter the following command, substituting your own SSID (‘your_ssid’) and passphrase (‘your_passphrase’).
wpa_passphrase your_ssid your_passphrase
Based your SSID and passphrase, this command will generate a pre-shared key (PSK), similar to the following. Save or copy the PSK to the clipboard; we will need it in the next step.
Configuring the New WiFi Adapter
The last step is to configure the new WiFi Module (WNIC) for your WLAN. Open the ‘/etc/networks/interfaces’ file using Nano, by entering the following command.
sudo nano /etc/network/interfaces
This file will only have the default settings for the current NIC (eth0), as shown below.
To add the new WNIC (wlan0), enter the following lines of code to the end of the ‘interfaces’ file. Substitute you SSID (‘your_ssid’) in quotes and the PSK you generated in the previous step. Do not use the SSID and PSK below, it will not work for your network, it is only an example.
auto wlan0 allow-hotplug wlan0 iface wlan0 inet dhcp wpa-ssid "your_ssid" wpa-psk b2abb0fcd2f4527e11817de0823a57bb19ba4622f4595062c94ec4dd1370b5fe
Save the file and exit Nano. Shutdown the RaspPi and remove the Ethernet cable. Insert the Miniature WiFi Module and restart the RaspPi. You should not run the RaspPi with both the LAN and WLAN Interfaces connected.
Finding the Raspberry Pi’s Wireless Address
Since you used Dynamic Host Configuration Protocol (DHCP) in the interface’s configuration, the Module has been assigned a new IP address. To find the RaspPi’s new wireless IP address, log directly into the RaspPi and use the ifconfig command. Alternately, we can use a program like ‘Advanced IP Scanner’ for Windows or ‘Fing’ for iOS, to discover the address of the RaspPi. The RaspPi will show up with the WiFi chipset manufacturer’s name, ‘REALTEK SEMICONDUCTOR’ or ‘REALTEK SEMICONDUCTOR CORP.’.
In the example below from Fing on an iPhone, there are two wireless RaspPi’s on my network, an inactive wireless RaspPi at 192.168.1.7, and my active wireless RaspPi at 192.168.1.9.
Here is another view of my network using Advanced IP Scanner on Windows. My active wireless RaspPi at 192.168.1.9.
If you are unable to find your RaspPi on the WLAN, re-connect to the RaspPi directly and check for errors. I had to do this on more than a few occasions while researching this post, mostly due to typos in my interface file. Try rebooting the RaspPi and watch the shutdown and boot-up screens for errors.; network errors will often show up here.
Use the RaspPi’s new wireless IP address you found to connect back into your RaspPi with PuTTY. To better understand how the new WiFi Module (WNIC) is configured, run the ifconfig command, again. This time you should see both the NIC (eth0) and WNIC (wlan0).
Congratulations, your RaspPi is wireless. Please feel free to ‘move about the cabin’. -gs
Gary Stafford
AWS Area Principal Solutions Architect | 10x AWS Certified Pro | DevOps | Data/ML | Serverless | Polyglot Developer | Former ThoughtWorks and Accenture
Programmatic Ponderings 